Over reving

[rix444]

'95 with v-6. when I start it up, it revs to 3500+. This s a new developement, but getting worse. Used to only rev to 2000 then settle down after a while. Now I'm just shutting it off.

Already tried removing both small cables to the 'butterfly'. No difference. Are the injectors staying open too long? Too much fuel pressure? I'm at a loss for ideas.

Thanks,
Tom

[4kQuad]

You are most likely fighting a vacuum leak. Look for a little black rubber line that is not hooked up right or at all. Listen for a whisteling sound, that would be air leaking making that sound.

If you know what the throttle body is look real well around it, after the butterfly at the gaskets and stuff.

The cars computer controls the rpm's pretty much, but if air is getting in the computer, IACV can't stop. The RPM's run high.

[rix444]

I'll have to do this visually. Can't let it rev long enough to listen for a leak.

[Bjornboy81]

Does it stay at 3500 rpms? Your Idle Air Control Valve might be bad and suck in the open postion.

[rix444]

Stay at 3500? Who knows, I shut it down immediately. A couple months ago it would start at 2200 rpm and stay there for about 40 seconds, then idle down. I'e let it sit in my driveway until now. At these speeds, I'm not risking it, but it may be an extension of the prior problem. I'll check the valve.

[Bjornboy81]

first off, I see you have 3400 listed but you have a '95 GAGT...did you have an engine swap or is that a misprint? Second idleing at 3500 rpms isn't going to hurt the engine. There is a rev limiter that kills fuel delivery when it's revved in park or neutral that's set to 4000-4500 rpms, so you're ok with 3500. Try starting it and see how long it takes to settle down.

[adamD]

iac probably stuck open or bad, when they fail they move to full open. you can try blocking air flow into the throttle and see if it goes down. iac would compinsate for a vacuum leak by moving out 3500 rpm would be one hell of a leak also. check the iac

[rix444]

now that I knew what to look for, found a couple hoses that had been taken off. No more rev'ing. thanks

now if I could only get rid of the knocking. time for a new engine.

[rix444]

and the engine is a 3100