Dad and I finally finished my Iroc last Sunday. Since then, the idle has been at 1500 RPM. I've tried adjusting the TPS and the IAC, but with no success. What else causes a high idle? With the rebuild, we left the AIR crap off, that couldn't be causing this could it? The AIR just puts fresh air into the exhaust right? Could timing cause this? I timed it to 6 degrees BTDC just like the book says (disconnecting that tan and black wire). What else can I do?

 

You might have a vacuum leak somewhere. Double check your runner bolts are tight, and that the gaskets lined up correctly.

------------------
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Well you also can turn your throttle adjustment screw back if everything else checks out, if it hasn't been adjusted before there will be a thin plug in the hole pop it out and there is your screw

 

When I back off the screw, nothing happens. The throttle is as far back as it can go, I guess it was as far back as that from the factory. I'll check the runner bolts tomorrow I guess.

 

I'm having sort of the same problem with my car (stock '87 trans am). It wants to idle at 1200rpm or so even after adjustments. With the iac valve plugged in, idle won't really go under that no matter what i do to the screw. It isn't even touching it right now. Sometimes it will idle all the way down but that is rare. i've checked for vac leaks, but haven't found anything yet.

 

did you check the cruze control cable or the passing gear cable to see if it's to tite, just checking.somthing may be blocking it.

[This message has been edited by MAXGTA2002 (edited June 26, 2001).]

 

When you adjust the IAC, do you follow this procedure?

1) Jump terminals A&B of the ALDL with the ignition in the "ACCESSORY ON" position and leave it for about 30 seconds. This will cause the IAC to back all the way out.

2) Now, before undoing the ALDL jumper or turning off the key, unplug the IAC electrical connector.

3) Now start the engine and with it running, adjust the throttle stop screw until the idle speed gets to 425-450 RPM in neutral.

The settings for the TPS sensor should be 0.54-0.62V with the throttle closed.

If you're doing everything correctly though, I don't know what it could be, sorry.

 

I know that my cruise control cable is not too tight. I've checked that out. Don't know what a passing gear cable is. I'm hoping mine is just something to do with a sticking throttle just off idle and the computer trying to adjust for that. Who knows. I'll keep trying things.

SillyWabbit,
Yeah, that looks like the procedure I followed. Did the IAC and set the TPS. Thanks for the steps though..

 

it's the cable on the bottom, you should have three on the drivers side, your throttle, cruse control and the bottom one is your passing gear. in runs under the plenum to your transmission. push the adjuster button if it's to tite( right behind the bracket).