trouble with idle
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Joined: Oct 2008
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From: Redondo Beach, CA
trouble with idle When I start the car, it will go up to 1500, drop down to almost zero, then go up to 1500 again and idle steady. Sometimes (when its cold), it will go up to 1000, then drop down and die if i dont gas it immediately.
Info: ported heads, hotcam kit, zo6 intake, dyno tuned, full exhaust, M6
what could it be?
Info: ported heads, hotcam kit, zo6 intake, dyno tuned, full exhaust, M6
what could it be?
Last edited by nik1703; Mar 2, 2011 at 03:25 PM.
Thread Starter
TECH Resident
Joined: Oct 2008
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From: Redondo Beach, CA
sweet. will do.
on my GTI, cleaning the maf consisted of removing it, soaking it in 99% alcohol for 30 minutes, drying it out, and reinstalling it. is that correct?
Thread Starter
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From: Redondo Beach, CA
I don't believe so because it is only on first start/cold start. after its been running for 30 seconds, idle is solid at 1100.
Has it always been this way or just start? There is tuning for cold start and warm idle separate in the PCM. My car did the same thing on cold starts until I got a better tune.
If the idle is set so high on a mild cam car, I wouldn't be so quick to rule out the tune if it's behaved this way the whole time.
But yes, clean the MAF and all throttle body sensors with cleaner from the parts store. Might also check around MAP sensor/intake/all hoses for vacuum leaks.
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Thread Starter
TECH Resident
Joined: Oct 2008
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From: Redondo Beach, CA
With a hot cam kit? I would think it would idle perfect at 700-800rpm.
Has it always been this way or just start? There is tuning for cold start and warm idle separate in the PCM. My car did the same thing on cold starts until I got a better tune.
If the idle is set so high on a mild cam car, I wouldn't be so quick to rule out the tune if it's behaved this way the whole time.
But yes, clean the MAF and all throttle body sensors with cleaner from the parts store. Might also check around MAP sensor/intake/all hoses for vacuum leaks.
Has it always been this way or just start? There is tuning for cold start and warm idle separate in the PCM. My car did the same thing on cold starts until I got a better tune.
If the idle is set so high on a mild cam car, I wouldn't be so quick to rule out the tune if it's behaved this way the whole time.
But yes, clean the MAF and all throttle body sensors with cleaner from the parts store. Might also check around MAP sensor/intake/all hoses for vacuum leaks.
Aside from the hotcam kit, it has ported heads, z06 intake and k&n FIPK kit.
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Start by trying to clean the IAC or Idle Air control valve. It is the top one on the throttle body and these can cause erratic idle if they are dirty or worn out. Mine had some black carbon on it causing a very minor idle issue, cleaned it and the problem was gone.
Thread Starter
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Joined: Oct 2008
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From: Redondo Beach, CA
Ok. So I cleaned the IAC (sensor on top right of throttle body) with a paper towel (it had a bit of black **** on it) and I also cleaned the MAF with MAF cleaner. Didn't fix the idle issue.
Someone mentioned something about a MAP sensor?
Someone mentioned something about a MAP sensor?
It's on the back of the intake. You can make sure its not leaking by spraying starting fluid or something similar around it while the car is running and see if the idle changes dramatically.
Then clean it like you did the others.
Then clean it like you did the others.
