Installed new heads and now have idling problem

[viper98885]

I just installed my new heads but now have a problem. I replaced the head bolts with ARP head studs, otherwise everything else was a direct replacement. Now that the job is complete, I am idling at about 2300 RPM's. I have checked the vacuum lines and listened for vacuum leaks, sprayed brake cleaner around gasket mating surfaces to find a change of idle and have found nothing. The battery has been disconnected for about about 2 weeks because I did a clutch swap at the same time as the heads.

I have driven the car about 50 miles to see if the idle will drop, but it has not changed.

Also, I disconnected the JET chip so that the computer can relearn its data without interference.

If anyone has any suggestions, lemme know.

[rockotman]

Is the engine fuel injected? If so, check to make sure that the idle air bypass valve is functioning properly. If it is not hooked up right, or if is leaking slightly, it will cause the idle to go high on you.

[Andy H]

I may not be much help but, I had a similar problem with a truck once. I had throttle body and intake off for rebuilding and cleaning. Anyway I put it all back together and it idled around 2,500 rpms. I couldn't figure it out at the time so I took it to a mechanic it turn out to be a wrong gasket between throttle body and intake. It had cause a vacuum leak and was dumping gas in the intake. Your problem sounds to me like a vacuum leak or fuel being dumped in intake. Are you getting any trouble codes? It could be the TPS or IAC sensor. Hope this helps some.

[viper98885]

Only trouble codes that I am getting is the IAC code that states that the IAC cannot set idle RPM...I have 2 spare IACs here so I swapped them out and it didn't make a difference.

As far as the gaskets, I used new gaskets and they are the same set that I always use. All of em looked familiar.

[Bird_Of_Prey]

There is a vacuum line that goes from the back of you intake manifold to your brake booster, make suer that's on snug.

[viper98885]

<blockquote>quote:</font><hr>Originally posted by Bird_Of_Prey:
There is a vacuum line that goes from the back of you intake manifold to your brake booster, make suer that's on snug.<hr></blockquote>

Yup, good and tight with new clamp. I am going to take the upper manifold off again and seal it with some Indian Head gasket sealer...it was always a good seller when I worked at Autozone.

What do you guys think of doubling up the intake manifold gaskets?

[Magnus]

I would not use RTV or double up on gaskets..

Locate your leak with a mechanics stethoscope.

If it is in fact a gasket, clean both surfaces very well and use a new gasket and torque down to spec.. the gaskets should not leak and should DEFINATELY not need to be doubled up.

Good luck!

Also, if you put your hand over the TB and close it completely and the car still runs you know its getting O2 from somewhere else (the leak).

[ August 22, 2002: Message edited by: Magnus ]</p>

[viper98885]

Leak is fixed...turned out to be a crappy upper intake manifold gasket. Car runs awesome now...idles at about 900 RPMs and has gained a lot more power.

Thanks to all that replied.

[camaro97]

Hey Josh,
Congrats on fixing the high idle. I konw it was really drivin u nuckin futz. later

Matt
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