My truck is a '91 D250 2WD 5.9 Liter Cummins Intercooled


I have a problem. My truck just quit and won't start. Up until this moment, it ran fine, started everytime with hardly any work from the starter. Then nothing. We changed the fuel filter, and lift pump, only becuase I havn't ever changed it yet, and still it won't start. We have enough fuel pressure all the way to the injector pump, but when cracking the injector nozzle, there is not enough pressure up there. We pulled the fuel cut solenoid, and bench tested it, and noticed that it was sticking closed with the plunger not fully returing. So I got a new fuel cut solenoid and we replaced it. The truck was able to start and run for about 20 minutes, but ran really rough and we had to give it plenty throttle to keep it going. After about 20 minutes, it died, and wouldn't start again.

My mechanic and I are stumped at this point. What else can we check? Is there anything electrical that maybe we forgot to check? Do I need a new injection pump? How can I isolate it so I know for sure that it is the injection pump? Where is the best price on a rebuilt injection pump? I know they are expensive.

Please help! Any and all ideas are welcomed. I need my truck back on the road. I am stranded without it.

Thanks.

Jeff

 

Crack all the injector nozzles and try it, if/when it starts run all the air out of it. Might try closing all but one after getting it started and then run one at a time loose until you see no bubbles. Sometimes getting all the air out is a PITA...

Good luck to ya.

 

Hi,
Mine did that and I found the return springs in the injection pump were broken.
Mike

 

i was playing with my pump one day and removed the collar off the fuel screw and when i put it back in i did not thred it far enough so my truck wouldent start up and it cranked super rough untill i floored it and held it there and she finnaly started so i had to run the screw in and it perked right up...maby your screw vibrated loose??

 

Where is the fuel screw you are referring to? Are you talking about the idle adjustment screw on the throttle linkage? Or is it something actually on the injection pump itself? Please explain further....
Thanks.

 

If you haven't been messing with the fuel screw, that's not your problem.

You have checked to make sure you have a good connection at the shutoff solenoid, the factory connector has a tendency to get loose and cause trouble.

If that's good, and you have good fuel supply to the pump, and you've tried bleeding the injector lines and it still won't go, then I'm with Mike - you need a pump rebuild.

 

it is what is commonly refered to as the fuel screw around here. its located towards the back of the pump with a small cover hiding it but if you havent been playing with it it shouldent be your problem? , the more i think about it it couldent have wiggled loose because it has a small o-ring on it.but idk?

 

When your pump goes bad, does it show signs of slowing down of performance? Or do you wake up in the morning one day and it just won't start? The reason I'm asking is that it didn't show any signs prior. I just want to elliminate all other possibilities before having the pump rebuilt. Thanks. -Jeff

 

A wore out head and plunger will start to idle slow and even die out when hot, but there are several other problems you could have that just happen and that's all she wrote. Broken plunger return springs are one of those possibilities.

 

Thank you for your insight Dave,

I assume the thing needs to be completely removed to replace the plunger and return springs?

Please advise me on where I can get a rebuilt injector pump that will be a reputable reliable rebuild, and not break the bank too much. I think this is the way I will have to go.

Again, thank you and everyone here for all your helpful informaiton suggestions and ideas.

-Jeff

 

Yep, the pump has to come off.

Let us know approximately where you are and I'm sure somebody will have a recommendation.

 

I am The Big Island in Hawaii! 96738

Mahalo.

 

did u check the fuel shut off solenoid check it i cant remember if its a ground or power i think its power then jump it to 12v power to see if its bad