Idle questions

HJB1988M5 · 6th January 2006, 16:30

I have a 1988 M5 that I have had for 15 years I thought I new most of the quirks. Recently though a new one has developed. When I start the car cold the idle goes to 2,500 RPM and has a significant miss. After 60 seconds or so the idle goes to 600 RPM. When the engine finally warms up say 10 minutes it idles normally at 950 to 1000. I have never had it do this before and have no clues. Any help appreciated.

PiersR · 10th January 2006, 13:30

Quote:

Originally Posted by HJB1988M5

I have a 1988 M5 that I have had for 15 years I thought I new most of the quirks. Recently though a new one has developed. When I start the car cold the idle goes to 2,500 RPM and has a significant miss. After 60 seconds or so the idle goes to 600 RPM. When the engine finally warms up say 10 minutes it idles normally at 950 to 1000. I have never had it do this before and have no clues. Any help appreciated.

Try disconnecting the cold start sensor (blue connector by the fuel rail in the centre of the TB's) If it still does the same it may be worn out. I run mine disconnected due to various mods and it idles at 650 when cold untill it warms up. At the very least it may be part of the problem...

Piers