92 gsx needs to warm up for 15mins before i can drive it???

[gsxferko]

Well I've been posting things about this 92 gsx I just bought, and I've gotten it running great, just the only new "I don't know if its a problem" that I'm having is, when I first start it, I have to let it warm up completely before driving it... if I try to put it in drive or reverse and his the gas, the car just stalls...

Does anybody know why its doing this???


Thanks!

 

[steve]

Since you just bought it your in the lets kind all the hacks the prior owners did mode.

Maintaining the idle in and out of gear on an AT is the job of the ECU, ISC (Idle Speed Control servo), and FAIV (Fast Idle Air Valve) in combination with the BISS (Basic Idle Speed Screw). The ECU looks at the IPS (Idle Position Switch) and inhibitor switch to know that the throttle is closed and if the trans is in park/neutral or in gear. It looks at the ECT (Engine Coolant Temp) to know if the engine is cold or warm.

If the IPS is open it doesn't try and manage the idle speed. If it's closed the ECU tries to maintain the idle speed by opening and closing the ISC.

When the engine is cold the FIAV works to provide extra air to cause the engine to idle around 1500 RPM. As the engine warms up the FIAV starts closing off it's bypass and the ISC takes on a bigger roll until the engine reaches about 122F where the FIAV is closed and the ISC and BISS control the speed.

There is a common problem with these cars where extra air leaks past the throttle plat at idle the the car idle high or surges. People often attempt to fix the problem by removing or blocking off the FIAV and ISC. Once they do that the car will no longer fast idle when cold or maintain the idle speed when the transmission is put in gear on the automatic. That may be going on with your car.

It may also be possible that your ISC is bad or that the drivers of the ISC in the ECU are damage and the ECU can't use the ISC to control the idle speed.

 

[gsxferko]

Wow, that was more than enough info, thanks a lot...

And I bought it bone stock off a old lady {original owner}!!!

Ill have to look into it, once the car is warm, it runs and idles flawlessly

Wow, that was more than enough info, thanks a lot...

And I bought it bone stock off a old lady {original owner}!!!

Ill have to look into it, once the car is warm, it runs and idles flawlessly

 

[Fabian]

I had a buddy who's car was doing the same thing yours is too. I traced it down to the dinky little lower injector seal. It had gotten real hard and cracked and was letting ALOT of air out. As soon as I replaced them, he never had the problem again.

 

[steve]

Given that an "old" lady owned it I'd start looking at the simpler maintenance issues like getting the capacitors in the ECU fixed and checking the ISC for open or shorted coils and replacing the dried out seals and o-rings, and for cracked or broken wires to things like the IPS.

Does the engine fast idle when it's cold?

 

[gsxferko]

Well I did, injector seals, plugs, wires, timing belt, and all other simple maintenance...

Yea, it idles at about 2500 till it gets almost to running temp.

 

[steve]

That's about 1000 RPM too high. If the IPS was working that would normally cause it to be surging.

 

[gsxferko]

ill have to check it out, i just need the car as a daily driver for winter, i just want to make sure that im not going to have any problems with it that i may be able to prevent