Finally SES...CODE 35...need help
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From: Lutz, FL USA
Finally SES...CODE 35...need help
been pretty rough lately, solved a bunch of stuff that never threw codes....now tonight it threw a code 35.....the stuff i printed up a while back says that is an IAC fault.
well i had recently replaced the IAC (maybe a month or so ago), so i know it is fairly new. could the new one be bad?? should i try to put the old one back in?? someone give me a clue what to do??
well i had recently replaced the IAC (maybe a month or so ago), so i know it is fairly new. could the new one be bad?? should i try to put the old one back in?? someone give me a clue what to do??
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Joined: Oct 2002
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From: Glasgow Kentucky
Car: 04 Vette
Engine: LS1
Transmission: 4L60E
Axle/Gears: 2.73
check all electical connections to iac as as a loose or corroded connection will set the trouble codes just like a faulty component will.
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Joined: Dec 2000
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From: Lutz, FL USA
vader, yes it is, a 91 3.1.
i hope you asked because it will help you come up with an answer, because if you make fun of me now, i just might go find a short rope and a tall tree
i hope you asked because it will help you come up with an answer, because if you make fun of me now, i just might go find a short rope and a tall tree
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I asked because there is a specified procedure for installing and teaching the IAC position to the ECM. Unfortunately, you cannot simply bolt in a new IAC on a V-6 and expect the ECM to take over control, as is the case on a TBI or TPI. I don't know why, but the guys at Delco Electronics got "creative" with the V-6 control schemes. It coincides with the non-adjustable TPS sensor, where the ECM "learns" the TPS voltage at system startup.
The correct procedure requires that the IAC is installed, then the engine is started, warmed up to operating temperature, and the ECM is monitored for IAC counts. The throttle stop screw is then adjusted to provide between 10-20 IAC counts at hot idle, instead of the customary "RPM method" of minimum air position adjustment on TPI or TBI engines.
You can often get lucky with the installation by just installing a new IAC, but the factory procedure is to monitor the ECM IAC output. If you don't have a means of monitoring the ECM data, you could mark the position of the throttle stop screw as a base reference, then adjust the position slightly to see if the situation improves over a day or two of driving. If not, try adjusting a little more, or try adjusting in the other direction, remembering the base position. This is not very scientific, but may solve the problem eventually.
The correct procedure requires that the IAC is installed, then the engine is started, warmed up to operating temperature, and the ECM is monitored for IAC counts. The throttle stop screw is then adjusted to provide between 10-20 IAC counts at hot idle, instead of the customary "RPM method" of minimum air position adjustment on TPI or TBI engines.
You can often get lucky with the installation by just installing a new IAC, but the factory procedure is to monitor the ECM IAC output. If you don't have a means of monitoring the ECM data, you could mark the position of the throttle stop screw as a base reference, then adjust the position slightly to see if the situation improves over a day or two of driving. If not, try adjusting a little more, or try adjusting in the other direction, remembering the base position. This is not very scientific, but may solve the problem eventually.
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