1994 5.7 chevy 1500 pickup truck. Trucks runs great but there is one thing that isnt right? It will not fire up when starting again until I let it sit for 20mins than it will fire right up again and runs great once running. Whwn its cold or even little warm it starts up great. Whwn its hot or just plain warm up after a 10mile drive if I cut truck off it wont fire up again till cool. PLEASE help

 

what type of fuel delivery system tbi or multi port spyder injection?
the symtons sounds like injector leakdown; fuel into the cylinders.... if you have port injection; put a fuel rpressure gauge on the fuel line, prime the system, they watch for a pressure drop.

 

This is not normal and needs to be corrected ASAP.

 

The fact that he has to let sit for 20 minutes before a restart does not sound like fuel injection system losing prime but does sound like an ignition spark problem. I would give a good look see inside the cap and rotor. I am betting the module has to cool down before the restart and that the film heat sink under the module is non existent.

 

injector leakdown into the cylinder will cause a hard restart when warm...it floods the motor. sitting for 20 will clear it up as the engine cools and the fuel evaps. its not the only possibility but its certainly one.

 

I gotta agree with that. I also would like to see what fuel pressure is at KOEO and at start at idle and while driving, with the gauge taped to w/s.

 

I'm no expert, but is there some input that tells the computer that the engine is cold or warm? I have a (not GMC) vehicle that would not start warm until it sat for 30 min. Too rich mixture because the defective sensor was sending a cold engine input. Just a thought......

 

sure..its the engine coolant temp sensor. if open or shorted it would set a code and turn the mil light on. being that this vehilce is obdI...there are no rationality checks. to confirm sensor operation the op could check sensor readings with an odb1 scan tool and confirm on cold start up it reads close to ambient temp.

 

My tahoe runs great other than the fact that it sounds like water sloshing in the heater. I had this problem last year, and it was because there was bubbles in the coolant after it had been refilled. This year, it sat for about a weak, and I noticed a leak coming from the transmission cooler screw on the radiator. There is again a sloshing sound in the heater, and now it only runs on high. Any help or suggestions would be greatly appreciated.

 

My tahoe runs great other than the fact that it sounds like water sloshing in the heater. I had this problem last year, and it was because there was bubbles in the coolant after it had been refilled. This year, it sat for about a weak, and I noticed a leak coming from the transmission cooler screw on the radiator. There is again a sloshing sound in the heater, and now it only runs on high. Any help or suggestions would be greatly appreciated.