'93 D250 will not rev above 1100 rpm without sputtering. Any help?

[ORS243]

Hi,

I am not a mechanic... not even close. However, I like learning how to fix my truck when feasible. I thought I would ask some education before poking at things I don't understand.

I need some help finding the cause of a recent breakdown. The truck died while on the road while doing about 50 mph. No sputter, no advanced warning, just dead and heavy. Had it towed to a friends and he found a broken wire behind the throttle linkage. Once repaired the truck started and will idle smoothly but will not rev above 1100 rpm (tachometer reading). Once above 1100 it starts missing. The more throttle the rougher it runs. It feels like it is starving for fuel.

Added information: During the diagnosis he bench tested the fuel solenoid and it works. It is what led him to check the power supply and find the damaged wire. He thinks the cause might be air in the injection system but it idles nice and smooth. Any thoughts?

Thanks,

Bill
1993 D250. Stock, 327,000.

 

[DavidC]

First thing to check/replace is fuel filter.

Dave

 

[ORS243]

Thank you for the suggestion. Went to start it today and it seemed to run better at first. Got it up to 1500 rpm then it sputtered and reverted to the previous performance. I'll let you know if the filter fixes the problem.

 

[RWherley]

find a fuel pressure gauge some where and make sure your lift pump is still good

 

[ORS243]

Took it to a mechanic and they changed the pump and filter. They did not like the cheap lift pump that was on the truck and recommended changing it. Anyway, no change in the original problem. Now he wants to rebuild the injection pump and injectors. I am fine with that if it will fix the problem. He does not sound 100% confident that it will. What ests do you do to verify the injection pump is bad? Any help is appreciated. Would like to get a definite "bad injection pump" answer before I spend the $'s.

Thanks,

Bill

 

[AEdelheit]

Have you verified the voltage at the fuel shutoff solenoid?? I have seen cases where it was only getting lets say 8 volts , enough it would partially open but not fully, also dont overlook the ground. Usually pumps will give some sort of warning not just die out of the blue, could be air getting in the fuel but sounds like electrical.

I doubt it is an intake issue but never hurts to check the air filter and make sure something is not blocking air flow.

 

[ORS243]

Thanks for the reply.

The mechanic said he had tested the electrical and found it OK. I'll ask for specifics of what was done. Just rebuilt my PCM about a month ago. Could it be the cause of the problem again?

 

[ORS243]

Here is an update. The mechanic says he has it fixed. He checked the voltage to the fuel solenoid as suggested and it was OK. While "open" he checked the solenoid and the plunger was not operating as intended. He replaced the solenoid and it runs like a champ again. Funny thing is that the solenoid was replaced about 6 months ago while I was having problems with the PCM. Crossing my fingers and taking her on a road trip.

Thanks for the help.

Bill