Crossfire in Fast Idle

[82X-Fire]

First off, great site! I am an invader coming from a Camaro site but this is the best site I have found for info on the crossfire setup.

I have a problem with a 1982 Camaro. The fuel pump went out and I replaced it. After starting the engine it is stuck in fast idle mode. I have replaced a bunch of hoses and resealed the TBI to make certain there are no vacuum leaks. I was told that resetting the IAC might cure it but am not sure if I havethe correct procedure for doing it. I have disconnected the battery for ten minutes, no change. I have tried turning the ignition switch on-off three times, no good. Also, the car has a ECM from an 84 and a Hypertech chip in it.

I definately want to keep the crossfire setup in the car. My plans are to do away with the anemic 305 and put in a 350 or 383 under it.

 

[redvett]

My first guess is the wrong fuel pump and too high fuel pressure, did you check the PSI?

 

[82X-Fire]

did think of that but aren't all GM mechanical pumps about the same PSI?
Will have to put in a tee to check it.

 

[KANE]

First off, great site! I am an invader coming from a Camaro site but this is the best site I have found for info on the crossfire setup...

First off-



Don't worry about not having a Vette- you are always welcome here!

If you are serious about keeping the Crossfire- the folks on this site can definitely help you maintain it.

So... lets start with the basics. Are there any codes that you are getting? I'm curious about the root cause to the fast idle myself.;squint:

 

[nelson84]

No vette;squint:

:nono


















I guess we will let it slide just for you



I had a 83 Z28 when I was a teenager. Got alot of:naughty: in that car. Wasn't the fastest car I've owned but had alot of fun in it :dancenaughty

 

[82X-Fire]

Thanks for the warm welcome! Yes, sorry but no Vette. I do work on them occasionally (I work at a restoration shop), however a person standing 6' 8" does not fit well in a Vette. Actually I have a customer with a big block 4 speed Vette that I cannot drive because of long legs. Automatic & T-tops for headroom, lol.

Back to the finicky crossfire. I checked the fuel pressure (12psi) & removed the IAC units and cleaned them. The MAP sensor checks out alright. The computer has no codes stored. I am beginning to think that something failed the same time as the fuel pump. Tomorrow I am going to start plugging all vacuum lines, want to preclude any leaks in things like the brake booster, cruise control, etc.

 

[nelson84]

My 84 vette had a fast idle and it was the coolant temp sensor. The sensor was shot and it told the computer that it was really cold out and the computer made the engine run rich and it had a fast idle about 2400 rpm, once I replaced that it now runs perfect 650-700 rpm at idle. Thats the grade 1 way of explaining it sorry, I'm not that great with cars.

 

[82X-Fire]

Good point Nelson, I will check on the temp sensor. I just tried plugging the air ports to the IAC units. With a shop rag in them the car slows right down to idle. When I remove either one the engine speeds up. I am thinking that the computer is not talking to the IAC or the computer sees something that is incorrect, like a temp sensor gone bad.

Does anyone know the procedure for resetting the IACs? I have checked the initial depth setting but would like to confirm home position.

 

[82X-Fire]

Well guys, I think it is fixed.
And the award goes to,,,,,,,,,,Nelson84!
For some strange reason the coolant sensor went the same time as the fuel pump.
My first attempt at scanning the codes was with a small code scout. Once I hooked up our Solus scanner I could see that the sensor was out of range.
Thanks guys!

 

[nelson84]

I win, I win,:harhar









:booty