Idle surge from 650-2000 rpm
#1
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Idle surge from 650-2000 rpm
Hi everyone:
I have a 99 C2 that has an idle surge problem. No codes, goes from normal idle up to 2000 rpm, turning the a/c on sort of stabilizes it, but it stays high idle at around 2000. The throttle body is clean, and the m.a.f. sensor is as well. I am dealing with a clutch issue, but this started after that.
The threads i looked at did not show the idle going as high as mine.
Thanks in advance for any help.
Paul
I have a 99 C2 that has an idle surge problem. No codes, goes from normal idle up to 2000 rpm, turning the a/c on sort of stabilizes it, but it stays high idle at around 2000. The throttle body is clean, and the m.a.f. sensor is as well. I am dealing with a clutch issue, but this started after that.
The threads i looked at did not show the idle going as high as mine.
Thanks in advance for any help.
Paul
#4
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Thread Starter
Thanks for the replies. Cable is clean and free, cleaned the throttle body and idle control valve, turning the a/c on seems to smooth it out but idle stays way up, removing the oil fill cap seems to effect it (rule out aos),and stock flywheel. Plan on plugging it in to scan on Tuesday. It revs perfectly and smoothly, looked and sprayed for vacuum leaks, none found. Stumped
#5
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Recently, having had my TB out, I started the car and had a high idle. I closely checked my TB and saw the throttle cable was holding the TB open so the engine was not returning to idle. Turns out the cable had not fully snapped back in the back of the plastic guide on the TB. I wrapped my fingers around the cable and gave it a tug, heard it snap into the guide and that was it. Simple enough. If your car has a throttle cable, undo it to see if the car idles properly. If so, then check to make sure the throttle cable is fully seated in the guide and is not binding.
#6
I had a similar issue on the pedal end of the cable. I ended up taking the gas pedal apart and greasing things inside. If I recall it was a real PITA to get the gas pedal back together.
http://www.renntech.org/forums/topic...al#entry157971
http://www.renntech.org/forums/topic...al#entry157971
#7
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Because it surges on its own I wouldn't imagine it's the peddle or peddle cable - linkage.
More like a sensor or vacuum leak but my knowledge is extremely limited in this scenario .
More like a sensor or vacuum leak but my knowledge is extremely limited in this scenario .
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#8
Thanks for the replies. Cable is clean and free, cleaned the throttle body and idle control valve, turning the a/c on seems to smooth it out but idle stays way up, removing the oil fill cap seems to effect it (rule out aos),and stock flywheel. Plan on plugging it in to scan on Tuesday. It revs perfectly and smoothly, looked and sprayed for vacuum leaks, none found. Stumped
#9
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Agree with Ahsai. Leaning towards a problem with the ICV. Did you follow these instructions for cleaning the TB and ICV? http://www.pelicanparts.com/techarti...y_Cleaning.htm
The only way to clean the passages for the ICV is to fully remove it from the TB. Is that what you did? Also, are you sure the electrical connector to the ICV is fully seated?
The only way to clean the passages for the ICV is to fully remove it from the TB. Is that what you did? Also, are you sure the electrical connector to the ICV is fully seated?
#10
Except that the scenario described by two responders would create a "disagree" between throttle position sensor and actual throttle butterfly position. That could definitely cause a surge.
#12
Race Director
Did you ever scan for diagnostic codes?
My idle hunted drastically when I had a bad plug/coil pack. Once I replaced the plugs and coil packs, that smoothed right out.
Fuel pump and fuel filter check out?
Have you tried running with the MAF disconnected to see if the problem resolves with no MAF?
My idle hunted drastically when I had a bad plug/coil pack. Once I replaced the plugs and coil packs, that smoothed right out.
Fuel pump and fuel filter check out?
Have you tried running with the MAF disconnected to see if the problem resolves with no MAF?
#14
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Thread Starter
Pulled the throttle body and ICV and cleaned them. The air box was out so the TPS, ICV, and MAF sensors were all disconnected. Throwing no codes which makes no sense. But it was running and surging idling from idle-2000. Used a snap on acanner
Thanks for the replies and help, it is appreciated
Thanks for the replies and help, it is appreciated