Iac sensor problem?
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 908
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From: Waipahu Hawaii
Iac sensor problem?
O.K heres the low down, I did replace the IAC sensor but, it was a used one off of a friends car (Steve40Th's) Every time in the morning or starting the car for the first time during the day, the car surges up and down for a few mintutes while it's warming up, sometimes it'll stall out, sometimes it wont! after a while, (when it's warm I guess) it'll clear up and run fine! What can be the problem? I tried while the car is running to unplug the IAC, and the car's idle does'nt change or anything!? does'nt get worse or better. How can I test the IAc (if theres such a thing) to see if it's faulty? Mahalo in advance.
[Modified by Hawaiian Punch, 12:23 PM 12/16/2002]
[Modified by Hawaiian Punch, 12:26 PM 12/16/2002]
[Modified by Hawaiian Punch, 12:23 PM 12/16/2002]
[Modified by Hawaiian Punch, 12:26 PM 12/16/2002]
Melting Slicks
Joined: Oct 1999
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From: Houston, Texas FEAR THE BONES
2023 C5 of the Year Finalist - Modified
Re: Iac sensor problem? (Hawaiian Punch)
There is a Tech Tip on resetting the IAC valve, but it is for LT1/4 cars. It might be same for L98s, I just don't know. Might be worth a shot. :hat
Le Mans Master
Joined: Dec 1999
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From: And on the fifth day, subpoenas were served to Obama senior staff
Safety Car
Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
Re: Iac sensor problem? (Hawaiian Punch)
Check with Steve to see if he has "tampered" with the IAC valve. One of my manuals states that tampering with tha idle speed adjustment may result in premature failure, or improperly controlling engine idle.
The test procedure follows:
1. Visually check the connector for proper connection, and free of corrosion.
2. Unplug the IAC connector and check resistance between the IAC terminals. Resistance between terminals A and B and terminals C to D should be 40 - 80 ohms.
3. Resistance between A to C, A to D, B to C and B to D should be infinite.
4. If resistance is within spec, check the IAC circuits back to the PCM for continuity.
5. If the valve and circuits are functional, the computer control module may be faulty.
Source: Chilton Manual
The test procedure follows:
1. Visually check the connector for proper connection, and free of corrosion.
2. Unplug the IAC connector and check resistance between the IAC terminals. Resistance between terminals A and B and terminals C to D should be 40 - 80 ohms.
3. Resistance between A to C, A to D, B to C and B to D should be infinite.
4. If resistance is within spec, check the IAC circuits back to the PCM for continuity.
5. If the valve and circuits are functional, the computer control module may be faulty.
Source: Chilton Manual
Safety Car
Joined: Feb 2002
Posts: 4,212
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From: Sun City West Az
Re: Iac sensor problem? (Hawaiian Punch)
Kalani,
While you have the meter in your hands, ohm out the injectors. They should be with in 1 ohm of each other. You may have a bad solenoid or injector problems..also look at the EGR to be sure it isn't open while warming up "open loop".
While you have the meter in your hands, ohm out the injectors. They should be with in 1 ohm of each other. You may have a bad solenoid or injector problems..also look at the EGR to be sure it isn't open while warming up "open loop".
Thread Starter
Burning Brakes
Joined: Jun 2002
Posts: 908
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From: Waipahu Hawaii
Re: Iac sensor problem? (Hawaiian Punch)
UPDATE- This is what I found out guy's! now the idle was low so I tried to raise it up by screwing the little idle screw in, that made it run bad, heres what I realized what I was doing wrong, The IAC is like a controled air leak right?! When the idle was to low the IAC could not raise it back up, it was trying, thats why the weird idling at times, and the surgeing of the engine, it was trying to adjust it's self, but could'nt, Now by me raiseing the idle manualy, the TPS would end up being out of wack, so I still would get a weird idling, and this constent back and forth thing was'nt geting me anywhere! Solution. I turn the ignition on, unpluged the IAC, turn the ignition off then turn the car on, I adjusted the idle with the idle screw...of course, and turn the engine off, plug the IAC back in, now I unplug the TPS, and used my meter to adjust to what I called for, in this case I put it at .56 volts, pluged it back in, and Walla!!! the perfect idle!! I hope this will do it for this problem, I've driven it around and so far so good! Mahalo (thank you) for all your help and support!! :cheers:
