engine light-missfire - The Unofficial BMW M5 Messageboard (m5board.com)

m5pwr · 3rd May 2001, 13:00

have a 2000 m5 and the car has a problem with the engine light flashing and the car running in limp mode on about 6 cyl. happens under acceleration. has anyone had this problem please tell the case and fix. bmw evertime i take it to them they tell me the #1 cyl missfired. someone said it was software on one of the bb boards but bmw says it is not. i'm getting very frustrated with bmw and this problem...the car does not do it all the time it just does it when it wants to. there telling me that my cold air induction could be the problem (because its not dinan) i think that is b.s. not knocking dinan but they are very overpriced for the market. anyone with any info would be grately appreciated.

Jim Dolan · 3rd May 2001, 13:42

Quote:

Originally posted by m5pwr:
have a 2000 m5 and the car has a problem with the engine light flashing and the car running in limp mode on about 6 cyl. happens under acceleration. has anyone had this problem please tell the case and fix. bmw evertime i take it to them they tell me the #1 cyl missfired. someone said it was software on one of the bb boards but bmw says it is not. i'm getting very frustrated with bmw and this problem...the car does not do it all the time it just does it when it wants to. there telling me that my cold air induction could be the problem (because its not dinan) i think that is b.s. not knocking dinan but they are very overpriced for the market. anyone with any info would be grately appreciated.

Mods give them an excuse. If you modify you have to understand this.

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Jim
07/00 M5 Titanium over Red

AndyMenard · 3rd May 2001, 14:23

m5pwr:

My car is almost 1 year old and I have the Dinan CAI with the Stage II software. What you just described happened to me once (and only once) since I bought my car last June. I wasn't even under hard acceleration when it happened. I was just cruising along at around 65mph when all of a sudden, when I tried to pass another car, it was like it was running on 6 or 7 cylinders and 200 hp had vanished.

I drove into a parking lot, turned off the car... waited about a minute or so... started it up again....and the warning light had gone out and it was back to its normal self again! go figure? And it has never happened again since... I asked my mechanic about this and he said he had seen this a couple of times, and at least one of those times, it was on a bone stock M5. Therefore, it seems the culprit is NOT the CAI and associated software?...

This was the one and only time my car ever had any wierd happenings and it has never happened again. I dunno???

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Andy

2000 Imola M5 / Black Nappa - Titanium Trim

Anzir · 3rd May 2001, 20:01

Same thing happened to me as well. Dealer replaced one of the cats, said it was faulty, and that BMW has been having trouble with their cats on the 8 cylinder cars. That's probably true, since I had to have all the cats replaced on my 1997 740iL.

Teutonaddict · 3rd May 2001, 20:23

Like Andy, this happened to me ONCE, on a bone-stock M5 after about 8K miles. I didn't at the time think to 'reboot' and turn on/off the ignition. Instead, I had the car flat-bedded to the dealership where (1) they couldn't replicate the problem, and (2) the diagnostic read: cylinder misfire. I have not experienced this fault since.

Since this appears to happen to non-modified M5s as well, it's unfortunate your dealership is responding as they are. As Jim says, that's one of the risks of modifying our Beasts (or at least doing so outside the dealership).

There are, however, a number of "aftermarket-friendly" dealerships out there that won't try to screw you just b/c you've got mods. I've found Hank Aaron BMW in Atlanta to reasonable and fair in that regard. Perhaps you could try working with another dealer?

Good luck.

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'00 Carbon Black/Black All-Leather/Sportive
101421

greg · 3rd May 2001, 20:51

Happened to me once too. In my case it was a load of bad gas. Never happened again.

COULD be:

Fuel injector
Bad spark plug

or many other things. It is very UNLIKELY it has anything to do with the CAI, BUT - as pointed out below - mods give the dealer an excuse.

400hpAddict · 3rd May 2001, 22:50

Greg,

That's what you get for feeding your Beast REGULAR! hehehe

-Shawn

[This message has been edited by 400hpAddict (edited 03 May 2001).]

AJ · 3rd May 2001, 23:04

huh? intake's fault? cat fault? are those ppl nuts?

a missfire is anything but that.

it could be:

1. bad plug

2. bad wire

3. bad spark distribution (computer)

4. bad spark distribution (sensors)

5. bad gas (water or dirt in gas)

6. low octane fuel (lower octane eases spontaneous combustion aka knocking and computer tries to retard timing on that particular cylinder which might lead in missfire under certain conditions)

if a dealer tells me that a misfire is due to cai he would lose me as a customer in an instant...

alex
00 m5

rvacha · 3rd May 2001, 23:15

Actually a bad cat can indeed do this. Bad cat causes shift in measured O2, causing DME to shift mixture, and if after a while the O2 hasn't moved back to target, the check engine light comes on. E39 V8 cats more or less fail suddenly as whatever is in there holding the cat guts in place breaks. I have never heard of a cat failure that didn't rattle, so if you don't hear a rattle, its probably not the cat. Ask me how I know....

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143366
'97 E39 540i six speed Aspen/Aubergine <-- Damn fast
'00 E39 M5 Carbon/LeMans <-- Faster

Peter Gutniak · 3rd May 2001, 23:38

Hi,

I probably know what the problem is. It can be one of two things. It does depend though on what date your car was manufactured. If it´s built later than August 1999 it´s probably fault no 2, if not it could be either.

1. Faulty throttle valve potentiometers. You should have the goldplated version, otherwise you will experience the "engine light" and "Emergency program" together with the car only being able to run at appx 50 km/h on any gear. It´s really very easy to fix for BMW. Ask them to look up document 130399(475) in TIS, (Engine in emergency program).

2. Problems with VANOS (the magnetic valves, camshaft sensor, poorly adjusted valvetimes and/or an internal problem with the entire VANOS unit). Ask your BMW technician to check document 114527000 in TIS (VANOS adjustment except tolerance), and he´ll know what to do.

Best regards

Peter Gutniak
peter.gutniak@euromail.se