ctd

Hi,
I have searched the web with no help on this topic. I have a 1987 Iroc-z with 6700, yes 6,700 mile. Car runs brand new, except for this ridiculous warm start issue. Cold start no problem, flick of the key and it fires right up.

It is not a starter since it cranks perfectly fine.

The fuel pump seems to always be working and sounds normal, but I would think it would not start even in the morning if this was the issue, car has low miles.

Changed coolant temperature sensor, which I read somewhere else, but that did not work.

Injectors are not leaking.

Idle's fine

No Smoke

Car runs like it came off the showroom floor other than this. There is nothing funky going on otherwise. Car went through public inspection and guys said the car isn't even broken in yet. So this is annoying.

Everything is original, hoses belts, plugs, etc..... Nothing is dry-rotted and is garage kept.

Some where I read Fuel Pressure Regulator, does this sound correct? Anything I read online about the regulator symptoms do not point to this issue.

Someone must have had this issue.

Any help is appreciated.

Fred SS

iTrader: (3)

I'm just throwing this out there, but is it possible the cold start injector is injecting fuel when the car is warm as well as cold. If the thermal switch fails closed then it will inject fuel while cranking even when the motor is warm. Could that extra fuel cause hard starting when warm? One way to verify if that is it is to remove the connector from the thermal switch when the motor is warm and see how it starts.

Bob88GTA

iTrader: (2)

^^^^What Fred said.

And that switch is on the front of the intake with a connector that looks like a injector connector

rickjae1

Any luck with this? I have an 87 TPI IROC (27,000 miles car like new) with several indications that I have extra fuel coming from somewhere. It idles rough, stalls at the stop light and bucks at low throttle. The injectors all read 17 ohms, cold start is 4 ohms and everything holds pressure after I shut the key off. I unplugged the cold start injector and car runs much better. Still troubleshooting the cold start circuit but I suspect the switch. I'm going to run it awhile with the cold start injector unplugged to see how the car performs. Not sure if I should spend the 100 + dollars on a new cold start switch or try and eliminate which requires a new chip.

ctd

Hi,
mine runs new with no bucking or anything like that and even idles perfect. Mine is only a warm start issue, which I have not had a chance to look at the cold start injector. The issue you are describing sounds like a bad spark plug. I would change the plugs in it.

ctd

So same thing happening with the warm start. After trying to start it today after it was warm it just cranked. If I turn it off and then try to start it right away, no problem. If I let it sit for about 20 minutes, cranks for a bit before it starts and stars rough. After it's started no problem idles fine and runs new.

If it starts by pressing the gas pedal to the floor what does that mean? I read somewhere that doing this stops the injectors from spraying fuel. I can't seem to find that post again.