Section 12: Big Bimmers (7-series, 8-series)

Chapter Editor: Steve Callaghan (Stephen.CALLAGHAN_at_ipb.qld.gov.au)

12.1: Overview
12.2: Body

       12.2.1 E23 center console
       12.2.2 E32 Power Seats
   12.3: Engine & Transmission
       12.3.1  '88 735i hard starts
       12.3.2 Temperature sensor and oil drip
       12.3.3   [735i] Transmission Faliures
   12.4: Suspension & Steering
       12.4.1 Steering Wheel Shimmy
       12.4.2 Power Steering booster
       12.4.3  E28 ZF steering box (same principal as E23/E32)
       12.4.4  Power Steering Pumps
       12.4.5  Re: 7er struts DIY
   12.5: Brakes
       12.5.1  Proper brake bleeding proceedure (745i)
       12.5.2  Brake Noise, 735i
       12.5.3  Brake Pressure Warning Message
   12.6: HVAC
       12.6.1 Fan Control
       12.6.2  1989 E32 Microfilter, Glovebox, HVAC Fan
       12.6.3  <850i> squeaks from HVAC
       12.6.4  Water control solenoid 7er heat
   12.7: Electrical
       12.7.1  Firmware Upgrades?
       12.7.2  Replacing OBC Light Bulb
       12.7.3  735il EML failure
       12.7.4 Tachometer not working
       12.7.5   Mirror Tilt
       12.7.6  Retrieving Motronic Codes From Your Car
       12.7.7  climate control lights
   12.8: Misc
       12.8.1 Official BMW Cruise Diagnosis (long and taken from E28, but the 
same)
       12.8.2  535 Fuel Delivery Problems? (same for 3.5l 7er)
       12.8.3 Checklist

12.9: Performance

From: "jlcl01::mrgate::a1::pappentl"_at_jlcl01.dnet.dupont.com Date: Sat, 22 Jun 96 19:57:14 EDT
Subject: E23 center consloe

Help! I need to remove the center console on my 1984 735i so I can repair a leak in one of the air vent vacuum lines. I can get the cover off the parking brake, but I am clueless as to the center console. There is a screw on the casette holder, and a 10mm nut that was hidden by the brake cover, but what else is holding this console on?

...Tom

pappentl_at_udel.ed

On Sat, 22 Jun 96, "jlcl01::mrgate::a1::pappentl"_at_jlcl01.dnet.dupont.com wrote:

>Help! I need to remove the center console on my 1984 735i so I

(snipped)...
>center console. There is a screw on the casette holder, and a >10mm nut that was hidden by the brake cover, but what else is >holding this console on?
You're almost there. Apart from the frontal 10mm nut, you'll have to remove another 2 screws - reach from the rear air-vents. Just pull off the air-vents control slider. Undo 2 screws that hold the air-vents shroud. Pull off the cig. lighter wire - make sure they don't *short* to bare metal. With the air-vents shroud removed, you'll see another 2 screws that hold the rear end of the whole lower center console over the hand-brake unit. For complete removal, you'll then have to disconnect/unplug all the power-window switches. That's about it. Cheers!

>...Tom

>pappentl_at_udel.edu

• -- chL00I via DeskTopPC West Malaysia. 84 E23 728i 71 Opel Manta SR

Philip Patrick asked about working on power seats.

Go for it Phillip. These things are easy to work on and really very simple. If you have to get under the seat, remove the pins at the front of the seat and just let if flop back.

I've hacked just about everything on mine, including removing and repairing the seat control switches (only for the truly demented).

Yell if you have questions and I'll help where I can.

Good Luck,

Doug

Today I took your advice and pulled the head rest motors to check the = cables. On the driver side seat, I put a 1/2 inch piece of coat hanger = down in the motor shaft. It worked great. On the passenger side I had = to pull the cable out and cut the sheath at the edge of the metal ring = that inserts in the motor. Then I had to pry the small piece of sheath = out of the ring. There are a couple of cutouts in the ring so it holds = the sheath in the ring. I had to bend these out and put the old sheath = back in. I put it back together and it works great. All of this took = no longer than about 20 minutes. Tomorrow I am going to work on the = passenger seat and try to get it to work right. It works except you = have to help it recline. I will let everyone know how this works out, = when completed.

Thanks for the good advice.

Philip
88 735i 5 speed
87 300D

From: "Craig Lovold" <clovold_at_mail.mecc.com> Subject: '88 735i hard starts

'88 735i hard starts

My wifes car has a very frustrating (and embarrassing) problem. It must be fairly warm out (75 degrees or better, high humidity makes it worse). When the car is driven enough to fully warm it up and then let stand for about
an hour (like at her aerobics) it is very hard to start. Turn the key, it starts to catch and then kills. It does this about 7-10 times before it will
finally keep running. This will only happen if the car has been sitting for 45-70 minutes, outside that range it starts fine. My wife is fed up with it. Could it be vapor lock? what is vapor lock? Why do
you have to let it sit 45 minutes before you have a problem?

TIA for your help.

Craig Lovold

Craig Lovold wrote about hard starts when the 735 is hot/warm.

I'd check in order the idle stabilizer and the coolant temperature sensor. Pull the stabilizer (from the passenger side, to the left of the air flow sensor) and spray it with carb cleaner or brake cleaner. The specs for the resistance of the temperature sensor are in the Haynes 3/5 Series Book.

Good luck,

Doug

From: "KEVIN MOAK" <kmoak_at_va.gibbscox.com>

     On another topic, I noticed FRESH oil around the tip of the timing
     chain tensioner anti-tampering cover this weekend.  Wiped it off, and
     it was back the next day.  Very slight leak, but is it possible that
     it is coming from another source besides the tensioner?  I can't
     really get a good look at that area without taking a LOT of stuff off
     of the car.  There's an oil spot b
     below this area on one of the
     underside mud/stone guards, so it's been leaking for awhile, but I'm
     not down on oil in the crankcase, so it is a very minor slow leak.
     Still, it IS a leak, and since this isn't a British sports car, I
     don't expect ANY sort of a leak.  Any thoughts or ideas?

Kevin,

There is an o-ring inside the belt tensioner that hardens over time. I replaced the o-ring in my 750 and the leak went away. To replace it you need to buy, the o-ring, crush washer, and the anti-tampering plastic cover. The only hard part is putting bolt back because of the spring. You have to have a strong arm to push back the spring while turning the bolt to bite into the thread. If you need more info, just drop me an mail.

Reuben
reubenr_at_netcom.com
89 750iL

I haven't tracked it down recently on the 750 (did about 2 years ago) but my other BMWs have it clipped near the center Kidneys - either directly or on the top of the bumper.

C. Koch

>      not down on oil in the crankcase, so it is a very minor slow leak.
>      Still, it IS a leak, and since this isn't a British sports car, I
>      don't expect ANY sort of a leak.  Any thoughts or ideas?

>
Every BMW I've owned leaks (although as you said, not nearly as bad as English cars). Usually temp or pressure sensors. But most often the (damn) hydraulics. Those rinky dink aluminum rings are lousy! I've replaced so many trying to stop drips - and almost always without success. By the way, the fluid may end up anywhere: check it out.

I have found that most ordinary engine seals on BMWs are much better than average - most can be reused over and over unless abused by overtorquing.

C. Koch

Christopher Koch wrote:
>
> The local chapter (Boca Raton, Florida) steered me to their favorite > local shop who had an ex-Dealer technician who told me "we replace these > like popcorn" and "they failed often during something as simple as the > walnut-shell valve cleaning procedure" and "don't run the car in park or > neutral more than a minute or two - the transmission will overheat" and > "ZF made several revisions - be sure you buy the latest". >
There was something in the technical notes or letters of Roundel mid-year in 1994 about this. There apparently is a problem associated with running the transmission at elevated RPM in neutral which will cause nearly immediate failure of the transmission. This apprently was happening during the emission tests required in some states. The text there went on to describe a procedure (can't remember if it was a BMW procedure or what) to keep from destroying the transmission. It had to do with limiting the amount of time the engine was kept at elevated RPM in neutral.

The more I think about it the more I seem to remember that the problem involved all 7's, not just 735's.

Doug Donsbach - dld_at_symtec.com - Knoxville, TN '88 735i BMW CCA - '88 951 PCA

I ran out of time giving my ZF feedback above. Yes, can you imagine such advice as "limiting the amount of time to less than 60 seconds"? How absurd! As if transmissions were new devices and hadn't been popular since the fifties. But, take heed, and don't violate this limit.

Since my 1987 735i ZF HP22 failed, I have asked every BMW mechanic I've encountered (Oktoberfest, Concours, Meetings, etc.) about the mighty ZF used in our sevens (until replaced by the current ZF five-speed). They all have readily admitted the (very) high failure rate.

I wrote a letter to BMW NA about this and they replied that there was no significant failure rate on the ZF transmission. Either they are in acute denial or most BMW owners are sharp enough not to pay $3500 or more at the Dealer - prefering the little local tranny shop...

The second thing I did after purchasing my 750iL was acquiring a ZF HP24 tranny out of a wreaked 1992 750iL (by the way, the engine was transplanted into a 635CSi!). It now occupies my engine stand, ready for the day it needs to be pressed into service. I also immediately drained (repeatedly) and ran twelve quarts of Amsoil synthetic through the original ZF. I still keep a close eye on the fluid, but all has been well so far...

Christopher Koch

On Mon, 25 Mar 1996 bmw-750_at_transarc.com wrote:

> From: powdah_at_mainelink.net (David Leonard) > Subject: e32 tranny
>
> It seems to me that whether or not the car is in gear has little to do with
> fluid heating, because as I see it the torque converter spins either way, > and this is the primary source of fluid heat. True, the tranny in neutral > should heat less, as the gears are freewheeling rather than doing work, but
> never the less there is no cooling airflow. >
> I don't know if the cars have an external oil cooler, or just use the pass > through the radiator. Anybody know? Seems like it may be worth adding one.
>
> Dave Leonard
> 88 e32 735ia
> 107k

Dear Dave,

I doubt very much if "air cooling", that is, the flow of air past the transmission at speed has any basis in reality. First, the transmission has little if any cooling "fin" to increase surface area. I just looked at my spare in the basement and all "fins" are structural (increase rigidity of case). Plus the tranny is downstream of an engine that is belching heat.

Our BMWs have a heat exchanger built into the radiator - just like American cars. Therefore, this warms up a cold tranny and (somewhat) cools a hot one.

I further doubt if the prior history of any BMW has any effect on transmission life. Most BMWs are serviced at the Dealer for the first 70K miles by the (wealthy) first owner and Dealers usually change the trans oil every 30K (some of you may argue this - but most every BMW I've considered to purchase had these
services on the service invoices).

The ZF was poorly designed - that is all one can conclude. I have NEVER had a problem with any automatic transmissioned vehicle before (I'm on #48)! I NEVER had to turn off an idling engine running the A/C before my BMWs! I NEVER
had to watch elevated rpms over time when servicing my cars!

Yours, Chris Koch
>

Found this on the digest.
I think its relevant:

Well, Im not sure about the bulletin on the ZF trans, but I do know the problem...Its after the car is put in a drive gear,then into neutral or park, that if you rev the engine, it will burn out the trans. The cause is that this particular trans keeps fluid pressure on, even though youve shifted
to neutral. This causes the front A clutch pack to basically wear itself out,
very fast, since the clutches will be taking all of the engine power and no transfer to gears. My friend at work fixed on of these ZFs by replacing the front A clutch pack. The trans was saveable.

BTW this also pertains to Volvos, Jaguars and other cars that have this ZF trans. Ive seen many BMWs at work come in with only reverse gear, and
no forward because of a burnt out trans.

The only way to rev your engine after putting it into gear fairly safely is to stop the engine for 30 to 60 seconds, then restart, put dont put
into gear. The ZF in my 87 Volvo is still good and shifts nice a crisp, if a bit firm. Hope this helps.

BTW, I work at BMW of Honolulu, but my comments and suggestions are from my experience and not those of BMW NA or BMW of Honolulu.

Mahalo Alan Chung 91 525iA Dinan Chipped

David found this on the digest:
>>>Well, Im not sure about the bulletin on the ZF trans, but I do know the problem...Its after the car is put in a drive gear,then into neutral or park, that if you rev the engine, it will burn out the trans. The cause is that this particular trans keeps fluid pressure on, even though youve shifted
to neutral. This causes the front A clutch pack to basically wear itself out,
very fast, since the clutches will be taking all of the engine power and no transfer to gears. My friend at work fixed on of these ZFs by replacing the front A clutch pack. The trans was saveable.....

The only way to rev your engine after putting it into gear fairly safely is to stop the engine for 30 to 60 seconds, then restart, put dont put
into gear. The ZF in my 87 Volvo is still good and shifts nice a crisp, if a bit firm. Hope this helps.<<<

Thanks a lot David for fowarding this to our list; I really appreciate it. It confirms what my mechanic has told me about high pressure in neutral/park ruining the transmission.

The way I interpret all of this is that the "solution" that described above assumes that the clutch plates are not pressurized by the pump while the trans is in neutral or park. Consequently, the clutch failure occurs not because the pump is still directly pressurizing the plates in neutral/park but because the pressurization that occurred while the trans was in a drive gear was not bled off when neutral/park was subsequently selected.

This would lead one to conclude that even letting the engine idle at 800 rpm in park or neutral after running a drive gear would cause premature wear of the clutch plates which are still pressurized at the same pressure that existed when the trans was in gear.

Anyone have comments on this to the contrary? Although some might say we're beating this topic to death, I think we're finally understanding the exact circumstance causing transmission failure during high idle smog checks. I feel better. Do you feel better?

Brian
1991 750iL (in the shop, again)

Well, where this last left off, the dealer where I had my car inspected, had admitted wrong doing.

The next time I spoke with them, they had a completely different attitude about their wrong doing. They sent me a copy of a transmission service bulletin (I don't have the number, but I will post more about it at a later date if desired). The service bulletin describes proper emissions testing procedures for 1985-1987 BMW's with the 4-speed automatic transmission.

The basic gist of the bulletin, is that it is permissible to operate the engine at speeds up to 2000 RPM for up to 90 seconds with the transmission in park (not neutral) ONLY if the engine has not been running for at least 30 seconds, and ONLY if the transmission has not been shifted into any gear other than park.

Once the transmission is shifted into any gear (forward or reverse) the clutches are pressurized, and stay pressurized until the engine is turned off for at least 30 seconds.

PLEASE NOTE: This particular transmission problem does not only happen during emissions inspection. It can happen during AC recharging, engine diagnosis, etc. It can happen any time that the engine must be operated at elevated RPM for more than 90 seconds!

My situation now is that the dealer is offering to redo the state inspection with me watching, but they do claim that they tested the car correctly the first time, and hence caused no damage to my transmission. I see no justifiable reason to do this, as it can only cause more wear and tear on my car.

Since I have received the bulletin, I at least feel better about the situation. I am trying to get the dealer to try and find a bulletin that is specifically about 1989 model cars.

(Prakash: Does your Alldata CD have any bulletins/procedures for emissions testing of automatic transmission cars?)

My question for you folks is: Does anyone have any official written information that would contradict what the dealer has told me?

Thanks for all of your help and support.

Jeff Moser

Brian wrote;
"This would lead one to conclude that even letting the engine idle at 800 rpm
in park or neutral after running a drive gear would cause premature wear of the clutch plates which are still pressurized at the same pressure that existed when the trans was in gear."

I am not sure this is the case, because even if the clutches are pumped up, the torque converter slips mightily at 800 rpms, where when it is revved, it approaches its stall speed, and then becomes much more of a solid coupling between the engine and transmission. This would certainly dump a lot more power into the clutch packs than when idling at 800. At Idle the heat buildup is being dumped into the transmission fluid, and cooled. When revved, the power is going int the clutches, and the heat is staying there , and rather than being dumped harmlessly, it is burning the friction material of the bands.

I have no real knowlege of what the stall speed of the e32 converter is, but I know for small block Chevys you buy hi performance converters w/ a 2500 rpm stall speed for hi-po applications.

My understanding is that the stall speed is the theoretical speed that the engine would stall at WOT, if the output shaft were held stationary. I could be all wet with this theory however, you never know! If anyone can enlighten me on this, please do so.

Dave Leonard

To everyone: excuse the bandwidth but I wanted a big finish to the continuing saga of the flawed BMW transmission (call it the Cecil de Mille syndrome).

Jeff Moser <jrmoser_at_nando.net> wrote:
>>>The service bulletin describes proper emissions testing procedures for 1985-1987 BMW's with the 4-speed automatic transmission.

The basic gist of the bulletin, is that it is permissible to operate the engine at speeds up to 2000 RPM for up to 90 seconds with the transmission in park (not neutral) ONLY if the engine has not been running for at least 30 seconds, and ONLY if the transmission has not been shifted into any gear other than park.

Once the transmission is shifted into any gear (forward or reverse) the clutches are pressurized, and stay pressurized until the engine is turned off for at least 30 seconds......

My situation now is that the dealer is offering to redo the state inspection with me watching, but they do claim that they tested the car correctly the first time, and hence caused no damage to my transmission. I see no justifiable reason to do this, as it can only cause more wear and tear on my car. >>>

>From BrianM (BrianM_at_ix.netcom.com)
Jeff,

I checked my AllData info and could find no service bulletins regarding this issue. My disk only covers 1991 BMW's so this doesn't necessarily mean that a relavant bulletin does not exist.

I did contact the BMW mechanic, Alan Chung, in Hawaii who had posted an entry in the digest pertaining to this transmission issue (I think it was Dave who originally posted a copy of this to our list).

>>>>{Part of whate Alan originally wrote in the digest: > The only way to rev your engine (in neutral) after putting it into gear > fairly safely is to stop the engine for 30 to 60 seconds, then restart, but
> don't put into gear.<<<

I replied to him:
> The way I interpret all of this is that your solution assumes that the > clutch plates are not pressurized by the pump while the trans is in neutral
> or park. Consequently, without your solution, clutch failure occurs not > because the pump is still directly pressurizing the plates in neutral/park > but because the pressurization that occurred while the trans was in a drive
> gear was not bled off when neutral/park was subsequently selected. >
> This would lead me to conclude that even letting the engine idle at 800 rpm
> in park or neutral after running a drive gear would cause premature wear of
> the clutch plates which are still pressurized at the same pressure that > existed when the trans was in gear.

Alan replied to my inquiry:

>>>Let me follow up as best I can...Yes the trans will be pressurized >after putting it into a gear. If neutral is then selected, the pressure does >not bleed off sufficiently. Your explanation is very good. Revving the engine >makes it worse because it puts more load on the clutches. > The 750s have the ZF 4HP24, which is a heavy dutier version of the >hp22. However, its design is the same and it is afflicted with the burnout >problem. I have seen 750s come in the shop with this problem, although mostly
>88-89's with high mileage. You can eventually burn out the trans while idling
>at normal idle as well too.
> I was in this 750 that was in for trans repair and I started it up when >it was cold, put it in drive and it worked. Then, I let it idle for awhile and >went back and put it in drive and no go. So I turned the engine off, then >restarted it and drive worked again. So idling for prolonged periods can burn >the trans as well.
> I think that this problem made the ZF a poor transmission. Other than >that it is pretty strong and all.
> Well, I hope this helps, let me know if you have anymore questions. >Mahalo Alan Chung 91 525iA Honolulu, HI >>>

Jeff,
I agree with you - redoing the emissions test will serve no purpose. As I mentioned before, however, you need to drop the transmission pan to check for debris. If the clutches were overheated you should find a lot of clutch material in the bottom of the pan. If the pan is clean (and the dealer didn't have a chance to clean it before you looked at it) I wouldn't worry about it.

In conclusion, we have it from two sources (your dealer and Alan) that we must stop the car, wait for at least 30 seconds, and then restart the car before running at 2000 to 3000 rpm in neutral or park. Engaging a drive gear at any time requires that the process be repeated due to hydralic pressure not bleeding off when the trans goes from a drive gear to neutral/park.

After all of this I think we can safely assume that we have gotten a handle on what is actually going wrong inside the transmission when emission testing (and other procedures like A/C charging) is done. By knowing exactly what is going wrong we now know how to avoid placing the transmission in jeopardy.

Also, based on the service bulletin you mentioned the problem seems to be restricted to pre 1990 transmissions although I'm going to treat my '91 as if it also has this failing. Despite assurances to the contrary, I also plan to play it safe during my car's next emissions test and put the rear wheels in the air and leave the transmission in drive. Afterall, it doesn't really cost anything to be too careful.

Jeff, could you please give me the number of the service bulletin in question when you get the chance. Thanks!

Brian
1991 750iL

Well, as the subject says, this is the final chapter to the automatic transmission story. I am finally convinced that no damage was done to my transmission during the emissions tests. Since it is time to change the ATF anyway, I will check out the inside of the oil pan soon, just to be absolutely absolutely positively convinced.

As I said before, the dealer provided me with a copy of service bulletin # 24 01 91 (3196) dated June 1991. BMW NA called me today, and comfirmed what the dealer had told me. Since the dealer freely gave me a copy of the bulletin, I am going to post it here as follows. Thanks for everybodys help and suggestions. NOW: Lets get on with some new and different topics!

Subject: Transmisison Failure during Exhaust Emission Testing

Models: All 1984, 1985, 1986 with 4-speed automatic transmission, 1987 635CSi, 735i, and L7.

Situation: There have been reported isolated cases of automatic transmissions failing during a High Idle Exhaust Emissions Check. The failures have resulted from a preconditioning procedure where the engine is held at high rpm for a prolonged period of time. The following applies to all states which have a High Idle Exhaust Emission Check.

As the internal transmission components experience normal wear over time, the possibility of transmission damage exists if the vehicle is operated for extended periods of time at high rpm in PARK or Neutral. Such operation does not constitute normal operating conditions. If, in exceptional cases such as A/C recharging, injector cleaning, charging system tests, or emissions testing, vehicle operation at high rpm in PARK or Neutral is required the following setup procedure must be performed prior to beginning such operations.

Solution: The emissions test must be conducted with the engine at operating temperature. If the engine is not at operating temperature prior to beginning the test, it is recommended that the vehicle be driven for a short period of time to bring the engine to operating temperature. DO NOT run the vehicle at high idle to achieve operating temperature.

Once the engine has reached operating temperature, the following pretest procedure must be performed BEFORE testing begins.

Setup Procedure for I/M Emission Test

1. Shift to PARK.
2. Turn engine OFF.
3. Wait at least 30 seconds.
4. Restart engine, LEAVE TRANSMISSION IN PARK. After the engine is started, DO NOT move the gear shift selector through the Forward or Reverse gears before or during the test sequence. DO NOT EXCEED 2000 RPM.
5. Begin emissions test procedure.
6. If the vehicle fails the emission test, some states allow for an extended pre-conditioning before the repeat test. In this case the following procedure should be adhered to.

Precondition Procedure

1. Shift into PARK and turn the engine OFF for 30 seconds.
2. Restart engine, LEAVE TRANSMISSION IN PARK.
3. Engine may be preconditioned at a maximum of 2000 RPM for up to 90 seconds, at which time the repeat test must begin.

If the above steps are not followed, serious transmission damage can result.

Note: Due to the unusual nature of the emissions check, this type of failure does not take place under normal operating conditions.

And that's all she wrote.

Jeff Moser

Hi Folks, (Can you tell that I am from the South?)

I finally got around to changing the ATF in my car over the weekend. I drained out the old fluid which was a pinkish-brown color and smelled slightly burned. I then proceeded to remove the oil pan to take a look inside. I was kind of nervous, due to the recent emissions test fiasco that the dealer put my car through. When I looked into the oil pan, I was delighted to see no debris in the pan whatsover. Not metal particles, not clutch particles, nothing, nada, zip! The outside of the filter was coated with a fine layer of clutch particles and the filter screen was not clogged.

Anyway, I put on the new filter and pan gasket and buttoned it back up. I filled it with Mobil 1 synthetic ATF. I went for a test drive, and I noticed a definite improvement in the operation of the transmission. Although I was not experiencing any operational problems with the transmission before, the new fluid made the transmission seem to operate much better. I don't know exactly how to describe the differences, but the transmission now feels more "solid" and "smooth". The car seems to accelerate from a standstill much more stongly than it did before, even though it worked perfectly fine before.

One other definite improvement that I noticed is that the annoying driveline shudder that had been occuring in my car, ever since I have owned it, in the speed range of 0-20 MPH is now GONE! I was expecting to have to replace the drive shaft to cure this problem.

Now I don't know exactly how to attribute the differences in operation. Did the synthetic ATF cause the improvement, or did just changing the fluid in general cause the improvement? After thinking about it, I tend to believe that the synthetic ATF caused the difference because the car has had the driveline shudder for quite a while, even when the original transmission fluid was clean(er). Anyway, since I am still running at least a half and half mixture of synthetic/dirty fluid, I am going to drain the fluid again in a week or so, and put in some more Mobil 1 to improve the synthetic/dirty fluid ratio.

I know that this is getting long, but while on this subject, I recently purchased an ATSG ZF 4HP22 rebuild manual from the Transmission Exchange (1-800-776-1191) for $12.00. Of course, the book describes how to rebuild the beast, but more importantly, it describes some modifications that must be made to these transmissions to correct "Premature Forward Clutch Failure".

The problem is that the seals or the bore of the main input shaft can wear, and cause fluid to leak from the torque converter directly into the forward clutch (clutch A), causing the clutch to activate. Clutch activation in these circumstances can cause the clutch to fry and/or the car to try to move forward when in neutral if the engine is accelerated above idle. To correct the problem, one of the shaft seals must be changed from steel to teflon, a 0.045" diameter hole must be drilled into the forward clutch A piston (to bleed off any misapplied pressure), and the forward clutch orifice in the valve body must be enlarged (to compensate for the lost pressure due to the 0.045" hole in the piston). The manual doesn't say what years of transmissions are affected by this problem. I remember someone from this digest describing a similiar procedure that was done when their transmission was rebuilt (Chris?). I also know that BMW had a transmission recall in the 1986 timeframe for a similiar problem.

Also, one last bit of trivia: Did anyone know that the ZF 4HP22 transmission was used in 1985 Lincoln Diesels?

Jeff Moser

My 1989 735i has the famous steering wheel shimmy when braking in the 60-45 MPH speed range. The car has had this shimmy ever since I have owned it.

Right after I bought the car, I thought that the problem was warped brake rotors, so I had the front rotors turned (I know, I know). The problem went away for a while, so I am pretty sure that the problem is really the brake rotors, and I am thinking about replacing them.

I also thought that maybe the less than perfect tires that were on the car were also part of the problem. I finally had new tires put on the car and the problem is still there.

I just wanted to run this past you experts and see what your opinion is. I am planning on ordering a couple of brake rotors, and a new set of pads in hopes of curing this problem.

Is there anything else that I should be checking? Any good (and inexpensive) sources for rotors and pads?

BTW: The car has new Thrust bushings, and I have a new right side upper control arm that I am going to have installed also.

Hi,
Does anyone know this device under my 750, -cylindrical shape attached to the power steering reservoir, called and how much it cost to replace it. It leaks power steering fluid. Thanks in advance. Peter

Peter;

I had this replaced, my mechanic called it an accumulator, it boosts the power steering
and the brakes. I was charged $561.00 and after 2 days the reservoir overflowed
all over my garage floor, my BMW dealer would have charged me the same and they would have tried to resolve the problem, my mechanic said this was just a
coincidence and to monitor the situation? If anyone cares I just had an evaporator
and drier and a hose replaced for only $2,250.00, oh the wonders of owning one of these beautiful automobiles.

Jack
computerconsultants, inc.
cocoinc_at_shadow.net
FAX (954)927-5838 VOICE (954)927-1412

Richard asks:

>Subject: E28 ZF Power steering box overhaul? >
>I have a 1986 525iSE which has a certain amount of slop on the powersteer= >ing box input shaft. When the steering is turned a quarter of the way fro= >m the centre position, it can be rocked 1" left and right without moving = >the roadwheels.
>
>I carried out the usual preload adjustment by slackening the 17mm locknut= > on the top of the steering box and turning the screw in the centre of th= >e nut in 1/4 of a turn. This got rid of the play, but leaves a dead/heavy= > feeling in the centre area of the steering plane.

This is BAD - it means you've overadjusted - and will destroy the bearings in the steering box.. loosen tonight! The real procedure for setting the bearing preload in the box involves removing it from the car and using a precision torque indicator on the input shaft while adjusting it. There is also (at least on mine) a secondary adjustment for the input shaft end-play which is only accessable with the box out of the car.

>QUESTIONS:
>
>Are their any user-serviceable parts in the steering box?

Not really.

>Whats behind the metal plate bolted on top?

The bearing and bearing adjuster which adjusts the output shaft freeplay

>Is there a part inside I can sandpaper to even the wear?

Not unless you're a miracle worker. These are recirculating ball steering boxes - somewhat sophisticated. Not agreeable to home-mechanic intervention.

>How does power steering work?

Very nicely when it works correctly - it's basically an "assist" not a full-power steering system. For real details I'd suggest finding a factory manual.

>Thanks in advance for any help.

My only advice is that perhaps you would be best looking for a low-milage replacement box. By the time it is torn down and all the parts replaced and adjusted correctly - you're looking at serious $$$. Luckily they are not a high failure rate item - so used cost should be reasonable. I am not certain (Phil Marx??) - but the same box may have been used in other models ('70s 7-series??).

If it was me - and I'll tear almost anything apart.. I'd look for a good used one.

Don

PS: Due to the design of the box (recirculating ball and/or gear/sector) - some freeplay is NORMAL when not on center. It's the nature of the beast. 1" at 1/4 turn does sound excessive.. so you probably are due for a steering box - but heck, it's less than a months payment for a new Bimmer..

Don Eilenberger
deilenberger_at_monmouth.com

Dear Dan Lai,

I noticed in your subscription bio that you have had trouble with your power steering pump/s.

Mine was never quiet but was bearable as a background noise (my passengers just thought it was a normal BMW sound). However, it has recently become louder and louder. At idle and low speeds it is by far the most predominate sound in the car.

I have been shopping this pump the past week and am astounded that this $80 pump costs as much as $685 for a rebuilt (the low so far is $197 plus core at Eurasian Parts). I haven't even considered new.

I am wondering if a rebuilt will be quieter (my current pump works fine) or will be just rebuilt with new seals and bearings...

Any thoughts?

Yours,

--
Christopher Koch
Tel: (716) 856-5245 Fax: (716) 854-1184

This reply to Alan turned into such a practical treatise on strut replacement that I decided to waste the bandwidth and post it on the digests in hopes of helping out some other people. Besides, it makes me feel important.
I know someone will give me a hard time for having Bilsteins up front, and Boges in the back. All I can say is " I know, I Know. The real pproblem is the lifetime warranty on the Boges and my inherent cheapness. Will I buy Bilsteins for the back? I dunno, seems to handle real well this way and I'm so cheap.

>>At 10:23 PM 4/11/96 -0400, David wrote: >>>Hey I've got an 88 735 e 32 w/ bilstiens in the front, and boges in >>>rear...Low on cash when I bought the rears. I paid 210.00 for the Bilstein
>>>HDs at Bavarian Auto svc. and wish I had them on the back. The valving is
>>>quite stiff, but the ride is sweet even in Maine over the frost heaves. I'd
>>>recommend them to you the ride isn't harsh, the damping is firm . >>Alan:
>>Bavarian Auto Service lists the Bilsteins at about $222 for the front pair,
>>and $199.90 for the rear pair, so I guess that prices have gone up a little.
>>I live in New Hampshire, so I've got the same frost heaves and pot holes that
>>you do.
>>David:
>>>The Boges aren't a bad choice either, but after putting in the Bilstiens >>>I'll never go back. It took me about 5 hrs to change the fronts, but I had
>>>air tools and torches and a strut compresser. The rotors and calipers have
>>>to come off first.
>>Alan:
>>I have those tools, and I need to do a brake job anyway. I was going to have
>>the mechanic do it, but upon thinking about it, this is not rocket science. I
>>DO have some questions, though. Did you remove the calipers completly, or >>just take them off the rotor and hang them out of the way (with the brake line
>>still attached)? Also, did you have to take the entire strut assembly out of
>>the car, or were you able to do the trick of only disconnecting the top of the
>>strut and then swinging the strut out the wheel well? I've been told that if
>>this is possible, then I can save a lot of time.

>>I was going to have the car aligned, (just switched back to summer tires) and
>>the mechanic noticed the leaking strut, so for obvious reasons, he didn't do it.
>>After I replace the struts and brakes, I'll have the shop do the alignment and a
>>brake fluid flush (I hate messing with brake fluid...its worth the $50 to me to
>>have them do it).
>>
>>David:
>>>The rears took a total of 1.5 hrs to change. >>Alan:
>>I took a look in the trunk and saw where the strut tops are. How the hell do
>>you get to the bolts? Do you have to remove the back seat? It looks like you
>>could remove the parcel shelf and speakers and go though there. Any insight?
>>
>>
David:

Replys to questions.

I think you have to remove the struts from the car. I changed my 2002 struts on the car one time, but you really have to use a lot of brute force and ignorance to remove the cap nuts on the struts... you could really do some paint/bodywork damage if(when?)you fucked up!!!

I removed the calipers and let them hang from the hose like you're not supposed to do. Actually I propped them up on the suspension and they only fell off and hung by the hose 30 or 40 times. The struts unbolt at the bottom with big bolts. You have to take the ABS sensor and brake pad wires off, as well as the brake hose to strut mount bolts(make sure that you don't twist the brake hoses on re assy. I think I had to crack the flexible hose to hard pipe line nut to un twist the brake hose . A good set of Snap-on Metric wrenches gose a long way here, as does a 1/2" Impact wrench.

I have a K-D strut compresser, 30 bucks 15 years ago.. seemed like a lot of cash then.. paid for itself many times now, although I confess that I just paid a mechanic $225 to change the front struts in the wife's Mercury Sable! ( Shame on me I only wrench Bimmers, Airplanes, and Boats.. Not enough time to do it all, but it (paying someone) does feel like cheating.)

Tighten the spring compresser evenly, don't point the springs at your testes (required car guy sexist comment, ladies don't aim them at any critical body parts either!) or your face!!! (no I didn't learn this particular lesson the hard way) Then use an impact wrench to remove the spring and set it aside gingerly.
Sometimes the compresser can slip around on the spring and the two parts will end up next to each other. This usually happens when you are whacking them with a hammer to "even them out"....what a dipshit...un-do them and take another bite, it happens.

I cut through the caps (Rusted on) with a die grinder, parrallel to the strut shaft on both sides of the strut (careful not to cut the strut body , just the cap) , I used a 2" abrasive cutoff wheel. I then heated them w/ acetelyne torch, (carful not to melt anything) and removed them with a big-ass stillson pipe wrench and some motherfucking huge waterpump pliers. It takes a fair amount of hassleing with the strut compresser to get the springs off, again you could really hammer the paint in this operation too if you tried to do this on the car. The Bilsteins have new strut cap nuts as part of the pkg.

Note, I fucked this up...you won't because I already did and am going to share this with you. The Bilstiens are Internally bump stopped. You don't need to (can't actually) re-use the bump stops. So, you're sitting there saying to yourself "I wonder if I need to re-use the dish washers that the stock bump stops use to bottom out on...Nah.. no bump stops= dished washers= extra parts." WRONG!!!!!!!!! they rattled. You need these to shim the strut shaft so it doesn't move in the upper support bearing. (NO I didn't thke the goddamned things apart again, I took an impact wrench, and with the weight of the car on the tires, removed the strut shaft nuts and sneaked a washer in on top...crude but effective.).

Note: re assembly is reverse of...well you know. Things to watch out for... make sure that you have the rubber spring buffers in place and the ends of the spring properly seated. It sucks compressing the springs twice.. how do I know this.. well, you know how it goes.. I guess patience is a virtue.

Rear struts are a picnic , comparatively speaking. Take the bottom of the seat out, and then remove the seat back and pick up the parcel shelf cover to get to the top mounts. (I think) can't quite remember.

BTW the Chilton's All BMW's book, 1970-1988, avalable at Bavarian auto has this procedure in it. It really is surprisingly good, considering it covers all models and years.

I hope I haven't scared you off this project.. It is one of the more satisfying DIY projects you can do. I would be a good time to change to lowered springs if you want to turn your car into a boy racer ride. I opted not to, as lots O' suspension travel is good in New England. I didn't want to loosen any fillings. I did lower the front end 1/4 " with thinner spring bushings from Bavarian... Almost unnoticeable.

The other note is that It takes significantly longer on the first strut than the second....you really learn from experience.. I can do a VW rabbit in about 45 min a side now, and I m not a professional mechanic.

I just bought a set of Pirelli t4000 tires, v rated, 60,000 mi treadware warranty at NTW
for $640 balanced, on the car, all warrants and lifetime balance. Then I drove 85 mph in super heavy rain and liked it( no hydroplaning, quiet etc. Didn't hit anything either! COOL!)

Time will tell how I like them but my initial impression is good.

>88 e32
>'55 Piper PA-22
>84 Grand Wagoneer(so big!)
>89 smallblock powered 21'Wellcraft
>Notice I didn't mention the Mercury Sable...cheap, and lots of boneyard parts avalable down the street.

Any resident experts out there? I've got a 81 745i with anti-lock that are mush.
Is there an air bleed on the anti-lock assembly? What's the official service proceedure for bleeding these things? Please e-mail directly any reply's because I'm burried and it will get lost otherwise!

On Sat, 13 Apr 1996 bmw-750_at_transarc.com wrote:

> Brian wrote:
>
> Another problem I've run into is a strange metallic clicking noise that > occurs under hard cornering to the right..... The harder I corner the > louder the clicking.
>
> Thanks for the advice but I neglected to mention that the noise seems to be
> coming from the right front wheel area. Any more advice would be appreciated
> from anyone that has a clue to what this might be. >
> The Other Brian
> 1991 750iL
>
Dear Brian,

One of our local chapter members had this happen on her 735i - and it turned out to be some road debris wrapped around her anti-lock sensor mechanism on the passenger front tire. The sensor is somewhat like a gear sprocket from a bicycle with an inductive pickup.

Unfortunately in her case, she waited too long (about two weeks) and the debris chewed up the "gear sprocket" and damaged the sensor itself. Both had to be replaced.

Chris Koch

> I have a noise that seems to be coming from the left front part of the engine
> compartment, whenever I hold the brake pedal down. It's an intermittent clicking
> sound that can be felt on the brake pedal. Is this a power assist servo problem?
> Any clues?
>
> Jack
>
Dear Jack,

Just wish to confirm that my 750iL has had this same noise during my entire ownership. I tried three Dealerships and the gurus at the Oktoberfest without finding an explanation...

I figure it has something to do with the servotronic steering or perhaps the braking system (pressure regulator?). I too feel it in the pedal.

Sure is irritating - especially since only you and I seem to hear it!!!

Chris Koch

>
> From: Guy Therien <Guy_Therien_at_ccm2.hf.intel.com> > Subject: Brake Pressure Warning Message >
> I am getting a "BREAK PRESSURE" message in the MID of my 91 750iL. Despite the
> owners manual, it's not clear to me what can cause this. There are no mechanical
> symptoms, the brakes work fine. I thought that I might be low on the brake > booster / power steering fluid. Does anyone know what type of fluid to buy and
> how to check the fluid level? It wasn't completely obvious to me. >
> Guy
>

My '88 750iL had the same symptom. The problem was due to the defective brake
pressure switch. The parts replaced are:

     61-31-1-362-977     Thrust Switch  $23.63
     34-33-1-150-922 Switch/Oil Pre     $22.83

I am no mechanics, the above parts number and prices were how much the dealer
charged me.

-fredv-

BTW, the diagnostics and labor + the parts = 89.06.

Doug,

The following is a repost of an answer that I gave a few weeks ago about the HVAC fan control box. If I can help you further, let me know.

Jeff Moser

>
>I have had a quick look at my ETM (1989 E32), and it seems that the resistor that you are talking about is really a thing called a "Final Stage Unit". The "FSU" is actually a little more than just a plain resistor. It contains a transistor and associated electronics that allow you to have infinitely variable fan speed, and it also contains a relay which kicks in when you turn the fan switch all the way on. If you are interested, it is located behind the LEFT footwell (console) panel of the passenger side, and it appears to be on the order of a pack of cigarettes in size. >
>(All of the above assumes that your 1988 is the same as my 1989.) >
>If you do have it replaced, I would love to have the defective piece if your dealer will give it to you. Being an EE, I just love looking inside these "little black boxes".
>
>Jeff Moser

Doug,

I think I was the one who told you about the location of the HVAC fan control. I hadn't actually seen it myself when I described it's location to you. Since that time, I have actually removed the one from my car (in search of the non-existent microfilter), so maybe I can help further.

Remove the left side console panel in the passenger footwell. (You may need to remove the glovebox also). In the area of the removed panel, you should see a wiring harness. Trace the harness toward the firewall to the connectors, there should be three. Two connectors plug into the HVAC main control unit which is located near the firewall. The third connector plugs into the HVAC fan control, which is located just behind the main control unit. (Hint: The fan control connector is a different type of connector than the other two).

Now, hopefully from the description above you have found the HVAC fan control. Remove the harness connector from the fan control. The only part of the fan control that is visible at this point is just the end, as most of it is buried inside the evaporator housing. Remove the two screws about 1 to 1 1/2 inches above and below the connector on the fan control, and slide it out of the evaporator housing. When removed it is an aluminum heatsink with 4 power transistors on it which is about a foot or so long.

Hope this helps.

Jeff Moser

Hi Doug,

Regarding the fan module....look on the passenger side after you drop or remove the glove box. You will see a 3'' oval/rectangle sized plastic unit secured with 2 phillips head screws and a wire connector going to it. Remove the screws and pull the unit out towards the passenger door. The unit is a giant circuit board with power transistors on it about 2 feet long??? I found bad solder joints on my unit and resoldered it( it used to only have the fan on high) It worked for about 2 years and last week it fritzed again...now my fan wont shut off....Oh weel so much for the Gremlins from Stuttgart. Ed

Ed Berroth
Portland,Or.

So I have this blower which has two speeds, full on and slightly less than full on.

With help from the list I locate and yank the blower control. Circuit board with a major heat sink. Little analog bits and 4 big power transistors.
The problem was one of the transistors had shorted collector to emitter. This was obvious when I drilled out the rivets holding the assembly together and found the back of one of the transistors burned brown. The failure was caused, I suspect, by a quality problem in manufacture. It seems whatever they used to coat the curcuit board got between the transistor-to-heat sink thermal path and the transistor just couldn't get rid of that much heat by itself.

The transistors are darlington, I suspect, bacause the base current for each transistor is supplied through a 4.7K resistor. When the motor is running at near full speed the current through the board is about 12A, so each transistor carries about 3A of that. So there has to be a pretty big beta given that the base current is probably only about 2.5mA.

The power transistors have been potted in some major strong epoxy or I would yank them all and replace them, using some good heat sink grease and threaded fasteners instead of the Al rivets the factory used.

Instead, I ordered a replacement board from Programa. $190 plus $50 core charge. As a temporary fix I used my dremel tool to cut through the epoxy to cut the leads of the offending transistor. Works fine now but I'm sure one of the other transistors will give up pretty soon, due to the increased current load.

While under the dash I was able to see the stepper motor in the area behind the raido. The plastic mount has broken off, which explains why the passenger
side air vent acts funny. I was able to work the broken part out of the dash.
When the new board gets here tomorrow I'll pull the radio and attempt to glue
it back in. Should be a prety large PITA.

I really like this car but there is just way too much complexity and poor quality in the HVAC system. And the seats. And the driveshaft. Pretty good stuff other than that.

Doug

Got the rebuilt fan control board from Programa. They did a nice job of it. Wish I knew how they got the epoxy off of the PCA. Anyway, installed it and it works fine.

Fixed the broken stepper motor mount behind the radio. Now the passenger side A/C is as cool as the driver's side! This was not easy. Several times I almost resorted to ripping the dash off to be able to get clear access to the mount. Not fun at all.

Replace the burned out bulbs in the OBC while I had access to the OBC ejector. Pretty rude of them to wire the bulbs in series so the entire display goes if one bulb burns out. Anyway, it is back in with a good display but I must have disturbed some wiring there as it forgets the date/time and other accumulated information when the car runs for a bit. The folks a Programa think a fuse or a connector is to blame.

Doug

Well it was such a nice day today, I decided to go outside and screw around with the car for a little while. I decided it was time to check the infamous microfilter out and see what condition it was in.

I followed the procedures listed in the E32 repair manual, and removed the glove box, the HVAC control unit, the Final Stage Unit, to get down to the point where the microfilter actually is supposed to be. Lo and behold, it was then that I discovered that my 1989 E32 is NOT equiped with a microfilter! Well, I guess you live and learn. I don't know when the E32's started having microfilters, but my 1989 doesn't.

One interesting thing that I did learn while undertaking the above was that the glovebox does more than just open downward. While trying to remove the gas cylinder from the glove box, I accidentally pulled on the front of the glovebox. The darn thing slid out like a drawer! When the glovebox is pulled out, it makes it a darn lot easier to access the contents. While I am no E32 expert, this is one trick that the car has that I never knew about.

Also, for you folks with HVAC fan troubles, I actually got to see the "$300 Fan Resistor" (Final Stage Unit) today while screwing around looking for the stupid microfilter. This "$300 Resistor" consists of 4 power transistors mounted on an approximate 3" by 12" aluminum heatsink. It also has a small black plastic box and connector on one end. The aluminum heatsink/transistor end is inserted directly into the HVAC ducting and is cooled by the airflow through the duct. It looks like it would be very possible to easily replace these transistors if one went bad. If anyone wants help in trying this, let me know. I once heard someone describe this "Final Stage Unit" as resembling a Sword, and it darn sure does look like one.

Jeff.

(Am I the only E32 owner in the world that did not know how to properly work the glovebox?)

OK, I did some playing around and found out some interesting things. You folks with 750's, follow along and try it yourself and let me know what happens in YOUR car.

First, as a recap, I don't think the left-most HVAC airflow button (on either side) is working properly. The AUTO button and the footwell button work fine, but when I push the left-most button (supposed to send air to ALL outlets), I get a little flow out of the footwell vents, but nothing out of the defrost vents.

OK, first I tried turning the A/C switch off, and guess what, all of a sudden the ALL VENTS button functions fine...air out of all vents. Push the A/C button, and the defrost vents shut off again. So, turned off A/C and then tried the other buttons....in all positions with the A/C off, get small amount of flow out of the defrost vents. Hit A/C, and defrost vents shut off again in all button positions (except defrost setting which works just fine).

Then, I shut off the engine to see what would happen as the vacuum bled off. Well, either that vacuum pump has one hell of a reservoir, or those flap and shutters are operated electrically on the 750's, becasue after 15 minutes of playing around with the engine off (key in position 2), the HVAC vents were still 100% functioning.

So, lots of questions for 750 owners.....

1. Does your system work the same way?
2. Is the system electrically or vacuum activated?
3. If vacuum, how can it operate for 15 minutes after engine shut off. Other cars I've owned with vacuum operated valves, flaps, vents, etc. are only good for about 2-4 airflow changes before all of the vacuum is bled off. Maybe the pump works off electrical power and so is active with the key in position 2? (Naah..can't be the case, can it?)

Any thoughts or comments gratiously accepted.

Kevin Moak
1991 750iL
Kevin Moak
1991 750iL

     I've noticed much of the mail and the latest "registry issues" discuss
     many HVAC, electrical problems and parts that fixed them from
     PROGRAMA.

     This may be in the FAQ but here goes anyway.....

     POSSIBLE PROBLEM:

     My HVAC in Auto mode may be malfunctioning.  I'm not really sure.

     SUMMARY:

     When the dial is set at the first detent (low) if works well at a very
     low, cold flow.  In the last detent (high) it works but does not blow
     very cold air.

     In the mid/variable position it works most of the time.  However,
     sometimes it will just stop blowing for "a while" (usually when I'm
     stopped and no air is moving).  Note: When the outside temp is 105 F
     and the inside temp starts to exceed it, I NEED the A/C.

     If I manually change the setting to HIGH it works well, but does not
     stay cold for very long.

     QUESTIONS:

     Is this normal behavior for an 88 750iL HVAC system?

     Will the Programa replacement part, that several digester's have
     installed below the radio, fix the climate control/fan speed problem?

     Is it worth having the dealer/Dinan have look?

     Will I have to re-mortgage my house to pay for the fix/replacement?

     Any help is greatly appreciated.

     Thanks,

     Paul Jones
     88 750iL

Paul Jones wrote:
>
> POSSIBLE PROBLEM:
>
> My HVAC in Auto mode may be malfunctioning. I'm not really sure. >
> SUMMARY:
>

>     When the dial is set at the first detent (low) if works well at a very
>     low, cold flow.  In the last detent (high) it works but does not blow
>     very cold air.

>
This could be caused by a fault in one of the flapper controllers or by low gas in the A/C system.
>

>     In the mid/variable position it works most of the time.  However,
>     sometimes it will just stop blowing for "a while" (usually when I'm
>     stopped and no air is moving).  Note: When the outside temp is 105 F
>     and the inside temp starts to exceed it, I NEED the A/C.

>
Now this sounds like the fan control board. The board (some call it the "sword" because that is what it looks like) has a thermal limiter on it and it might be shutting down.
>

>     If I manually change the setting to HIGH it works well, but does not
>     stay cold for very long.

>
Do both driver and passenger vents blow air at about the same temperature when this happens? If so, it is probably not a flapper controller because this would require both the driver and passenger sides to fail at about the same time.
>
> QUESTIONS:
>
> Is this normal behavior for an 88 750iL HVAC system? >
Don't think so.
>

>     Will the Programa replacement part, that several digester's have
>     installed below the radio, fix the climate control/fan speed problem?

>
Possibly.
>
> Is it worth having the dealer/Dinan have look? >
Diagnosis shouldn't cost too much, so that sounds like a good plan. >
> Will I have to re-mortgage my house to pay for the fix/replacement? >
Not for the fan controller. Anything other than a A/C recharge is probably going to be expensive. Take it in a let them tell what it is going to cost.

Let the list know what the shop finds.

Good Luck,

Doug

A '91 850i 6-speed belonging to a friend has developed some strange squeaks from the various flaps and valves in the climate control system. When the system is set on automatic and the brain decides to adjust the air flow to stabilize the temperature, you can hear the flaps squeak as they move.

His dealer has been no help with trying to lubricate them - the car is out of warranty... I would imagine the ducting is a quite a labyrinth and the valves would be difficult to get at. Does anyone have any thoughts?

My suggestion was to drown the squeaks out with one of those new Stebro stainless exhaust systems from John Dimoff (details available from the addresses below, not above - that5 one expires on Friday, July 5.), but he thought he would wait until the factory exhaust expired.

You Wrote:
From: Steve Johnson <SJOHNSON_at_clitho.com> Date: 16 Apr 96 16:00 cst
Subject: 91' 735i A/C Heating Problem

Hi Folks,

My '91 735i has a problem where it will not stop pumping heat out of the side defrosters no matter where the A/C and Heater controls are set. I can have everything off and it will still lightly blow 150 degree air out of these vents and the rear floor vents.

Someone told me this is a computer problem with the heating cooling system, but the dealer just says "never heard of it". I find that to be comfortable, I have to run the A/C in 50 degree weather to offset the high heat output. In the summer, the AC cannot overcome the excess heat good enough to cool the car, and when it is first turned on I get a friendly BLAST of VERY HOT air from the A/C vents.

Any sugguestions for me to pass on to my service guy would be VERY much appreciated!

Steve Johnson
Kansas City, MO

I Reply
"There is a valve located on the drivers side firewall. It has two heater hoses and two solenoids controlling the h20 flow to heater cores. If these coils are not getting any power, the go to full on.. hence full heat. The trouble is probably in the wiring/switches. If you make up a jumper wire you can dump power into the control valve and see if the valve closes. If you make a good setup you could leave it on all summer, and take it off in the winter.

The body computer normally pulses this circuit on and off by making and breaking the ground to this circuit depending on temp setting.

The dealer fixed mine(88e32) In one hour, and charged me60 bucks. He jumped the swithc on my panel and its fixed.

Good luck

I have had various electronic glitches with my 92' 735i that have all the signs of firmware bugs. For example, last night I get a "1 Brake Light" message, but the brake lights are fine, and after the message clears my trip meter goes to zero (000.0). For that matter, my trip meter has gone to zero several times of late for no apparent reason. I have also had the problem where the engine is hard to start and I get the "Check Control" message. I suppose it is possible that I have a hardware problem that is causing these odd behaviors, but it feels more like code problems to me. Has anyone heard of BMW providing firmware upgrades to the computer system on the car? If so,
where can I get it?

Thanks
Dave

> From: Dave Tostenson <davet_at_pioneer.rose.hp.com> > Subject: Firmware Upgrades?
>
> I have had various electronic glitches with my 92' 735i that have all the > signs of firmware bugs. For example, last night I get a "1 Brake Light" > message, but the brake lights are fine, and after the message clears my trip
> meter goes to zero (000.0). For that matter, my trip meter has gone to zero
> several times of late for no apparent reason. I have also had the problem > where the engine is hard to start and I get the "Check Control" message. I
> suppose it is possible that I have a hardware problem that is causing these
> odd behaviors, but it feels more like code problems to me. Has anyone heard
> of BMW providing firmware upgrades to the computer system on the car? If so,
> where can I get it?
>
Dave,

While I don't think these problems are firmware, let me tell you about that anyway. Each car is manufactured at a certain point in time with firmware that is EPA/DOT certified at that moment. I wanted to upgrade my computers (three: main & two engine control) to newer rev software but wasn't able because the certification is only valid for your batch of 750s manufactured during that period. When my computers had to be eventually replaced, the units had to be burned in with my old software in Germany. Took many weeks to get the job done...

C.P. Koch

C.P. Koch
Tel: (716) 856-5245 Fax: (716) 854-1184

From: kimk_at_tpower.com (Kim Kokkonen)
Subject: Re: Firmware Upgrades?

Dave - my '89 750iL has been having very similar problems (trip odometer resetting itself and bogus warnings on the dash display). I have it in an independent shop now to get this and some other things fixed. They have done a
lot of diagnostic work and tried replacing a couple of relays without fixing these particular problems. (They did trace down and fix some other electronic
gremlins with minor parts costs, so I tend to trust their integrity, unlike my
local BMW dealer, who just wanted to replace every expensive control unit in the car.) The independent shop finally concluded that it needs a new "instrument cluster control board" or "SI board", which is a $750 part (the BMW dealer wanted $900 for the same part). It's on order now and I should know
in a week whether the fix works.

I've read in some of the BMW publications that many of these kinds of problems
are caused by broken circuit board connections, bad solder joints in the control board, or even a bad NiCd battery. Unfortunately I tend to make things
worse when I work on complicated machinery <g>, so I'm not going to try to pull the card out myself and mess with it. I think the BMW Enthusiasts Companion from Bentley Publishers has instructions for pulling this card and fixing some standard problems, if you have a knack for this kind of thing.

Dave - just to follow up on my previous message: my mechanic did install a new
instrument cluster motherboard on my '89 750 and my problems with the trip odometer, bogus warnings, etc. have gone away. I inspected the old board and there was nothing obviously wrong with it, but it is a fine-line circuit board
with lots of chips so it would be really hard without diagnostic equipment to
track down the problem.

-Kim

The light bulb in my OBC has been going off and on, it seems like it is ready to go or it is loose. I tried to pop the OBC off but I cant get it loose. Could somebody post the steps in taking out the OBC?

TIA

I recently purchased a '91 735il with about 60,000 miles on it. It ran fine until last week when the poltergeists invaded: No power, wouldn't idle, EML and ASC lights on intermittently. The dealer futzed around for a while clearing the 15 faults displayed by the diagnostic computer and finally installed an air flow meter. That didn't fix it so now they think the EML module needs to be replaced. As this is a $1,000 part, I'm wondering if a) anyone out there has any experience with this sort of nonsense; b) any alternatives to shelling out a grand; c) are there any other problem areas that might cause these symptoms (preferrably a $1.98 part that can be replaced without tools). I'm resigning myself to the $1,000, but I do like to know that there are no alternatives.....

nmacmull_at_hq2.walldata.com

I recently went through a similar problem. I have an '88 750IL with several performance upgrades and ~ 122K miles. About 2 weeks ago, my EML light came on and the 750IL lost significant power. I went to a local BMW dealer and, like yours, cleared several faults. However, the service dept. indicated that I may need a new DK motor ( there are 2 in the 750IL ) and he asked me to monitor the car behavior. As I approached my house ( ~ 25 miles from the dealer ) the EML light came on and power loss was exhibited. The next morning I returned to the dealer and left the car there. Sure enough at 12:00 pm I got a call at work from the dealership indicating that I indeed did need one DK motor ( Part: $800.00 + Labor: $150.00 ). Since then the car has been running fine.

Incidently, the DK motor, according to the dealership, is a motor that control/manages the throttle in the engine. In my 750IL, one of the two dk motors had gone bad which resulted in inappropriate air/fuel mixtures in the engine.

Hope this helps. If indeed this is your problem, I would definitely bite the $1000.00 and let the dealership fix this.

'88 750IL Sanjeev Saxena

This is very common! The reason is that at 30K miles, the mechanic is instructed to pull the oxygen sensor wire from the back of the instrument cluster. If the mechanic isn't careful, it is very easy to pull the identical wire next to it (different color, brown if I remember) off at the same time. Bingo, no tach.

Chris Koch
Tel: (716) 856-5245 Fax: (716) 854-1184

I have a situation with 7 where the mirror will tilt irratically, no matter the
position of the "selector" switch.

This happens more in the wet than in the dry. I'm assuming its a ground connection of some sort, but perhaps someone on the list knows more about this.

Is there a relay or control module that could be causing this?

-Al
1990 735i

Here is the short and sweet of it:

1. Place the ignition on the start position, but do not engage the starter ( all check lights will be on)
2. Fully depress the accelerator and release. Do this cycle five times in a row. The top-to-bottom-to-top-again cycle should take about one second.
3. The check engine light will now begin blinking, beginning with code 1224, which is the start sequence. The check engine light will flash one time and pause for ~1 sec, flash twice and pause for ~1 sec, flash twice and pause for ~1 sec and flash four times and pause for ~1 sec. Then it will flash on for ~2 sec. each flash sequence indicates the code number. Each code is four digits long (i.e. 1224, steady light, 1223, steady light). A second code 2224 indicates the start sequence for the second Motronic computer in 12 cyl engines (like our beloved 750iL). Error codes for the second computer begin with 2, such as 2223, 2134, etc.

HAVE FUN, IT WORKED FOR ME, LET ME HEAR SOME FEEDBACK!!!!!!!!

I will download the codes later for your reading pleasure.

Dear PM,

It is really very easy for any transistor head to solder in new flea lamps. Radio Shack has two for $1.99 plus tax.

All this talk about bulbs has encouraged me to go outside and see if the squirrels have dug up our tulips. Usually they beat the weather - I hope that Buffalo will warm up by mid-May.

Chris Koch

This is the check procedure from the BMW shop manual have.

The first parts are real simple, but the later do have some insight.

Looking at factory repair manual:
The cruise works "from about 22mph to almost maximum road speed". "The system switches off automatically when the actual road speed drops below
the set road speed by approx. 15%."
"When the road speed picks up by 6 to 8 km/h (4 to 5mph) more than the set road speed, the fast seperating clutch opens and the throttle goes into the idle postion. If the road speed goes back to the set value, the clutch will close again."
"Adjust cable with knurled nut until there is play = 1 to 2 mm (0.039 to 0.079")."

"TROUBLESHOOTING CRUISE CONTROL

"Test Requirement:
Battery charged - battery voltage okay. Specified multimeter functions (e.g. M 01) are in reference to the BMW SERVICE TEST. the following multimeter functions are required: 01/06/14. The following test procedures do not include sources of defect, which are outside
of the electronic cruise control system.

"Check fuse no. 12 and contact of fuse. Fuse and contact okay?
no--> Replace fuse. Clean an bend fuse holder. Yes--> Continue

"Check bulbs of stop lamps and their contact. Bulbs and contact okay?
no--> Replace light bulbs. Clean and bend contacts. Yes--> Continue

"Check cable adjustment.
Cable adjustment okay?
no--> Adjust cable. Replace cable, see 65 71 040 in Repair Manual Yes--> Continue

"Check cable and strap of operating motor for damage and easy movement. Cable and strap okay?
no-->Replace cable or operation motor
Yes--> Continue

"Check adjustment of brake and clutch cable pedal switch. Adjustment okay?
No--> Adjust brake and clutch pedal switch. See Group 35 of Repair Manual Yes--> Continue

"Check all plugs (see wiring diagram) and wires for tight fit and damage. Plugs and wires okay?
No--> Repair or replace plugs and wires. Yes--> Continue

"Connect ohmmeter (M 06) between ground and wire (23) on disconnected control
unit plug.
Ohmmeter should display approx. '0' ohm. Resistance value okay?
No--> Correct ground connection according to wiring diagram. Yes--> Continue

"Pull off plug on control unit.
Connect voltmeter (M 01) between ground and wire (1) on disconnected control unit plug.
Turn on ignition.
Voltmeter should display operating voltage* for control unit. Voltage value okay?
No--> Correct power supply according to wiring diagram. Yes--> Continue

"Connect voltmeter (M 01) between ground and wire (2) on disconnected control
unit plug.
Turn on ignition.
Voltmeter should display operating voltage* for control unit. Voltmeter should display approx. 0 volt. Selector lever shitch pressed in 'off' direction - voltmeter should display approx. 0 volt.
Voltage values okay?
No--> Check and repair 'selector lever switch - control unit' plug and wires.
Replace selector lever switch.
Yes--> Continue

"Connect voltmeter (M 01) between ground and wire (4) on disconnected control
unit plug.
Turn on ignition.
Voltmeter should display approx. 0 volt. Selector lever shitch pressed in 'constant' direction - voltmeter should display battery voltage.
Voltage values okay?
No--> Check and repair 'selector lever switch - control unit' plug and wires.
Replace selector lever switch.
Yes--> Continue

"Connect voltmeter (M 01) between ground and wire (5) on disconnected control
unit plug.
Turn on ignition.
Voltmeter should display about 0 volt.
Selector lever shitch pressed in direction 'call'. Voltmeter should display operating voltage*. Voltage values okay?
No--> Check and repair 'selector lever switch - control unit' plug and wires.
Replace selector lever switch.
Yes--> Continue

"Connect voltmeter (M 01) between ground and wire (9) on disconnected control
unit plug.
Turn on ignition.
Voltmeter should display approx. 0 volt. Voltage values okay?
No--> Replace brake pedal switch See Group 35 of Repair Manual. Yes--> Continue

"Connect voltmeter (M 01) between ground and wire (9) on disconnected control
unit plug.
Turn on ignition.
Operate brake pedal.
Voltmeter should display control unit operating voltage*. Voltage value okday?
Yes--> Skip to freq meter question

No-->
>Check stop light switch.
>Pull off both plugs on stop light switch. >Connect ohmmeter (M 06) on stop light switch. >Operate brake pedal.
>Ohmmeter should display approx. 0 ohm. >No-->Replace stop light switch.
>Yes--> Continue

>"Check clutch switch.
>Pull off both plugs of clutch switch.
>Connect ohmmeter (M 06) on clutch switch. >Ohmmeter should display approx. 0 ohm. >Operate clutch pedal.
>Ohmmeter should display 0 ohm.
>Values okay?
>No-->Replace clutch switch.
>Yes--> Check wires, repairing if necessary.

"Connect frequency meter (M 14) on wires 3 and 6 on disconnected control unit
plug.
Lift car.
Start Engine.
Run briefly to speed of about 50 km/h (30mph). Frequency meter should display frequency*." Okay?
No-->Check speed tranmitter for speedometerm see Group 62 of repair manual >No--> Check wires, repairing if necessary. Yes--> Continue

"Connect control unit plug again.
Following tests are made on 7-pin plug for 'control unit - motor'. Connect voltmeter on connection (4) and on connection (3). Turn on ignition.
Voltmeter should display about 8 volts. Voltage value okay?
no --> Replace control unit.
Yes--> Continue

"Connect voltmeter on connection (3) and connection (7). Turn on ignition.
Voltmeter should display voltage.
Voltage value okay?
no --> Replace motor
yes [continue]

"Disconnect 'control unit - motor' 7-pin plug. Connect connection (1, white) on ground. Connection connection (6, green) on B + (12 V). Clutch must be heard to switch.
Clutch switching?
no --> Replace motor
yes [continue]

"Connect ground on connection (2, blue) and B + on connection (5, black) of 7-pin plug on motor.
Motor must be heard to run.
Motor running?
yes --> Replace control unit
no --> Replace motor."

"* See Specifications

Chris Guy - BMW535i86_at_aol.com

My '87 535 had top be towed off the highway this morning after it died while cruising _at_ 65-70mph.

I first felt a sputterring and intermittent power loss and then followed by total power loss. No dash lights actually came on during the power loss until I had pulled off the road.

I was able to restart the engine while sitting at the side of the road but it died again as soon as I put it under load (started to release clutch). I tried to restart again but it failed.

After sitting for 10-15 minutes I was able to restart the car and it idled for about a minute before dying again... this time I had not put it under any load.

Additional history & background:

• -These same symptoms presented themselves yesterday while again driving at highway speed. The engine sputtered, then lost power momentarily but then regained power. Symptoms did not reappear rest of day yesterday or first 3-5 miles of driving this morning.
• -I noticed a burning smell inside the car this morning immediately after pulling the veh8icle off the road. I checked under the hood and could not find any evidence of electrical problems. The burning smell was only evident inside the car.. not under the hood.
• - For the past several weeks I had been feeling that engine had a "lean" surge at light and moderate throttle... below 3500 rpm. At a constant throttle opening it felt as if the engine would get a temporary surge and then diminish. No surge was evident at idle.
• - I replaced plugs, cap/rotor approximately 5K miles ago and the fuel filter I replaced just 2 weeks ago.

Any help with diagnostic tips would be greatlyt appeciated. I certainly seems to be a fuel delivery problem but I'd like to isolate it to the: pump relay, sensor?, tank pump, primary pump.

TIA,

Jonathan

Caught your posting on the Digest. Your symptoms suggest a classic case of needing an oxygen sensor. Surging & hesitation. Surging could also be the Idle control valve under the hood. Checking that requires a minivoltmeter & a Bentley Manual. I'd start with the o2 sensor & go from there. New sensor assembly runs $135-150. We sell a EZ-Fit Tip Kit for $59.95 (New BOSCH). For more info see our Web Page listed below. Idle Control Valve New BOSCH $89. If the car has (miles) replace both & move on w/ your life. Any ? call or E-Mail back we'll be happy to help you. Rodd Sidney

Rodd Sidney                BMW Dealer Marketing Web Page
bmwrodd_at_dzn.com        http://www.dzn.com/global/bmw.htm

Dear Tom,

Personally, I would start working on your (new) 733i in other areas before getting into increased performance. I'm willing to bet that a good flush of all fluids (see synthetic comments above) including engine, transmission, axle, brakes, steering, A/C and cooling is in order. I would first drain and replace the lubricants with standard stuff, run it for two weeks and then replace once again with the synthetics. Then, since the synthetics will find every leak, go through everything and replace the necessary gaskets and seals. Change all filters (gas, oil and air).

Then, go through the engine systems. Cap, rotor, wires, plugs. Mass flow and idle controls - do they work freely, are they clean, are the electrical contacts clean and lubricated (silicone spray)?

How about brake pads, calipers, rotors, tires?

Did you replace all of those little missing or broken plastic pieces inside and out? Do all systems work? Windows, locks, seats and sunroof all probably at least need lubrication. I take all of mine apart, clean and relube.

How is the body work and trim? Seats, doors, headliner, rugs?

OK, now you have a straight car, a basis to which you can now play and add as many questionable "improvements" as you wish.

Good luck, Chris Koch