New to me - car stalls often...lack of backpressure?
10-01-2007 | 01:48 AM
#1
Thread Starter
Pro
Joined: Dec 2002
Posts: 502
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From: Dana Point, CA
New to me - car stalls often...lack of backpressure?
My Boxster track car (several other threads on here have pics/info) stalls constantly when I'm just moving it around and getting it in the trailer, etc - I have to keep a foot on the throttle just a bit to keep it from stalling. It has straight pipes and custom headers, so it has lots of flow, but little to no backflow. The timing and ECU have been tuned, of course, so perhaps that has something to do with it? Or would it be a disconnected vacuum tube somewhere?? Ideas?
I haven't had the engine up to temp yet, really, as the longest I drove it was about 2 miles, on the street, and not really letting the engine get anywhere near 4k because of the noise
I haven't had the engine up to temp yet, really, as the longest I drove it was about 2 miles, on the street, and not really letting the engine get anywhere near 4k because of the noise
10-01-2007 | 02:31 AM
#2
Pro
Joined: Mar 2002
Posts: 587
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From: Redondo Beach, CA
Apart from the MAF sensor which I mentioned previously, there is an Idle Control Valve (I think it was called) that controls the idle. BUT, what you speak of is EXACTLY what my car did this previous POC weekend at Buttonwillow. After the race, it wouldn't idle at all. I finally got it started after about 10 tries by keeping the revs up, before I could load it onto the trailer. If you have access to a loaner MAF sensor, it's a REALLY quick swap and will answer your question immediately. Otherwise, search out the idle control valve. BTW, the mechanic initially thought my problem was that (ICV), until he spun the engine up. When you throttle the car, does it rev up smoothly or does it stumble a bit? Mine was stumbling as I would rev, running really rich and sometimes back firing?
Dylan.
Dylan.
10-01-2007 | 08:52 AM
#3
Burning Brakes
Joined: Jan 2002
Posts: 1,050
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From: Malvern, Pa.
I just replaced my MAF -- same symptons -- you can disconnect it and the car will go into limp mode to see whether it's any better -- but that will throw the computer codes (MAF, ABS, and PSM for some reason) and you'll need to get them reset. If you've removed the cats you probably are ignoring the check engine light right? Good excuse to get a Durametric code tool. It helped me fix my MAF problem and not miss any time at the track.
10-01-2007 | 12:15 PM
#5
Burning Brakes
Joined: Jan 2002
Posts: 1,050
Likes: 0
From: Malvern, Pa.
www.durametric.com
Read the codes -- if you have a MAF code, then you've found your problem. If not, try disconnecting the MAF and see if it's better. With the Durametric you can clear the codes yourself.
