legacycentral bbs

Hi All,

I am having an issue with the idle on my '93 SS. You start the car up and it instantly jumps to 3,000rpm. If you unplug the IACV it will idle down a bit, but still remains high. The only code I am getting is 24, which is the IACV. I have swapped my throttle body with no change, and I changed the IACV motor with no change.

any thoughts? I'm pretty much stumped at this point.

Did this happen all of a sudden or did something change?

The fact that you have an IAC valve code would seem to indicate there is an issue in the electronics/electrical piece of the IAC valve. If you replaced the IAC valve solenoid and nothing changed I would suggest checking the wiring as there may be an issue, which is causing the problem.

Check out the diagrams in here and check the continuity of the wiring with a multimeter from the ECU to the IAC valve connector. It should be 0 ohms or close to 0 ohms.

https://www.main.experiencetherave.com/ ... C_Diag.zip

I went from no high idle when starting the car cold and the car running rich (per wide band) all the time, letting off throttle car will not lean out. Then the engine harness got pulled on and now I have an idle that sits at 2,500 rpms, you touch the throttle and the car wants to “stumble”, the car is still running rich as well.

I’ve checked resistance in the engine harness and everything seems ok. I was leaning towards an ECU issue at this point. Tips for checking resistance in harness back to ECU?

You need to use the wiring diagrams and check the resistance of each sensor/pin going to the engine back to the ECU pin. You can d/l the manuals/diagrams from me.

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