Idling high. Not TPS or IAC. Help! HPT log.
12-19-2011, 05:27 PM
#1
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Idling high. Not TPS or IAC. Help! HPT log. I am so sick of these idling problems! What could be causing this? It was running perfectly the other day!
The only code is for high idle. The TPS and IAC do not show to be open. And it is idling at like 2000 RPM or more.
Bone stock Gen 3.
Thanks for the help.
The only code is for high idle. The TPS and IAC do not show to be open. And it is idling at like 2000 RPM or more.
Bone stock Gen 3.
Thanks for the help.
12-20-2011, 09:48 PM
#2
See how high your MAP readings are? I've seen this before on a car I did a header swap on. The issue was the engine was sucking in air through the MAP port on the back of the intake where after removing the AIR crossover tube completely from the car for race headers I unfortunately didn't get the MAP sensor plugged in all the way. The high idle code is from the car pcm trying to hit the commanded idle rpm and being WAY off over a set amount of time. Give all your hoses leading into the intake a check over. Hope this fixes your issue!
12-21-2011, 12:08 PM
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Thank you. I won't get to look at it until this weekend. I will look for vacuum leaks. Fortunately I have a spare engine so I can swap over whatever part is causing this.
Is there anything else I can log to help confirm it is a vacuum leak?
Thank you so much for the reply.
Is there anything else I can log to help confirm it is a vacuum leak?
Thank you so much for the reply.
12-22-2011, 10:44 PM
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your vacuum is too low, that is what i think is wrong with your idle. most common cause would be a vacuum leak, maybe a hose or an intake leak. with a normal engine (stock and mechanically healty) vaccum should be between 18in and 22in. use a gauge not the map reading to verifiy actual vacuum. goo news is vacuum leaks are usually cheap to fix. good luck.
12-26-2011, 08:40 PM
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Final bump before I go look at it tomorrow.
Do the fuel trims suggest that it's a vacuum leak? If it was an intake gasket leak, wouldn't one bank be more out of whack than the other?
Just throw me some more ideas so I can get this thing fixed tomorrow.
Thank you
Do the fuel trims suggest that it's a vacuum leak? If it was an intake gasket leak, wouldn't one bank be more out of whack than the other?
Just throw me some more ideas so I can get this thing fixed tomorrow.
Thank you
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12-26-2011, 09:36 PM
#8
On The Tree
I had this problem in my camaro (4th gen though) and it was the wire through the firewall that connected to the TPS was shorting out on the firewall. I had to get the wire and put some heat shrink on it along with more tape to put padding around it. Only thing was it wasn't just high idle...the car would die occasionally when the wire hit the firewall when driving. Just throwing out any more ideas to help you out.
12-27-2011, 06:18 AM
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Since my MAF shows the same reading of 3.71 at 2200 and at 2400 RPM, as the idle fluctuates, does that confirm a post-throttle body vacuum leak?
And thanks Car Guy. I went through the same thing a few months ago with similarly damaged TPS wiring causing false readings. Fortunately, it is fixed now, and the TPS reads correctly again.
And thanks Car Guy. I went through the same thing a few months ago with similarly damaged TPS wiring causing false readings. Fortunately, it is fixed now, and the TPS reads correctly again.
12-27-2011, 02:56 PM
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Well, I'm here looking at it, and now it's not doing it.
Also the MAF reading is .8 instead of 3.0+, so apparently when the high idle problem happens, the MAF is seeing the increased airflow. So that suggests it isn't an unmetered vacuum leak. But even when I max out the IAC manually on HPT, I can only raise the idle to 1200. What would cause it to go all the way up to 2200?
Could the EVAP pump be sticking open?
Also the MAF reading is .8 instead of 3.0+, so apparently when the high idle problem happens, the MAF is seeing the increased airflow. So that suggests it isn't an unmetered vacuum leak. But even when I max out the IAC manually on HPT, I can only raise the idle to 1200. What would cause it to go all the way up to 2200?
Could the EVAP pump be sticking open?
