Section 14: E24 & E28 ('76-'89 6-series and '82-'88 5-series)

14.1: Overview

14.1.1: Oversteer
14.2: Body
14.3: Engine

         14.3.1:   Adjusting valves
         14.3.2:   Loose Big 6 Oil Spray Bar Bolts
         14.3.3:   Transfer pump
         14.3.4:   O2 sensor light
         14.3.5:   Idle problems
    14.4: Suspension & Steering
         14.4.1:   E24 Steering Bolt
         14.4.2:   Vibration
    14.5: Brakes
         14.5.1:   Vibration
         14.5.2:   Brake Bomb (booster)
         14.5.3:   Upgrades
    14.6: HVAC
         14.6.1:   Heater Control Valve Problems
         14.6.2:   Fan Blower
         14.6.3:   Heater Core Service
    14.7: Electrical
         14.7.1:   Wiring fog lights to work with low beams
    14.8: Misc
         14.8.1:   Replacing a clutch
         14.8.2:   Instrument Cluster removal
         14.8.3:   TRX tires
    14.9: Performance
         14.9.1:   Epxerience with a E28 Dinan chip

>I just wanted to ask whether or not it's true that my '85 528e will be rather >dangerous to drive in the snow. I just got her and have not experienced >winter, which is normally quite extreme here in Providence RI. Should I get >snow tires? Chains (?!)-rather not.
>
>I have already skidded on wet pavement and it was quite frightening. >Fortunately, nothing was damaged and no one injured. Except my ego...

The E28 chassis is known for being a bit "tail happy" at times. This is not so much a flaw, but a characteristic. This behavior can be very useful or very dangerous, depending on the driver's knowledge of car control. The car can get tail out under two circumstances:

1. Too much throttle in a turn -- typically encountered when accelerating through an intersection. The rear tires loose traction due to wheel spin, since the car is already rotating in the turn, the rear end swings around.
2. Letting off the throttle or applying the brakes in a turn. Slowing down transfers weight (and traction) from the rear to the front. With a semi-trailing arm rear suspension, the loss of traction is exacerbated by the fact that the camber goes from negative to positive. This can lower the traction in the rear to the point that it starts to slide. Again, since the car is rotating through the corner, the rear end swings out.
3. If situation number one happens, and the driver's reaction puts the car into situation number two, the car will spin really well.

Here's some advice:

1. Go to some kind of car control school, preferably one which has wet skip pad work. Get very comfortable with the correct-pause-recovery process of controlling a tail-out skid. (It's waaaaaay fun.) Find a nice, big, wet, empty parking lot to practice after you have learned the technique.
2. If you expect to encounter ice, throw a 100 pound bag of sand in the trunk. I believe this advice can be found somewhere in the owners manual.
3. Snow tires are probably a good idea. Being from sunny California, I can't help much here.

Rear drive cars give higher performance and better control, but if you don't know what to do with the extra control, you may find yourself pointed in the wrong direction.

cheers,

• -MRM

Peter LaPine: plapine_at_star.enet.dec.com Don Eilenberger: dje_at_bellcore.com

>I plan to attempt to do a valve adjustment on my car this weekend (my >first time!). I have a feeling that the job is really easy, but that >having someone experienced offering tips like pointing to the valves >:-) would be handy. I have the Bentley book, which is reasonably >clear, but I was wondering if one of you old pros could recall some of >the "lightbulbs" that went on the first time you did it yourself.

>Before starting, looking through the guide, here are some questions >that arise:

>1) Crankshaft rotation is done on the "vibration damper bolt". Where >is that? Figure 4-25 of Bentley shows the vibration damper: is the >bolt where the pictured wrench is securing it? Or is it somewhere >else?

I don't know about the 325 engine.. but I find it MUCH easier to rotate the engine using the nut on the alternator. I can fit a large socket (I think 19mm) and a 1/2" ratchet on this nut.. no way I could get it on the crank "vibration-damper-bolt" - which is the bolt at the end of the crankshaft which holds the damper on. (Dead center at the bottom of the engine, facing the radiator). You may have to use one hand to put some additional tension on the alternator belt when turning it.. but it sure beats trying to get a wrench all the way down to the crankshaft. Always turn clockwise...(or the nut will loosen up).

Second opinion:
On the 535i, I remove the fan clutch assembly by loosening the large nut immediately behind the fan clutch. NOTE: it is reverse threaded!!! So turn it CLOCKWISE (instead of counterclockwise) to loosen it. I use channel locks to remove it. Then I use a large screwdriver blade against the heads of the bolts which fasten the fan pulley to the water pump to turn the engine over to potition the cam lobes for appropriate valve adjustment

o

• o
• o

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Place the screwdriver blade against the top of bolt head in clock position 1 and against the bottom of the bolt head in clock position 7. With the handle sticking out past position 1, push down and the engine will turn over. Besure to keep pressure toward the engine. Be careful not to slip and punch a hole in your radiator...

>2) The stiff wire tool: can I use a coat hanger?

IF you can find one the right size.. I usually use a allen wrench (don't remember what size..) it is very stiff, and has the needed "L" shaped hook in it. Rummage through your tools.. you'll find something that works. I sorta think a coat hanger wire might not be strong enough.

>3) Do I really need to take my plugs out to do the valves? I'm >planning on replacing them anywaythis weekend as part of the >Inspection II; does this really help.

YES! Unless you're godzilla! IF you don't take out the plugs, you'll be attempting to turn the engine over against cylinder compression. Removing the plugs makes this a WHOLE LOT EASIER! (And if you're replacing the plugs.. why NOT?)

>4) Figure 4-27 shows the feeler gauge being inserted. Where exactly >is it going - between the rocker eccentric and the top of the valve >stem?

Exactly. And - to really adjust it correctly, I make certain that the cam lobe is facing exactly away from the rocker mating surface when I make the adjustment. This does require more turns of the crankshaft-- but makes for a better job.

Just make all the valves have the same tension- that's important because you don't want the relative clearances to change when the engine heats up.

I typically:

1. loosen the nut
2. place the feeler gauge between the concentric disk

   and the valve stem

3. press the concentric disk towards the valve stem and

   at the same time tighten the nut

4. recheck the clearance (should be a SLIGHT drag -

   you shouldn't have to force the gauge in, nor should it slide in with no resistance - just some...

   • this 'feel' is what comes with experience...) and repeat, if necessary, until it's right.

           this is where you can spend some time.  I usually
           have 2 or 3 that require diddling back and forth
           a few times until they're right.  Remember, since
           you're taking the time to do it, you may as well
           get it right...

>5) What exactly is being accomplished by adjusting the valve >clearances - if the valve is closed, and there's clearance between the >rocker and the stem, why should it matter if the tolerances are off a >bit? What would the performance implications be?

You're setting the valves so they open the correct amount, and at the correct time in relation to the ignition/exhaust cycles. The tolerances are surprisingly small - minor changes do lead to rough idle. As far as performance.. if they're way to tight, you stand a good chance of burning the valves (they aren't closed enough to cool), and ruining a camshaft (constant contact lobe/lifter - can lead to oil starvation and galling of the cam). If they're too loose, about all you'll have it lots of noise and a loss of power (not open long enough to let all the mixture in, or all the exhaust out). I guess it is possible that the extra impact on the cam/rocker could also cause some damage if they're too loose.. but I've never seen this personally.

>6) Any tips on different clearances I might want? '86 325

Set the plug gaps to at least the BMW specs... a bit over won't hurt (0.002-4) and on 535's is known to improve the idle. (NOTE, this offers no advantage on the M20 (2.5/2.7 liter) engines.)

>Any other useful tips

Several to be exact:

1. Do it with the engine stone cold! - Meaning do it after the engine has sat not running overnight! I have found from experience that you cannot adjust BMW valves on an engine that is even a little warm.. the aluminum head changes dimensions so much with temperature that by the time you've gone from one end of the valve train to the other, the settings you set at the beginning are not anything like what you set for the last one.
2. Do it at least twice.. don't ask me why, but BMW valves always seem to require this. The first time through you get them close.. the second time you'll get them dead on. I always use three feeler guages. The 1st is 0.001" smaller than spec, the 2nd is the specified spec, the 3rd is 0.001 larger than spec. When you're done #1 should go through with NO drag. #2 should go through with a bit of drag. #3 should be very hard to push through.
3. Get angled feeler gauges (Sears used to have them) that are made for adjusting valves. The layout of the BMW valve train is such that the slight (30 deg. or so) angle on the end of the feelers makes the job MUCH easier.
4. Don't do it when you're likely to be in a rush. If you know you have to go somewhere in 3 hours, wait until the next day.. the first time you do this it will take a while, and the job will go better if there isn't an S.O. popping out every so often asking "are you almost done?? We have to leave soon..."
5. Don't drink and adjust valves (a lesson I learned when I owned a Jag XKE - which required REMOVING the twin cams to adjust the valves).
6. Buy a new valve cover gasket. Old ones USUALLY work - but when they don't it's a pain to have to remove everything to get at it again!
7. Change the oil afterwards.. just in case any crap fell in while the engine is open.
8. While buying the valve cover gasket.. get a few extras of the lock nut and little bolt that go though the eccentric adjuster. I've never broken one.. but they are very small and look easy to bust (which would ruin your day if you don't have a spare). I use the 10MM box wrench from my trunk tool kit on these - it's about 6" long and seems to provide just enough leverage to keep me from overtightening these. I don't know what the torque spec is on them, but it would be difficult to get a wrench in there anyway while attempting to keep the eccentric from moving.
9. Doing the actual adjustment.. I usually loosen the nut enough so the eccentric moves easily, then insert the feeler and move the eccentric until I can feel it contact the feeler/valve stem. I then tighten the nut just a bit, and try moving the feeler. You'll find that tightening the nut tends to close up the adjustment, so you will have to now move the eccentric with the slightly tightened nut. When you think you have it right - use feelers 1, 2 & 3 to check. If it feels OK - then tighten the nut a bit more, and check with the feelers. After you do the first few, this will become easier. Make sure you check after each tightening of the nut with the feelers.. the clearance does tend to change *just* a bit. Don't overtighten the nut/bolt - I use 3 fingers on the end of the 6" wrench.. haven't had one break or come loose yet!
10. Replacing the plugs.. hopefully you're using the silver ones that BMW specs.. others just don't seem to work as well. You should not need anti-seeze (the plugs are nickel plated).. and you should TORQUE them to the correct specs. Overtighten and you stand a chance of stripping the threads in the head. Undertighten and they'll back out while driving.. a good torque wrench (Sears ones are OK) is a cheap long-term investment that any driveway mechanic SHOULD have.

(Editor's note:
The hollow bolts that hold and take oil to the bar which provides oil to the cam lobes on the big 6 engines are prone to loosen up, with potentially serious consequences!)

Actually - there are two of them to look for (and it turns out BMW-Alfred of the 528i/533i's has had them come loose also, plus my mechanic friend ALSO said "they all do that...").

So.. whilst the valve cover is off for your periodic valve adjustments - check the TWO bolts (13mm heads) that go THROUGH the oil spray bar line that runs forwards/back on top of the engine (over the camshaft). They'll be pretty obvious.

I tightened to something like 10-11 ft/lbs - more than this I wouldn't go - these are hollow bolts - and possibly aluminum - so there is a GOOD chance of shearing off the heads if you overtighten them. At about where I stopped, I could just see a bit of deformation of the actual oil spray line..

There has been a thread here - on the number of times people have found these bolts loose - they should be checked whenever the valves are adjusted. The last time I adjusted BOHICA's valves - I installed the new style bolts. The article claims that once they are installed and torqued properly, they should not be removed, loosened or retorqued.

To identify if you need the new bolts (1) if they loosen up by themselves - you do (2) if your bolts do NOT have a ring machined in the top of the bolt - you do. I would also suggest replacing the crush washer that goes under the bolt at the same time (something the article doesn't mention).

The part number is 11-41-1-738-621, and suggested tightening torque is 11-13Nm (8.1-9.6 Ft/lb).

FWIW!

Don Eilenberger (dje_at_mail.bellcore.com)

For more info (checking the xfer pump,etc), see the E30 chapter (15)

You will need:

1 screw type 1/2" hose clamp
1 screw type 3/4" hose clamp
(These are to replace the crimpons, which you just wheedle out carefully with needle-nose pliers)

That's it! Of course, to be really safe, you should buy the gasket that seals the transfer pump to the gas tank. The sending unit is in the center of the transfer pump mechanism. The sending unit is non-servicable. It is a silver canister, about a foot long, with electrical connections on top and a small nut with ground strap on the bottom. There are a couple of small (2 to 3mm) holes down the side of the pump. You'll get gasoline all over yourself if you aren't careful when you remove it. The new sending unit should have the o-ring, but check to make sure it does. I tried to take my sending unit apart, but all I did was screw it up worse (silly me - I thought it was the transfer pump at first!)

Steps to get the unit out:

1. get access to it first (remove trim piece in back of trunk)
2. lift up floor of trunk
3. Unscrew the cover - it's a disk about 8" in diameter
4. You need a 7mm socket wrench. Pretty small, so make sure you have one. It's the same size that the distributor cap uses on an '83 528e.
5. Take the hoses off FIRST - makes life a lot easier
6. There are two nuts for the sending unit - you have to take the sending unit out to get the transfer pump out, unless you like to spend about 5 minutes trying to angle the whole assembly out
7. Unscrew the 8 or 9 bolts for the transfer pump slowly, going round and round (I did that because I didn't have a new gasket and didn't want to mess it up)

Truly, it is *very* easy to do.

>The oxygen sensor light went on in my 1988 528e. I have replaced the >sensor with the same exact model/part number as the one that was in it >before (A Bosch; 4 wires attached to the sensor) at the cost of 150 bucks!

>The light still stays on.

save your $225!!

there's supposedly a 100mA fuse in the back of the instrument panel behind the speedo that needs to be replaced in order to turn off the light.

Above the accelerator pedal, there's a plastic gizmo box that is a little odometer. It basically blows the fuse after every 30Kmi or so. You need to reset that by pushing the recessed button with a screwdriver or pencil, so it can blow the new fuse you will put in 30Kmi later...brilliant huh?

Now, don't ask me why the O2 light is run off of a not-readily accessable fuse that needs to be replaced every 30K mi. That's outright stupid for those who can remember to replace the O2 sensors ourselves. (It's more reason to charge more labor and therefore justify the charge to replace the O2 sensor at the shop)

Anyways, I haven't bothered with replacing my fuse just yet. I'll do it the next time I yank the instrument cluster out and take it apart.

In the meantime, I've just removed the O2 light from the panel above and moved it to one of the spare locations. My O2 'light' stays off :-)

Evan W Evans (de'juvu).. asks about 535 idles problems. Something I just happen to know a bit about (a 2 year battle with BOHICA).

>Subject: 535is Driveability Problems
>
>I just installed a new Bosch idle control valve in my '88 535is (55K) hoping >to cure an annoying idle/driveability problem (it didn't help so I cleaned the >old one up and reinstalled it, car runs the same maybe slightly better). >Symptoms: Idle tends to vascilate between 650-750rpm and the driver can >perceive a slight shaking of the car due to the idle while at a stop. The car >stumbles slightly when cold and I think I'm hearing a slight backfire before >it's warmed up. I've also detected that it doesn't pull smoothly once I'm >around approx. 2700rpm. It feels like the car pulls....hits 2700rpm and >begins to lose power then pulls through 3000rpm.....and loses a little torque >andthen begings pulling thru the rev range again. Granted this is such a >slight loss in power it's probably imperceptable to most, but I want to fix it >unless I find out that "they all do that." I've checked for vacumn leaks and >found none. I've installed new Bosch Platinum plugs and increased the gap as >advised. What else am I missing? Also, any remedies for the "hard to shift into >second gear when it's cold problem"? Any thoughts on installing a K&N air >filter or other mods i.e.,short shifter kit, chip, etc.?

Even, I won't go into the other item's you address, but THEY ALL DO THAT, more or less. Things to do:

1. Throw out the Bosch Platinum plugs - they're basically not compatible with this car. Spend about $4/each for the Silver ones that are ESPECIALLY made for just this engine (check a BOSCH cross-reference book - guess what? The only engine using these plugs is the big 6!).
2. Set them to 0.032" minimum gap. Even to 0.035-38" won't hurt, the ignition system can easily handle it.
3. Install and TORQUE them in with no anti-seeze. 20 fl/lbs is about right.
4. Adjust valves to minimum of +0.002 over spec. +0.004 isn't even noisy and will help even more.
5. Run mega-dose of techron full strength stuff (not the watered down k-mart stuff) [mega-dose = 2 16oz can's in the last 1/4 tank. Run until almost empty. Fill up. Change oil!!).
6. Run the piss out of it. It will like it.

Problems with the '86-88 big six engine idle is related to exceeding (vastly) the EPA emmisions standards. The things run VERY lean at idle (CO is almost unmeasureable at the tailpipe). None of them idle great - but the above can make it tolerable - and not embarrassing at a stop light (car rocking and rolling). The biggest change is made by opening up the valve adjustment, followed by the correct plugs and a wide gap. You'll notice as these open up with normal wear, the car runs better and better - I'm often disappointed after I tune BOHICA up, 'cause it runs WORSE - and end up resetting the new plugs to the gap the ones that came out were at - and doing the valves again. I'm currently running the valves at 0.014 +.001 - .000 - this seems to work well, and with BOHICA gonna reach 100,000 miles TOMORROW - the cam and lifters look JUST LIKE NEW - the car uses no oil, and the compression is excellent, and very even. It won't hurt the engine to run these wider - and will greatly improve the idle.

The reason - it helps the crappy idle these engines are afflicted with due to BMW's attempts to meet emmission regs from around 1985-88 (they actually FAR exceeded them.. there is NO measureable CO at my tailpipe - have to go back to the exhaust manifold to see a reading).

If the car IS tuned to specs - it idles very poorly and tends to intermittently stall. Not all of this may be due to the valve clearance and plug gap - but using the wider settings sure helps.

Don Eilenberger says:
What do I set the plug gap to on my '87 535i? I also set the plug gaps oversize - same reason again - in this case, spec is 0.028" - I typically use 0.032"

If the car IS tuned to specs - it idles very poorly and tends to intermittently stall. Not all of this may be due to the valve clearance and plug gap - but using the wider settings sure helps.

The following is copied from the Sunbelt Chapter BMWCCA July Newsletter, which quotes John Watts of the Buckeye Chapter as follows:

"Owners of the following BMWs take notice of a potential problem: all E24 bodies (6 series), all E28 bodies (5 series), early E32 bodies (new 7 series, 1988 & 1989 models), and early E34 bodies (new 5 series, 1989 model). There is evidence of a design flaw in a bolt that holds the steering box in place. Out of three vehicles we checked we discovered one catastrophic failure, one significant deformation, and only one appearing normal. What I am saying is this: I believe a questionable bolt may be holding most of your steering boxes in place. The old bolt part number is 32 13 1 123 865. The new bolt part number is 32 12 1 136 051 and retails for about $12.00."

I'm just passing this along for what its worth....I'm a lawyer, not a mechanic...but it seemed of a least some possible passing (!) significance.

I think the one thing that becomes obvious from the mail on E28 front ends is that vibrations (1) are fairly common (2) may not be caused by one single item.. but may be the result of marginal conditions of several components.

Here on the list over the past year - I have heard the following to cure front end vibrations:

1. Thrust bushings
2. Tie-rods, center rod, etc..
3. Misc. bushings
4. Replace rotors
5. Upper strut bearings
6. Wheel balance
7. Tire squirm
8. etc..

My feeling is, that as ALL these components age - they work together to ALLOW the vibrations. Good tight bushings may help to damp possible vibrations that would be caused by very slightly warped rotors. Absolutely perfect rotors would not try to induce vibrations that could be amplified by worn bushings. etc.. etc..

It appears from following the postings for the past year - that the same symptoms are often cured by different fixes.

As was mentioned, the E28 front end is very simple and lightweight, and probably is prone to component induced vibrations - and ALL the components must be in good condition for it to work like BMW intended.

(NOTE: Also see the section on suspension and steering Vibration (14.4.2))

After much delay, I have finally created the E28 Brakes FAQ. I believe it to be the most accurate information, to date, on this issue. If you find anything in this FAQ that is incorrect or misleading, I would appreciate it if you would contact me so that I can update the FAQ. I'm creating a WWW page for myself on Mordor, and I will include this with all my E28 info there (be patient).

My knowledge of the E28 stems from about 7 years of ownership of one 1983 E28 that, at the time of this FAQ, has almost 250k miles on the clock (and half a year's ownership of an '87 E28). I am a do-it-yourselfer, and my experience is from the following: working on these cars, getting advice from a particularly outstanding CCA Tips Rep who has serviced hundreds of E28s, and from helping friends that have purchased the same BMW model (E28) and have experienced similar problems with their cars.

If you have corrections, updates, or any additional information that you feel can improve this FAQ, please send mail to bernstein_at_mordor.com.

1. Why is the FAQ needed?

It seems that the E28, the 82-88 5-series, while a popular car amongst BMW people, has a reputation for developing a shimmy upon braking. This shimmy becomes more noticeable over time and mileage. There are many proposed solutions, but no one except BMW AG has spent the research dollars and time to figure out the best solution, and IMHO, they have found it. There has been some conflicting information on this list and amongst some Roundel aftermarket suppliers about the best solution. The intent of this FAQ is to clear up some of these questions.

2. In a nutshell, why does the front end shimmy upon braking?

This is a two-part answer:

(1) This car's suspension was intentionally designed to be responsive and nimble, unlike many big American sedans which allow heavy weight to rest on the front wheels. As a light suspension, it is more prone to transmitting vibrations through the steering wheel. In the E28 (and to some extent the E30 and E36), these vibrations are caused by deteriorating components in the suspension. As these various components wear, the evidence of their wear becomes apparent through vibrations in the steering wheel most noticeably upon braking, and particularly between 50-65 mph (80-105kph).

(2) The other half of the problem rests with the material used in the brake pads and how it interacts with the rotors, and the combination thereof. In the mid-80's, asbestos was outlawed in the USA. After the E28 had already been *designed* and produced, BMW had to search for a semi-metallic pad for replacement parts (scheduled maintenance), because they couldn't sell the asbestos pads once the asbestos law went into effect. The asbestos pads were originally selected because they were able to generate acceptable levels of heat, while it was much more difficult to reach similar specifications with semi-metallic pads. In time, the additional heat generated caused the rotors to warp. During this period, BMW issued many "updates". They used a number of rotor and pad manufacturers, including Textar and Jurid. They did this until they felt they got the proper pad-rotor combination. It was fairly common for dealerships to replace set after set of warped rotors and ruined pads in some customers' cars (dealers can fish for an answer, too). The rotors were often replaced free under the 12-month parts warranty.

3. What parts should be replaced?

If you experience the symptoms mentioned above, your rotors are most probably warped. If you get the shakes at different highway speeds even prior to braking, you definitely have one or more worn suspension components. Whether or not your need to replace suspension parts is a question based on the car's history, age, and mileage. You should not blindly replace the brake components without examining the rest of the suspension. It is common to need additional suspension work in addition to the brakes, particularly on cars with over 100k miles.

Replace all four rotors and pads with stock pads. From a dealer. They're inexpensive. So do all four. ALL FOUR. The labor is so bloody easy that you won't be sorry. Besides, after you do it, and you've insured the rest of the suspension is working, you'll be really happy. REALLY. The most recent service bulletin on this problem (which I have read but do not currently have a copy) recommends replacing front and rear rotors as well as pads.

Brake Replacement Parts list:
Front pads (1 set - usually Jurid 506EE) Rear pads (set)
Factory balanced rotors x 4
Front left brake sensor
Rear right brake sensor
Hex key screws x 4 (provide month/year of your E28 mfg.) 1-2 quarts brake fluid (per mfg. spec.)

As I said, the brake job is quite easy, so I don't see a reason to go into excruciating detail about the procedure for replacing brakes. Bentley, as well as the BMW shop manual, are very clear.

4. Why can't I simply turn the rotors?

Warped rotors cannot be turned. The excessive heat that has caused the rotors to warp changes the composition of the metal so that they will not turn properly, and the problem returns virtually immediately. New rotors from a BMW dealer, with a BMW CCA discount, are so inexpensive that it is economically foolish to turn old ones.

5. I'm trying to get the old rotors off, and I'm afraid of stripping the hex key that holds them on. What should I do?

Don't strip the hex key! Use a fine dentist-type tool to clean out the vertices of the hex key, so that a hex socket can be completely inserted into the screw. Give it a shot of Wurth Penetrating fluid if you've got it. Then (I do this before I remove ANYTHING else), with someone pressing the brakes (or handbrake, if rear), apply a firm torque to the screw. These screws shouldn't be too tight, although dirt and corrosion can make it more difficult. If you strip it, get the easy-outs. I have, twice, successfully removed these screws with easy-outs. It requires patience. Otherwise, drill out the head of the screw and remove the rotor. If all else fails, a sledgehammer (seriously) can be used. One or two whacks to the backside of the rotor (be careful not to hit anything else) will, in fact, do it. Remember, it is only a set screw. The wheel bolts firmly attach the rotor to the hub. Also, on the rear wheels, you must loosen the emergency brake so that the shoes back away from the inside walls of the rotor. The adjusting nuts are accessible through the lug holes in the hub. Then you can remove the rear rotors.

6. Should I flush the brakes?

You should be flushing the brakes once per year ANYWAY. Just do it.

7. Any other nebula to consider, Mr. Enginerd?

Yes, I'm glad you asked. Make sure you torque the wheels to 85 ft-lbs. No more, no less. Believe it or not, this torque spec. insures the proper heat dissipation between the brakes and the wheels.

8. I replaced the rotors and pads with the OEM stuff you suggested. It's only 5k later, and they're warped again. Why??

This is a sign that you didn't find the root cause of the problem. Assuming that they warped in less than 1 year and you got them from a dealer, the rotors are under warranty. You can replace them for free. But you have to examine the other components in the suspension, one by one. Clearly, one must examine each bushing, each tie-rod assembly, and the shocks. Bushings should be checked for hairline cracks; specifically look at the lower control arm bushings and thrust arm bushings. Tie-rod assemblies, track rod, and idler arm should be checked for play, and can be checked by hand. Ball joints (in lower control arm or thrust arm) can be checked by the bar-under-the-wheel test, usually, and should also be checked for visible signs of boot deterioration. Shock diagnosis is difficult, since the "bounce-test" is useless. Often, the type of driving and mileage must be considered, as well as how tires wear, how well the car tracks at high speed, and how much the car leans on cornering. My first E28 lasted with shocks until 150k, my newer one seems to need them after only 80k. Finally, a four-wheel alignment should be performed so that the rear wheel alignment can be measured (there are no adjustments here) and the front wheel alignment can be measured and adjusted. In my older E28, the front strut bearings were the culprit, in addition to the shocks. This made sense, since worn-out strut bearings are not able to properly hold the strut in place upon braking, and the result was a couple of BADLY shaking strut assemblies.

One other thing - don't forget that your wheels and tires are also suspension components, and MAJOR ones. Admittedly, I have only used the stock 14" rims. Rims must not be dented or out-of-round. The same is true for tires. I have seen worn tires make a car feel like it was on its last leg. Save the worn tires for the driving schools. You may need to purchase new tires, but that's the subject of another FAQ. 8^) Whatever you do, don't be a cheapskate when considering tires. (as an aside, for a performance touring tire, I just got the MXV4-Energy tires, and love them)

9. Why buy stock?

I consider this to be fact; others say it's subjective, so standard disclaimers apply. First, with the CCA discount, the price can't be beat. If anyone finds a comparable set of pads/rotors that beats the factory prices, I'd like to hear about it (local ADAP parts need not apply). Second, all parts (excepts bulbs and brake pads) come with a 12-month, *unlimited* mileage warranty. As long as you have a valid receipt from a dealer, they will allow you to replace warped rotors - for those do-it-yourselfers, the only cost is your time to do the labor. I would check with the dealer, at the time of purchase, what procedure they use to replace rotors under warranty. I have dealt with Foreign Motors West (MA) and Hendrick Imports (NC), and they both are completely reasonable. Some dealers will replace them for you even if you didn't buy them there, but this is rare, so don't count on it. One year I went through 4 sets of rotors until I isolated the worn suspension part that was causing the problem (see previous question). As far as I know, I have not been able to locate the Jurid brand pads from anyone other than the dealer. Also, see the next question for a discussion of stock vs. aftermarket rotors.

10. C'mon, what's the difference between the stock rotors and the same rotors from an aftermarket?

Well, aside from the warranty, which is REALLY important to me, the stock rotors are spin-balanced at BMW after the OEM manufacturer (Brembo, Ate, Balo, etc.) ships them to BMW. Some manufacturers claim to spin balance their rotors, but they may use less reliable clip-on or glue-on weights, whereas BMW shaves metal off the rotor to achieve the proper balance. My experience is that from a reputable BMW dealer with an aggressive parts department, you can buy rotors CHEAPER from the factory. The aftermarket dealers that advertise in Roundel have been, in EVERY case, MORE expensive (to my surprise as well), and there is rarely a warranty with their products.

11. OK, now I'm replacing suspension parts. Do polyurethane bushings help?

Not really, unless you are planning to modify the springs, struts, and sway bars. Some people have claimed to use the 750iL bushings successfully, but my feeling is that the car, in its stock form, wasn't designed to run with these, and these stiffer bushings will put more stresses on the rest of the suspension, which were not designed to work with them.

Needless to say, any new bushings WILL help, if your existing ones are worn. The stock bushings are very cheap - the labor is difficult, unless you can remove the ball joint without damaging it, and have a workbench to carefully press out the old bushings and press in the new.

12. OK, I'm using the stock pads and I'm happy. But the stock pads generate a lot of brake dust. Can I use dust shields?

General consensus has been that dust shields are the WORST thing you can do for the health of your suspension. While they do appear to keep the dust off of the wheels, some people have claimed that the heat from braking isn't dissipated properly, and some have empirical data of amazingly fast rotor warpage with their use. A good wheel cleaner is the best solution. I happen to prefer P21S, due to its overall excellent design and environmental-friendliness (it won't kill your cat, it won't ruin your glasses, it won't destroy your brakes). Admittedly, it requires a bit of elbow-grease. But, like Zymol Wax, the results speak for themselves. There has been some speculation about the negative side effects of Armor All's QuickSilver wheel cleaner, but I don't know much about that, except to say that anything corrosive should not be sprayed near any brake components. Period.

14. Speaking of driving habits, can my driving habits cause my brakes to warp?

This is a tough question, because I have some firm opinions here, which all may not agree with. I don't believe in automatic transmissions, because I believe they relinquish much car control to mechanisms that don't have eyes. I feel that with automatics, one must use the brakes much more often since they have less control over the drivetrain. Some people claim that braking with the engine (ie. downshifting) is wrong because brakes are cheaper to replace than a clutch. Well, I got 220k out of my first clutch, and I downshift ALL the time. I'd much rather replace a clutch than play detective with my front suspension. Determining worn suspension parts can be an expensive, frustrating, iterative process.

I guess my real point is that you shouldn't ride the brakes. You should be aware of your driving so that you don't use the brakes until you need to. That may sound simplistic, but if you think about it, and practice it while you drive, you can drive smoothly and preserve your brakes for when you actually need them. Short, firm braking, combined with downshifting, allows far more cooling than riding the brakes for a hundred meters before a stoplight, tollbooth, etc. Your brakes need the time/air to cool. I also don't sit with my foot firmly on the floor at a stoplight, pressing the pads against hot rotors, but this probably isn't an option on an automatic.

15. Can I do driving schools with an E28, or will it warp my brakes?

The answer to this is completely subjective. 8^) My answer would be yes, but to be fair, the stresses on your car during a school are quite high, so you shouldn't complain when things break. As Richard W. says, schools do wonders at "exposing weaknesses" in your car. You can surely commence rotor warpage during a day of "spirited" driving at a school.

16. Are BMWs the only cars that warp rotors?

No. In fact, due to non-asbestos pads being mandated by the government, all cars now use them. One reason that this wasn't as much of a problem with American cars is that they would die long before the rotors warped. On my first E28, they warped after 130k miles. Another reason is that these other cars are designed to provide very soft rides, which usually means very heavy front suspensions, which masked out many vibrations until the vibrations were quite serious. Now, with CabForward designs and more nimble suspensions, I commonly hear about those new Chryslers warping rotors in only 25k miles of driving!

17. Steve, are you this anal retentive with all your automotive repairs?

Yup. 8^)

Just a couple of points to add to your E28 Brake FAQ:

1. In my E28 M5 the factory replaced the front bushings with 750 hydraulic bushings. With the larger wheels and tires which are stock on the M5 (225/50/16ZR tires), this is the only thing which prevented the shimmy from recurring every 8k miles (on a new car, with nothing worn).
2. There is available a spun stainless steel hub cover, which redirects air flow, and GREATLY reduces the incidence of rotor warpage. These can be obtained from Carl Nelson at CNPR 1-800-466-8184.
3. For track use, if you wish to engage in spirited driving, and do not want warped rotors, Cool Carbon Pads are a MUST, IMNSHO. They are the only way I have avoided the problem. At a BMWACA drivers school at Laguna Seca, the Instructor asked me why my rotors weren't warped, as all the other E28 M5's he had been that day were. For the answer, see above.

Keith
o==()()==oo
'88M5, '72 Tii Touring

>From: JonLindsay_at_aol.com
>
>One further question on the "bomb", does anyone know just how it works? It >appears to be just about the last thing in the car ("84 633) to go bad: heavy >solid piece of metal with no moving parts. I now own a replacement unit at >he suggestion of a local mechanic and am wondering what are the tricks to >installation (and just possibly why I spent the $75). >

Jon,

...is a pressure accumulator, the hydraulic equivalent of the water storage tank used in homes that draw well water. It stores pressurized hydraulic fluid for power brake assist with no engine power, as well as instantaneous response. This latter point provides a clue for failure diagnosis.

It is constructed to withstand > 25x atmospheric pressure, but internally it contains a rubber bladder which can rupture. The sealed side of the bladder is precharged to a high pressure (not sure how high), typically with dry N2.

Recall Physics 101: fluids are nearly incompressible, but gasses are readily compressed. As hydraulic pump output pressure increases above the precharge pressure, the bladder deflects, further compressing the precharge and accumulating hydraulic fluid. This fluid volume will remain at nearly a constant pressure as it is withdrawn for braking even if the pump is not operating.

If the bladder fails, the system becomes totally reliant on the pump for pressure, as there is no longer any compressible volume in the hydraulic system. This can result in hard initial brake pedal feel, an instantaneous illumination of the red dash "brake" light (triggered by a sudden loss of hydraulic pressure), then a softening of the brake pedal as pressure from the hydraulic pump builds again.

Replacement is not particularly tricky, as the unit is sealed. However, make sure to keep all ports/hose connections scrupulously clean, tight and leak-free.

The above info comes from some use/design of industrial hydraulic systems, but, particularly, from personal experience after nearly rear-ending someone in city traffic in our '79 733 with defective accumulator!

• Don't ignore the telltale signs, this is a safety issue. Power assist for emergency manuevers will be delayed, reducing stopping margin! ***

Hope this helps!

• --Paul Reitz BMW CCA #1167 325 iX, among others...

I have seen someone ask recently whether there is a bolt-on rotor upgrade for the E28 M5. I will pass along information learned from Michael _at_ Bavarian Professionals (Berkeley, CA ) at last weekends ///M car festival.

Rather than using 850 rotors, 750 rotors are a direct swap. According to a reliable source, this is the rotor Dinan uses in their upgrade kit. Could save you a lot of cash to buy some 750il rotors _at_ dealer w/your club discount (not to flame Dinan).

As for whether M5 rotors will swap with the E28 535i, the answer is no.

The control valve in the engine compartment fails open resulting in continuous heat. The core can be changed out for ~$35.00. You can check the working of the rheostat by putting a VOM across the leads that feed the valve. As you go from full cold to full hot on the rheostat, the voltage should go from steady 12 volts (valve closed) to oscillating every few seconds when the actual temperature matches the rheostat temperature, to 0 volts in the full heat position (valve open).

If the voltage does not vary as described, the rheostat is at fault. Good luck tearing into the console!. Odds are that it will function as described, in which case the valve is at fault. 4 screws and one connector (plus $35.000) and you should be fixed. The whole valve assembly is $125.00 so be careful that you get the core only.

RE: Victor Fischer <vfischer_at_isbe.state.il.us> >Date: Sun, 19 Mar 1995 09:12:18 -0600 (CST) >Subject: 528e cool heater
>
>Last September I purchased a 1982 528e. In cold weather, when driving >below 40 mph, the heater works fine. Above 40 mph almost no heat comes >into the passenger compartment. In fact, it seems to get colder as the >speed increases.

Sure Victor. The problem is in the heater solenoid control valve. When the internal rubber gasket rips, the valve doesn't leak, but the circulating coolant can be sufficient to keep the valve closed when the modulating electrical control shuts it off, and will even pop it closed without electrical actuation at higher revs. You can get heat back for a while by momentarily putting the car in neutral and allowing the engine to return to idle. If the heat control selector is all the way up, the heat may stay on for some time.

The fix is to replace the guts of the control valve. I've found some shops that propose replacing the entire valve (at around $ 90 + labor), but some of the aftermarket parts houses sell the valve guts for about $ 25. It's a simple 10 minute job involving removing 4 screws, pulling the old valve and inserting the new one. You'll lose coolant unless you drain some first.

Hope this helps!

Paul Reitz (prreitz_at_amp.com)

The first dashboard heater fan on my '85 528e failed around 50K miles. Fix it, I said. Ouch!, I said when I picked up the car -- $325 to replace it!

The second lock-up ocurred around 100K miles. Can't it be lubed, I asked? Nope -- another $325! But this time I asked for the failed part.

The fan assembly has a 1920's look to it, but is really rather flimsy. I lubed the failed fan w/ 3-in1 oil from an oil can with a flex spout. Hooked it up to benchtop 12V supply and ran it.

It was fine! Relubed and ran on the bench a few more times to assure that bearings were liberally doused with oil, and put fan assembly back into the box.

At 150K miles, when the second replacement fan failed, I replaced it with the one I had oiled.

A short while back, that fan started squeaking. Oiled it in place; still running fine.

What I have learned: The bearings are lousy. Oil them from time to time (especially if a squeak develops), and the fan's life should be determined by wear on the commutator, rather than by failure of the bearings.

Larry Swain

>larry
>
> My heater core needs replacing. My shop manual says >I need to remove and discharge my AC unit. Is this true?

Short answer: Maybe not.

I replaced the heater core in my 83 528e over the weekend. Fascinating project. Tear out interior, tear out firewall in the engine compartment. remove 20-30 metal clips holding plastic together...

The good news was I didn't have to remove the AC unit. Instead of removing the heater box as indicated in the manuals, I split the heater box in situ, and removed the heater core. The old heater core failed, because the foam to protect it from chaffing had worn out and the plastic wore through. I wrapped the new one in foam and put it in the heater box, reassembly was interesting, but doable.

I don't know what the dealer charges for this job, but it's probably a bargain. I spent 12 hours doing this job, although I work slowly and took numerous "cursing" breaks.

Instructions for E28 535i (should apply to any E28)

There are two philip screws which attach the top of the fuse box (or power distribution panel as the book calls it) to the bottom of the box. Remove these two screws. You may have to remove the relays above the screws to get at them. Find and remove the fog relay (marked in the owner's manual and the Bentley). Remove the connector in the top part of the fuse panel (it's in the slots that you push the relay in) for the 85 lead on the relay (if you look at the bottom of the relay, the leads are labeled with the numbers 30, 86, 87, 85...so on). The easiest way to remove the connector is to use a very thin flat screwdriver and push on the back of the spade to push the little tab back into the spade so it slides out the bottom of the fuse panel. Drawing below:

| <-- thin screwdriver
|
______ |__________ top of fuse panel
|
|\ <-- push this tab in from above
| to slide connector out the bottom

Now pull the connector out the bottom of the panel by separating the top and bottom halves of the fuse panel. The halves do not separate much maybe 3 inches. Tape this connector up or use shrink tubing. You won't be using this connector again. The next step is to remove the connector of the 85 lead of the high beam relay (this is ground, you might want to test for such) in the same way but you will use this again.

Make a y connector with two leads to fit in the two slots you just removed the connectors from and the third lead to fit in the connector that was connected to the 85 on the high beam relay. Plug the y connector in (slots and the extra lead). Tape or shrink wrap the y connector to previous 85 high beam conector. All that is left is to plug in the relays and test the new feature (fogs on even with high beams on) and put the two halves of the fuse panels back together. TEST!! before putting the halves together.

Instructions for E30 318i (should apply to any E30)

Same as above except disconnect 85 on the fog relay and put the y-connector to the connector on the 86 of the high beam relay (this is +12v when the ignition in the run position) and the 85 lead of the fog relay.

I have also wired my fogs to function as longs as the light switch is in the park or on position but that extra bit is more complicated than I can explain in this media.

How to replace the clutch in a BMW 1983 528e. Or, how Larry spent his Christmas '94 vacation & $350.00 in parts.

My 83 528e is still going strong, with 151K miles on it. The throw out bearing started to grind and make a lot of noise. I could almost live with that, but I could also hear the pilot bearing above the engine noise. That started to concern me. Not being able to stand the thought of getting someone else to do it, I pulled the transmission and replaced the clutch myself. I thought this might make good FAQ bait.

The shop says that this is a 7 hour job. I can believe that if you've done it 3 or 4 times. I spent two full days doing this job. I have a very comfortable garage, complete with machine shop (mill/lathe/welders), and air tools. (and a refigerator with Xmas cookies and beer :)

PARTS:

First, if you're going to replace the clutch, buy the parts mail order. Pressure plate, release bearing, pilot bearing and clutch plate are standard. I would also plan on the Guibo, and the plastic fulcrum point that the slave cylinder leverages off of. Mine was broken, and was the reason that the release bearing fell apart. In any event it's a $2.00 part that can only be replaced by pulling the clutch. I replaced mine with a custom made brass piece (convienent having a lathe). BMW also recommends that most of the bolts & nuts you remove be replaced.
To wit; the 6 Nuts that connect the drive shaft and Transmission the 6 bolts that hold the pressure plate on the 6 copper nuts that hold the exhaust to the header the 4 nuts that connect the rear drive shaft to final drive I have had VERY good response from Maxmillians (see the FAQ) for parts direct from Germany at good prices.

TOOLS:

Besides the usual, you'll need to make or buy a Pilot Bearing Puller. I've seen these advertised by Bavarian Auto Sports 1(800)535-2002 for $30.00. I made mine by machine down an 8" long 3/8" bolt. By putting a lip on the end, and then putting a 3lb brass "slammer" on it, I was able to work it out (hold the slammer at an angle, and work your way around the bearing).

A clutch plate alignment tool is a good idea. I machined one from Delrin. 23mm body with a 12mm stub for the pilot bearing (less a few thousands).

You'll also need a Torx socket. This is a female socket, I think it's the E14 size. This is for the bolts from hell that connect the transmission to the engine.

Safety glasses are nice to keep the crude from falling in your eyes... (My car had lots of crude)

METHOD:

Removal

First, using 4 jackstands, get the car in the air far enough to work under(make sure it's solid). Remove the wheels.

Disconnect battery.

Put a hydraulic jack under the engine, use a block of wood to prevent it from crushing the oil pan.

Remove the exhaust system completely. I took the oppurtunity to recoat the O2 sensor threads. (13mm socket, and 15mm socket)

Remove the shield that covers the drive shaft (10mm socket)

With the transmission in gear, and a partners foot on the brake, loosen the 17mm nuts holding the rear drive shaft to the final drive. These are tightened teutonically tight. A long spanner & hammer worked.

Remove the 19mm nuts holding the Guibo and tranny together. Air drive really helps here, other wise, put it in gear and loosen all before removing any.

Remove rear drive nuts and the center bearing bolts.

To pull the drive shaft out of the tranny was teutonic task. What worked for me was wrapping nylon webbing around the drive shaft and then using my foot to push the driveshaft off. This was an inovation I was really proud of.

Remove the slave cylinder and tie it back up in the wheel well with a coat hanger, or a $.10 welding rod :).

Remove the sensors from the bottom of the tranny - mark/remember which one goes in which hole.

Remove the 17mm nuts and 8mm allen head bolts that hold the starter motor. Yes, it is possible to jam your hands in there. I loosened a couple of heater hoses and the air intake to get more room. A 5" extension on a 17mm socket worked well.

Remove the 10mm bolts that hold the lower sheet metal on the bell housing. While the crude and radiator fluid are idiopathically dropping on your face, use the portable phone to request "Sink the Bismark" from the local country station.

Put a second hydraulic jack under the transmission and remove the rear mounts (13mm socket).

>From the inside of the car, remove the shift boot and pull all the insulation up. Disconnect the backuplight switch, and using a pair of needle nose plyers, remove the circlip holding the shifter. Get a good look at how it goes together. Set aside for cleaning and regreasing.

Remove the shift mount assembly (13mm socket). WD-40 on the threads seemed to ease the abuse that the rubber bushing was taking.

Now comes the fun part:
I'm told that you can remove the engine mounts and lower the engine down 2-3 inches, so that there is more room above the transmission. In any event, I didn't do that. There are 4 torx bolts that connect the tranmsission to the engine. 2 are trival to get, 1 is sort of challenging. 1 is an unmitigated pain. In order to get extra clearance, I did the following. Remove insulation (carefully is optional), place a piece of wood on top of the tranmission and jack it up to crush the firewall/tunnel to get an extra 1" of clearance.

If you lower the transmission, and then lower the engine jack so that the whole assembly tilts backwards, you get a fair amount of clearance. Mine tilted back so that the head almost touched the firewall.

Then, using a universal joint (electrical tape wrapped around the joint helps restrict the movement and stiffens it up - works great, another innovation that I liked). Oh, Torx socket, universal joint, 3 5" 3/8" extensions and a 8" 1/2" extension and a breaker bar were needed. I loosened all, then removed starting with the top. (Truth time, I could'nt believe there was one up there, until the tranmsission refused to seperate. I never actually saw the bolt, I could only feel it. - Swear off German beer).

With a jack under the tranny, ease (with a pry bar) off the tranny. It only weighs about 40 lbs, don't drag it across the floor.

Remove the abestos dust, and look at the flywheel. Any blisters? Gouges? No, great, remove the pilot bearing. Otherwise, machine it or buy a new one.

This is an excellent time to replace the tranny oil and take a break (besides it 8pm, and it's dinner time)

Installation:

Clean and replace/grease the release bearing.

Using the alignment tool, put the clutch plate and pressureplate on.

With a willing partner ease the tranny up to the engine. Be sure to have it in gear (reverse was what it was supposed to be in), and rotate the drive point. This will align the spline so that the tranny can go in.

Start the Torx bolts, and on the three easy ones, tighten all the way down, and then remove 1/2". This gets everything set.

Put in the top Torx. When done, re-call Country station and request "Sink the Bismark".

Torque Torx to 65lbs, they were probably 100lbs from the factory. I was told that this excessive torque is what warps the blocks and causes asymetrical wear on cylinder #6.

Replace small bolts, slave cylinder, sensors.

Replace shifter assembly & reconnect backup light.

Replace driveshaft. Replace rear transmission mount, shielding and exhaust.

Remove hydraulic jacks, replace starter bolts.

Bleed hydraulic clutch. The EZ Bleed is a cool tool and I borrowed one. A must addition to the tool nut's collection.

Reinstall gear shifter - a screw driver and needlenose pliers worked well.

In order to get the cluster out of the car you have to lower the steering column on the 6 series. There are 2 10mm bolts accessable from below. You don't need to worry about the steering box, since there is a rubber guibo (sp?) in the column which provides enough flexibility. As for the light switches. The main (left) switch has to come out with the cluster. The fog light switch can be dismounted from the cluster by first unscrewing the know, block the spindel from turning with a pin (hole is provided in spindel) and then undo the nut with a fork wrench.

Hi,

Just a word on TRXs. I've seen much on the list recently, good and bad (very bad). Below is an example of the last kind that I'll try to explain after addressing the main subject: why buy or not buy TRXs?

First, TRX was patented by Michelin in the 70s (if I remember correctly) as a way to improve tire responsiveness/quickness/control, so mainly handling performance, by increasing and controlling the tension of the radial carcass all the way down to the rim (whereas other tires experience a strong variation in tension of the carcass between the rim and the equator of the tire, at the middle of the sidewall). It worked really well, so well that those tires are still kept as references for responsiveness in handling by car makers such as BMW, Peugeot and Mercedes in internal tests. However, they require a specific rim hook profile, and this is where things got tricky. In order to prevent mismatchs (people putting TRX on standard rims and reverse), which would have been potentially very dangerous, NHTSA and similar European bodies pushed for a metric rim to be used with TRX; this way, no mix could be done. However, when TRX (despite its technical advantages for the era) did not expand because of marketing and patenting reasons, Michelin stopped developing new tires using this concept (I believe around 1985). Hence the profil, tire pattern, and structure of the tire are extremely outdated now, by 15 years or maybe more. Namely, the wear, adherence, noise, bad weather performance (I'm talking normal TRX, not all-season nor snow) all are pretty inacceptable now compared to a newly engineered tire, while the handling is still great on cars that can accomodate its power. The cars on which the TRX was originally fitted are of the E24, E28 generation.

I certainly see no reason for anybody to switch to TRX on a modern car. For those who are stuck with TRX wheels and do not care for the tires as long as they provide performance for money, by all means switch to more modern tires, despite the cost of the wheels. And for the happy few who own a beauty originally issued with those tires and want their car to retain all of its original, specific taste, those have much to gain in keeping their

TRX.

Please do not hesitate to comment,
Francois

1. Low end torque.. as much or more than before.. is LOTS smoother coming up the revs, so...
2. Idle is if anything improved (see next..)
3. Fuel economy... very hard to tell since on 10/1 they put the crap oxy-gas in effect in NJ for the winter. Last year as soon as this garbage started, my avg MPG (by the computer) went from around 21 to 18.. same this year. The reason I can't say exactly is that I only had 2 tanks of gas go though it before I put the chip in (crap gas that is..), and it seemed about the same effect as last year. Since I put the chip in, I'm on my second tank.. the first gave me about 19.5mpg.. the tank now is indicating about the same, maybe a bit higher.. but was lots of high-speed driving so far (some around 70-80mph for an hour or so - 6AM on the Garden State Race(Parkway)Track..

The crap gas also effects the idle.. and so far since the chip has been in, the idle is damn near good.. which last year I couldn't say. I have been using Shell gas, which is supposed to contain techron, which improves idle anyway.. so, your call on this.. it sure ain't worse.
4. Hot/cold starting - seems about the same. Starts fairly easily hot or cold, with a bit of a stumble the first 10 seconds after a cold start...
General running is MUCH improved.. I do tend to give it full throttle fairly often, since it seems to REALLY LIKE this now.. very smooth right to where the automatic shifts it at full throttle (about 6,200 rpm or so.. exact is hard to tell since it happens pretty quickly). Had some passengers in the car this AM - 13 year olds - whose comment was "wow.. this car rules!".. so, take it from there!

I like the chip - and what is interesting is I found my copy of the original sales brouchure for the car, which includes the 528 and M5 - and was looking at the fuel requirements for all of them.. the 528 and M5 "REQUIRE" premium.. the 535 was supposed to run on 87 octane.. so it looks to me like they had retarded the piss out of the timing for the 3.5l engine. Dinan requires that you use 91 octane with the chip "or pinging or knock may occur".. no problem for me, since I always use premium for the extra detergents.