Engine/Transmission (1994 - 1998) Truck dies when warm

[MatthewPark]

A buddy of mine just picked up a 94 auto. It starts up and runs fine until it warms up, then it shuts off and won't start again until it's cold. The fuel shutoff solenoid on the injector pump seems to be working, at least it moves when it should. I've searched, and I'm stumped.

 

[MatthewPark]

After a day of messing with this truck, I think there are 2 problems. I have to assume the injector pump needs work, and the fuel shutoff solenoid needs replacement. Sometimes it pops up all the way when you try to start it, sometimes it just jerks for a second and stays down. Either way, if I manually hold the lever up, the truck won't run warm, period.



While cranking the warm engine, there is fuel getting to the pump. There is fuel leaving the pump out of the banjo fitting on the front of the pump between the pump and the head. There is no fuel leaving any of the lines, with the fuel shutoff solenoid lever in any position, up or down.



When the truck is cold and runs, there is almost no fuel going to the #5 cyl, and not much seems to be going to #6. I say this because when you crack the injector line on #5, it only leaks a tiny bit (barely enough to wet the fitting), and the tune of the engine doesn't change a bit. When you crack #6, it leaks a tiny bit more than #5, and the engine tune changes a tiny bit. The other 4 cylinders' lines squirt fuel all over everything when I crack the lines, and the engine starts starts misfiring in a very noticeable manner. Also, when I am driving the truck, it shakes like hell (consistent with gas motors I have dealt with misfiring).



What do y'all think?

 

[Howard Durand]

You might want to try a new overflow valve. It is under the banjo fitting you mentioned.