jerkiness on cold days - The Unofficial BMW M5 Messageboard (m5board.com)

jmott · 31st December 2002, 22:17

Ive noticed some jerkiness when accelerating lightly when first starting out on cold mornings. It seems worse going up hill. This is on a 2000 M5, and Im wondering if this is a sign of clutch slippage, or possibly an issues with the dinan cold air intake and/or chip.

anyone else have this problem?

Scubabob · 31st December 2002, 22:30

I have a stock 2000 M5 that exhibits the same problem. Below freezing, I have to accelerate very slowly for the few minutes or so in order to avoid jerky power output from the engine. After that it's fine. I have no idea what the cause is of this. Bad fuel atomization? Bad mixture? I use Mobil Premium gas. In zero degree weather, I let the engine idle for a minute before starting out. It doesn't give me any extra trouble.

Bob

Paul S · 31st December 2002, 22:32

me too. done it since new. it's better with sport button on though.
i spoke with a e46 m3 owner who had the same issue.

jmott · 31st December 2002, 22:39

interesting, wonder if its due to the clutch being freezing or just engine management issues

Digi · 1st January 2003, 00:22

The only jerkiness in my car is when I am sitting behind the steering wheel. When I get out of the car, the jerk is gone. My friends keep on pointing out this problem, but I never listen.

Sydude · 1st January 2003, 00:36

I believe what you guys are talking about is caused by the computer setting a higher idle speed when the car is warming up from a very low temperature. This causes a different engine speed differential during a shift than you are used to, hence the "jerkiness".

This is further exacerbated when going up hills, as a heavy flywheel and the higher idle causes an even greater disparity in engine speed than usual because the vehicle loses speed more rapidly between shifts on a hill.

IMHO, anyway!

Sydude · 1st January 2003, 00:38

Quote:

Originally posted by Digi
The only jerkiness in my car is when I am sitting behind the steering wheel. When I get out of the car, the jerk is gone. My friends keep on pointing out this problem, but I never listen.

Funny!

dwasifar · 1st January 2003, 16:58

Quote:

Originally posted by Sydude
I believe what you guys are talking about is caused by the computer setting a higher idle speed when the car is warming up from a very low temperature. This causes a different engine speed differential during a shift than you are used to, hence the "jerkiness".

This is further exacerbated when going up hills, as a heavy flywheel and the higher idle causes an even greater disparity in engine speed than usual because the vehicle loses speed more rapidly between shifts on a hill.

I don't think that's what they are talking about. I have this condition too in my 2000, and it's not something that happens during shifting; it takes place when the car is in gear and being lightly accelerated. It's kind of a jerky surging feeling.

wilmus · 1st January 2003, 19:39

I have a 2000 M5 and it does it also. But only once when I'm first starting out and never feel it again till it's cold. It never seemed to effect anything else.

mfspolo · 1st January 2003, 21:38

might be because the oil is still hard