My IROC still has long cold hard starts even after having fuel pump and fuel filter replaced. It worked great for about three days, then it started behaving like its usual self. Car behaves like its not getting any fuel when engine is cold. It starts after a long crank, sputteres, and dies a couple seconds later. It will start on third try, behaves the same before and after fuel pump/ filter swap. I just don't get it. Someone help!!


Parts replaced:
Fuel pump
Fuel filter
Fuel pump relay
Fuel pressure regulator
Bosch type 3 fuel injecors
Cap and rotor
Spark plugs and wires
Tps and iac (to specs)
Coolant sensor
Egr is still working
Knock sensor
Oil pressure sending unit
All electrical pigtails
Ecm
Maf sensor
Maf relays
Vacuum lines (no leaks)

 

Have you tried lightly applying the throttle while cranking? Also, do you have access to a fuel pressure gauge? If so, a reading when cold would be very helpful

 

Thanks for quick reply. Fuel pressure checked out, but ill check again. Car bogs down when I press the pedal. Once it warms up the car behaves normally.

 

I seen the parts you have changed just thought id let you know I did the same on my rs tbi had problem like that I had to change the fuel filter again do o bad fuel and trash and replaced a few lines she wakes right up and pures in the morning now and were talkin 30 degree starts idk if that helps just know dirt and junk can hide anywere in these old rides of ours

 

Thanks I'll check lines soon I hope.
Anybody else?

 

When it warms up does it run better or can you not keep it running that long?

 

Warm, it runs really strong, starts and runs like if its new. I'll need to check fuel pressure again, but I know its going to be good.

 

Mine is doing the same thing. I'm lost!

 

I am not a TPI expert, but, since it works fine warm but not cold, I woulds say check your choke...or in your case I believe it's the cold start injector. Ohm across it and let us know if it's reading correctly.

 

Thanks Ozz, but 89's don't use cold start injector.

 

Ok, like I said, not a TPI expert by any means...carb guy here. It just sounds like a cold start issue...so choke related. What do you have that is choke related on your car?

 

Can you hear the fuel pump kick on for a moment when you first turn the key to RUN ???

 

Yes, I do hear fuel pump kick in.

 

Temp sensor??.

 

Any codes?

 

Temp has been replaced and its not throwing any codes.

 

Not for nothing,but do a compression/leakdown test on this cold.

 

Welll I took car to a mechanic. He checked compression, fuel pressure etc. He couldn't find anything wrong. He's know checking the maf which I already replaced twice. Iroc always starts with it disconnected, even if the engine is cold. My knowledge is limited, but can a faulty distributor or timing chain cause a cold hard start? The timing chain is original and I don't think distributor has been replaced.

The car started great for about 3 days before it starting acting up again cold hard start.