Dies while running

[93shortbox]

I just bought this truck its a 93 4 cylinder, 5 speed the truck runs great for 30 minutes or so. Then it just stops running without any sign like it was turned off. If I wait a couple minutes it will fire right up like normal. I really need to fix this asap because this will be my new DD. The truck has new fuel filter, both coil packs, plugs, wires, and crank sensor. The truck was lightly hit in the bed underneath the gas door I thought because of the accident it might have messed up the fuel pump but its running at a constant 32psi at idle and at about 3k it drops to about 29psi. I was told that is normal. Could someone please point me in the right direction I need to get this thing running right so I can tag it.

 

[BRUTUS_T_HOG]

fuel pressure is low. it should be 40psi.

whats more important is.. what is the fuel pressure when it dies? you need to find out exactly what you're losing when it dies.

a good way to test this is to wait until it dies and try to supply propane or starting fliud

 

[modelageek]

I just bought this truck its a 93 4 cylinder, 5 speed the truck runs great for 30 minutes or so. Then it just stops running without any sign like it was turned off. If I wait a couple minutes it will fire right up like normal. I really need to fix this asap because this will be my new DD. The truck has new fuel filter, both coil packs, plugs, wires, and crank sensor. The truck was lightly hit in the bed underneath the gas door I thought because of the accident it might have messed up the fuel pump but its running at a constant 32psi at idle and at about 3k it drops to about 29psi. I was told that is normal. Could someone please point me in the right direction I need to get this thing running right so I can tag it.

when it dies you need to figure out if it is a fuel or spark issue..ou can try and start it with starter fluid when it dies and see if it fires. also pull the vacuum line off the fuel pressure regulator on the fuel rail, there should not be fuel in the vacuum line... what is the fuel pressure koeo? how many cycles does it take to build up pressure. how much does the pressure drop in 5 minutes with the truck off.....

 

[93shortbox]

Alright truck idles at a constant 32psi and if i blip the throttle it jumps to 40psi and if i hold it open it will go back to 32psi. When i let off it will drop to 30psi then it will go back to 32psi. When it dies it just shuts down like its being turned off and jumps to 40psi when its off. Also i wonder if it could be another bad sensor or even a bad computer and there is no check engine light on. Befor i forget no gas comes out of the vacuum line off the pressure regulator.

 

[modelageek]

Alright truck idles at a constant 32psi and if i blip the throttle it jumps to 40psi and if i hold it open it will go back to 32psi. When i let off it will drop to 30psi then it will go back to 32psi. When it dies it just shuts down like its being turned off and jumps to 40psi when its off. Also i wonder if it could be another bad sensor or even a bad computer and there is no check engine light on. Befor i forget no gas comes out of the vacuum line off the pressure regulator.

after you turn the truck off for 5 min how much does the pressure drop.....when you do the koeo test how man cycles to get it to full pressure

 

[93shortbox]

After 5 min the pressure drops 1-2psi. What is the koeo test.

 

[modelageek]

koeo=key on engine off.

 

[93shortbox]

Koeo test 40psi im about 99% sure there is nothing wrong with the fuel pump.

 

[Bryan22]

fuel pressure is right on. I would have the ignition control module checked. could be it's overheating and failing after a while. then once you let it cool off a couple minutes the truck will fire back up.

your local parts stores can check the module for free. have them test it 4-5 times in a row.

 

[modelageek]

Combing. The 2 posts above next time it will not start check for spark. If no spark have ICM checked

 

[93shortbox]

It was the ICM. Thanks for the help. It was a lifesaver.

 

[93shortbox]

Just put the new ICM in now it cranks no start. I have tried leaving the battery unhooked for about 30 min then starting it but that didnt work any ideas?

 

[modelageek]

Just put the new ICM in now it cranks no start. I have tried leaving the battery unhooked for about 30 min then starting it but that didnt work any ideas?

did you put all the screws in including the hard to reach ones. They are grounds and the truck will not start if they are not installed

 

[modelageek]

Just put the new ICM in now it cranks no start. I have tried leaving the battery unhooked for about 30 min then starting it but that didnt work any ideas?

you need to determine if it is spark or fuel. check the plugs for spark or spray starter fluid into the tb and see if it fires up.......

 

[93shortbox]

I feel stupid i didnt do that. Facepalm. Im going to give that a shot.