RE: '84 Corvette, 350 CID with Cross-Fire Injection system (Auto Trans).

[urtoslo]

Joe,

I'm posting this for club member Stewart Fox and will forward any response to him.

Thanks.

Andrej



Car has:

> Replacement motor (Jasper 300 HP, installed fall 2002) plus re-built trans with mild shift kit
> Existing Cross-Fire injection system, with two new Idle Air Control Solenoids (IACS)
> New radiator, cooling fan, '88 & up cooling fan relay, 195-degree coolant temp sensor, 180 degree T-stat
> New MAP sensor
> Hi-performance ignition coil and Accell ignition module

Problem: Car cold-starts easily but immediately goes to idle speed of 1400 RPM. After about 90 seconds, idle will drop back down to 800 - 900 RPM.

I can not seem to find a vacuum leak or sensor problem that would cause or cure the problem. This problem did not develop until about a year before I swapped out the motor. (yes, I have put up with this problem for quite a while now, but thought I could fix it myself). I can also tell that at the higher idle speed, the IACS's are wide open and pulling lots of air past the throttle plates in the injector bodies. I do not have a "driveability" problem after the idel speed drops ie, there are not flat spots or surges of power.

After idle drops back down to normal range, things seem ok, although the idle has always been kind of rough (old motor and new).

I am real curious to learn what the possible cause(s) and fix of this problem are.

Stewart

[joe1968]

There are many diffrent things that could cause this to happen but I would have to see the numbers on a scanner,and the vehicle to start with. I don't want to best guess and send you down the wrong path and have you spend money that you don't have to. Joe

[urtoslo]

Andrej

Thanks for being the relay guy.

My question is: Will it be possible to hook my car up to the scanner during shop-night on 5/25 to try to pinpoint the idle problem?

STF

[joe1968]

Yes, Bring it in and lets see what the numbers are and go from there. Joe