I have an erratic idle and some other symptoms on my M50. Not to go into too many details I have some technical questions which I'm hoping someone might be able to answer.
1) Whilst installing the engine (when it was working) I noticed that it will run quite happily (Limp mode I think) with the MAF sensor disconnected (electrically). What other sensors does the ECU use to make ICV adjustments when the MAF is disconnected??? (There is no intake pressure sensor that I know of)
2) What could cause the revs to stay high for 1-2 seconds after the throttle is released (closed), I've tried 2 different TPS's and 2 different ICV's. I'm thinking vacuum leak in manifold post-ICV. (Symptoms get worse with MAF disconnected).
M50 Idle - Technical Question
Moderator: martauto
-
DanThe
- E30 Zone Team Member
- Posts: 28649
- Joined: Sat Sep 10, 2005 11:00 pm
- Location: Staffs
Do you have all sensors connected? You need to make sure its out of limp before worrying about idle speeds etc
-
gudgeon
- E30 Zone Regular
- Posts: 475
- Joined: Sun Jan 27, 2008 11:00 pm
- Location: Didcot
The question is, how does the ECU control idle speed when the MAF is disconnected? I know it does, 'cos I've tried it.
Think I've solved the problem now, just curious about non-MAF operation.
Think I've solved the problem now, just curious about non-MAF operation.
-
Brianmoooore
- E30 Zone Team Member
- Posts: 49359
- Joined: Mon Jan 10, 2005 11:00 pm
Idle speed control is essentially a simple feedback loop from the ECU's engine speed signal to the ICV. MAF doesn't come into it.