I just bought an 89 GTA. The guy i bought it from said that the car had some engine problems once it warmed up. I just replaced all the sensors and tune up stuff and put on headers and cold air intake.

I took it out today and for the first minute it ram awesome and got to 120 really fast, then i had to slow down. I idled for a little while, then tried it again at it ran like ****, it was chugging and ran like the timing was off or it was running lean, but just 60 seconds before it was running great. After it warmed up the exhaust smelled foul and nasty, not like gas, but maybe like gas and anti-freeze, it did not smell sweet like anti-freeze, but maybe once it goes through the combustion chamber with the gas maybe thats what it smells like. It also did not want to restart. But it did not overheat, it was only at 180 degrees.

The only difference between when it ran bad and good was engine temp and about 60 seconds. Does this mean that it is a cracked head or blown gasket. The oil looks clean and so does the anti-freeze.

 

Maybe a bad CAT?

 

Is there white smoke comming from the exhaust, that will definetly mean coolant is leaking in.

 

The Cat is what i thought at first, but right now it is an open y-pipe, so that is not it, plus it didn't do it when it was at like 150 degrees, only when it was at like 180 degrees. I did not see any white smoke, but the guy i bought it from noticed white smoke.

Would there be anything else that would make a difference between 150 degrees and 180 degrees, it doesn't seem like it does it all the time either, in fact now it is having trouble starting, very random if you ask me.

And no trouble codes either.

 

If you suspect the heads do a compresion test on the cylinders that tell if it has leakage in the cyclinder. You sure the injectors are getting enough fuel pressure thats another area I would look at.

Dan

 

The fuel pressure to the rail is 50 psi, i put on an AFPR. Next weekend i am going to pressure test the coolant system, to see it there are any internal leaks.

 

Could it be my ignition module or something, once it warms up it seems to be either running retarded (ignition) or maybe lean. But i don't think it is fuel. Although even if it was the ignition, i don't know if that would account for the foul smelling fuel. But maybe the fuel is kinda bad, and that is the smell.

It runs fine and starts fine when the eingine is not fully warm.
Once is is fully warmed up it runs like crap and will not restart until it cools down.

 

Any other ideas?

Doesn't run good when fully warmed up, and if you turn it off, it won't restart till it cools down, then runs fine for a little, then the cycle continues.

 

could my fuel pump be going bad? Once it gets hot?

Or could the fuel injector drivers be going bad once the car runs for a little while, a couple of the fuel injectors have low resistance, and maybe they are causing the fuel injector dirvers to go bad.

 

So what your saying is, when its in open loop, it runs great, but when it warms up and enters closed loop, it runs like crap?

So. Why dont you have a scanner on this thing? Seems like a bad o2 sensor to me.

-- Joe

 

I replaced the o2 sensor and i am not getting any trouble codes. i don't know if it is just open loop vs. closed loop, it seems more random than that.

My fuel injector resistances:
1-17
3-17
5-17
7-4

2-10
4-17
6-17
8-17

Maybe it is the fuel injector being so low.