I have a 93 2500 x.cab 4x4 6.5 auto trans , After it runs for a while (in the warmer temperatures of the year) it is almost impossible to start. I have no idea what is the cause. I checked the bottom of the filter housing, and di not find fuel in the valley pan. Please if you have any ideas it would be greatly appreciated!Censored:banghead:

Liftpump or OPS bad ?

No fuel in the filter housing, than the liftpump doesn't pump. Why ? Because it is bad, the OPS is bad or a break/short in the harness.


Cu,
Sven

Try pouring water over the IP when it is causing grief.....does it start? If so, the head/rotor clearnace is in question and the IP needs to be changed...

Liftpump or OPS bad ?

No fuel in the filter housing, than the liftpump doesn't pump. Why ? Because it is bad, the OPS is bad or a break/short in the harness.


Cu,
Sven

X 2.
check OPS first.

I'd check for lift pump operation, when it's not starting crack the fuel bleed valve open and see if the lift pump is working. The valve is next to the thermostat/upper radiator hose on the water crossover. Open that valve, and turn the key on. You should hear a prrr from the lift pump and some fuel should come out. If it dosen't, check the filter housing bleed. Might need a fuel filter. Also the 92-93 have the 4911 mechanical IP, they are known to wear to have excessive head-space and not want to pump when hot. Pour tap water over it, don't drench the engine but trickle it oer the IP when it won't start. Maybe a gallon at most should do it. If it starts, then the IP needs replacement or rebuilding. Also if that's it, you might try to turn up the IP 1/8 turn that might get you going for a while before replacing the IP. Good luck.
Don

The injector pump is new, I started it the other day and it started "cold" fine, now while the temperature here is cool it will not give me any troubles. When summer rolls around in San Antonio, Tx then I start having the troubles. The injector pump has not seen a years woth of use. By lift pump do you mean the electronic fuel pump on the frame?I do not have much experience with the Chevy diesel, the old 6.9 f word I have experience with. I did not want to drop the f bomb in a Chevy forum. There is fuel in the filter housing. I am wondering if the lines running under the intake in the valley are dry rotted (again) and they are expanding in the heat and losong prime? What is the gizmo on the (passenger)side of the injector pump? Could this be my culprit?

Liftpump is the electronic fuelpump in the frame rail below driver seat.

OPS - Oil pressure switch -> controls the liftpump. It is located below the fuel filter housing. If it fails, the liftpump doesn't work and it is no start or really hard to start the engine.

Check these things first and than come back, tell us the results and we'll see how to go on, if problem not solved.


Cu,
Sven

Your injection pump is bad. 92-93 injection pumps had bad heads in them. Your "New" pump has a defective head and rotor. Needs to be updated with the newer version.