Won't run warm
Thread Starter
8th Gear
Joined: Aug 2011
Posts: 8
Likes: 0
From: Grapevine tx
Won't run warm
I bought a 91 C4 that has been sitting for over 2 years. It didn't run when I bought it, found that it had a bad fuel pump, I replaced it. Now, it will start when cold, runs fair, but as soon as it starts warming up, it dies, sounds like it runs out of gas. Usually it won't re-start till it cools completely off.
Checked the fuel pressure, 39 psi, good according to the book. Checked for codes, none present. I did pump most of the gas out of the tank when I replaced the pump, but there was still some left. It did smell pretty bad.
Any suggestions would be greatly appreciated...
Mike
Checked the fuel pressure, 39 psi, good according to the book. Checked for codes, none present. I did pump most of the gas out of the tank when I replaced the pump, but there was still some left. It did smell pretty bad.
Any suggestions would be greatly appreciated...
Mike
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
I bought a 91 C4 that has been sitting for over 2 years. It didn't run when I bought it, found that it had a bad fuel pump, I replaced it. Now, it will start when cold, runs fair, but as soon as it starts warming up, it dies, sounds like it runs out of gas. Usually it won't re-start till it cools completely off.
Checked the fuel pressure, 39 psi, good according to the book. Checked for codes, none present. I did pump most of the gas out of the tank when I replaced the pump, but there was still some left. It did smell pretty bad.
Any suggestions would be greatly appreciated...
Mike
Checked the fuel pressure, 39 psi, good according to the book. Checked for codes, none present. I did pump most of the gas out of the tank when I replaced the pump, but there was still some left. It did smell pretty bad.
Any suggestions would be greatly appreciated...
Mike
Beyond that, the injectors were junk from the factory so plan on those being bad after a 2 yr soak in ethanol. O2 sensor probably needs to be replaced...the shift to closed loop cannot happen with a tired o2 sensor. As it warms it'll die. What are the stored DTCs? pull 'em and post 'em.
Then d/c battery for 30 sec and try again...
Mice in the wire harness...
MAF? Temp sensors checked?
TPS set?
Vac leaks checked and fixed?
Base timing set correctly...clean dist cap & wires.
Lots to do to a motor that did a 2 yr stretch in alcohol.
Poor O-rings...thats abuse.
Most important of all, you need a FSM before even thinking about a real diagnosis.
Do a search here for the link and order today.
Thread Starter
8th Gear
Joined: Aug 2011
Posts: 8
Likes: 0
From: Grapevine tx
Thanks for all the suggestions, I have some things to check. There are no stored codes, and the fuel pressure stays at 39 psi, BUT right before it dies the pressure goes up a couple of lbs.....
I DO think there were critters under the hood, I may have a mess on my hands. It seems odd that there are no stored codes........
I DO think there were critters under the hood, I may have a mess on my hands. It seems odd that there are no stored codes........
Last edited by roadking319; Oct 21, 2011 at 07:56 AM.
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
Obviously there could be a bunch of things wrong but I would suggest a simple approach as suggested by the sailor. leesvet hit a lot of areas for sure but your search will be simplified by knowing fuel or spark.
No codes is kinda strange.
No codes is kinda strange.
Thread Starter
8th Gear
Joined: Aug 2011
Posts: 8
Likes: 0
From: Grapevine tx
I have a OBD2 scanner, that obviously wont help. I did flash the codes on the info screen, nothing... Checked the injectors, 5 of them appear to be partially shorted, Guess that's the next step.....
