Subject: Re: Misfiring and catalytic converters -Reply
From: Atul Chhabra <atul_at_Basit.COM>
Date: 08 Jan 1998 10:02:37 -0500
Chris,
Thanks for the info. I have been experiencing a rattling and resonating kind of sound from under the disco when driving on a rough road. The dealer has looked at just about everything under the car. They have replaced a muffler heat shield, tightened muffler mountings, tightened brake dust guards, replaced the rear shock bushings, ... Everytime they tell me the problem is fixed. But of course it isn't. When the rains stop, I will get under the disco and inspect the catalytic converter for rattles. (Yes, it's been rainy and foggy in New York for the last three days. We have hardly seen any snow this winter.) Hope I can trace the problem.
--Atul Chhabra
'95 disco
atul_at_basit.com
Chris> Atul:
Chris> I had to replace the catalytic converter (y-pipe) on my 92 Chris> RR earlier this year. My understanding is that you will Chris> *hear* if there is a problem. In my case it was a a gradual Chris> and then near-constant rattle at idle and low speed. At Chris> first I thought the rattle came from the engine, but I Chris> eventually traced the sound by using a big screwdriver as a Chris> stethescope to the right hand converter. The rattle (pieces Chris> of loose catalyst) got progresssively louder and more Chris> annoying. After balking at dealer price quotes and being Chris> turned away at local (MD/DC/VA) Midas shops, I ordered the Chris> new y-pipe from Special Interest Car Parts (best price by Chris> several hundred dollars) and changed the pipe myself. Took Chris> a hell of a long time since I'm only learning the nuances Chris> of rover repair, but I did the job right and saved enough Chris> money to turn my attentions and rapidly diminishing Chris> checking account to the leaking radiator, the faulty abs Chris> brake pump, the oil pressure warning light... etc etc
Chris> Love my Rover
Chris> C. Petite Middleburg, VA
Date: Thu, 08 Jan 1998 08:29:42 -0800
From: "Tony V. Sawyer" <tvs_at_hydrogeologist.com>
Subject: Re: Land Rover Discovery Tire Pressure?
Mavromatis wrote:
> I was reading the LR manual and it states 26psi for the front and 36psi for
> the back.
> I have all four set to 38psi because I was (is) getting 12mpg on a 98 Disco.
> They were previously set to the 26psi front and 36psi back. Will this harm the
> tires if I put more air in them? The tire says max air is 44psi. Should I put
> more for better mileage?
> Danny
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> Danny
> 98 Oxford Blue Disco
Danny:
Running pressure that is too high will give you a rougher ride and wear out the center quicker. To determine the optimal tire pressure for a given tire and load, use the chalk line method as follows: 1) Fill the tires to some arbitrarily high pressure (38 psi is good), 2) draw a straight line across the tread of each of the tires (perpendicular to the sidewall), 3) drive in a straight line for ~ 100 feet, 4) examine the chalk lines. If the line is gone only in the middle, the tire is overinflated. Reduce air pressure a couple of psi and try again. If the line is gone only near the edges, the tire is underinflated. Add air and repeat process. If the line is gone altogether, the inflation is good for the load in the vehicle. Write the numbers down for future reference.
Tony Sawyer
'95 Disco "Volante"
Date: Thu, 08 Jan 1998 11:28:49 -0500
From: Chris Petite <cpetite_at_cov.com>
Subject: Re: Misfiring and catalytic converters -Reply -Reply
Atul:
To clarify: my experience with the catalytic rattle is that the sound is loudest at idle when there is significantly more pressure in the exhaust system-- and is not particularly audible at speed or related to how rough the road happens to be. The rattle you describe may not be be related to loose catalyst, then. Hopefully this is the case and you just have to hunt down exactly where metal is unfortunately meeting metal. On my old Bronco, it was a brake line knocking against the frame. Good luck.
Chris
> I think the regulations about what you can do with your
> catalytic converters vary from state to state, but I do have
> a good friend at the local midas shop here in Mountain View
> California who can replace the units for $100 each plus labour.
The Midas shops in will replace Rover Cats for about the same price.
>Does anyone know the capacity of a standard RR alternator on running
Hella's. (how many )
I believe the older RRs came stock with a lucas 80 amp. Newer ones have a MM 85 amp alternator I believe. Since hte lucas units do occasionally die :), some older models also have the MM.
I have a rebuilt 80 amp and the only problems I have had are with hella (55/60 watt) headlights, 2 Hella 500 fogs, wipers and front and rear defrosters on at the same time. The defrosters appear to detect the lack of power and don't come on at the same time. I can see the dash lights dim when I hit windows or defrost, too. Of course the alternator will not put out its max power at idle, either.
What I would like to know is how much power the RR uses just running (with and without aircon). Anyone got an idea?
You could then add up all the lights, defrosters, etc and see how much you could run at once. watts/volts =amps, right. So, if my calculations are right, your 1000s are 200 watts, your 550's are 110 watts, your headlights are 120 watts for a total of 430 watts. At 12 volts (should it be 14?) thats about 35 amps. Gotta count all the little 5w side lights, dash lights, plate lights and all too. plus the EFI, wipers, defrost, etc. The 2 extra 550s would add another 9 amps or so.
Hi Atul,
>How can one tell if they have a shot catalytic converter? On Christmas
>eve, I was far from home and the disco started running extremely rough
>under load. I called LR road recovery and they told me to drive it if
>possible to my destination which was about a hundred miles away, where
>they arranged for a dealer to check it out on the 26th. Turned out to
>be bad spark plug wires. (The disco had just undergone a cold start
>upgrade. The dealer should have checked the condition of the wires
[ truncated by list-digester (was 12 lines)]
>caused damage to the catalytic converter. What do I look for to
>determine if everything is ok?
Hmmm... to be honest, I don't know. The cats need to be very hot to work (which is why driving around in tall, dry grass with a Disco is a bad idea). I can only imagine that if they're not, they'd get clogged up with residue and create even more backpressure in the exhaust. Not sure though. Think you need a specialist... :-(
Tim
The rebuild can be done in a day, providing you have everything you need to hand, and it all goes according to plan!! The article I referred to is in the July 1996 LRO, I could possibly scan and mail to you direct if neccessary. Taking the box out is easy, but it is fairly heavy and awkward to manouvre out from under the vehicle. On the bench, getting the drop arm off can be difficult, you need a puller - or a visit to a friendly garage with the right tackle. I was lucky to remove mine with a cheap two legged puller. Dismantling and rebuilding the box is straightforward, but you must have a clean area to do it, and have washed the outside of the box off with kerosene first. Any sort of dirt inside the box will kill it very swiftly. Again I was lucky, in that the internals of my box did not show any appreciable wear (even after over 100K miles), so I was able to replace the seals and put it all back together. Th missing seals that I referred to in my previous post were on the spool valve. I suspect that if I had gone to a steering box specialist I might have been able to buy these separately, but I needed the vehicle back on the road quickly so decided to chance it without replacing them. Costs are about 10 UKP for the three bolt box or 30 UKP for the four bolt box (count the bolts on the box top cover, around the adjuster) plus a few litres of ATF. When compared to 150 UKP for a rebuilt exchange item, I think it is worth a go. Let me know if you need more detail.
Mike Stoddard
'86 RR with Mazda Diesel Power
I am not sure if this helps, I have not read the posts too clearly but.... I have had roblems in the past with the fuel running too rich and causing the catalytic conv to break down. Also, once this starts to hapen your mufler will slowly(or not so slowly) start to 'burn up'.
William Pittman
Atul,
My Discovery had a rattle in the exhaust that I thought was the heat shield.
It turned out it was a baffle in the exhaust. I have 45K on the odo. I had a
Ex***oer that had water in the gas and was misfiring until I got it home. I
had to replace the catalytic converter. The local muffler shops all wanted
about $200. With all the CB thread. Where is the best place to install an
antenna on a Discovery?
Greg Edwards
95 Discovery