i've got a 99 3500. have had a rough idle and low rpm miss for a long time. bought the truck w/90k. has had problem since i bought it. first diesel nothing to compare it to. finally took it to cummins. diagnoses was low pressure from lift pump. replaced pump. problem continues. back to cummins - &quot;pop&quot; tested injectors. all are bad but one. truck has 117k miles??? technician says he believes my injector pump is going bad. talked to local turbo/injector specialist. he said inj. pump may be trashing injectors or i may have fungus in fuel system causing early injector failure. any ideas??? <br><br>also if replacing injectors, should i buy &quot;275 hp&quot; injectors?? what are the pros and cons??

 

If you have documentation from dealer about fuel pressure problems you might be able to get inj. pump- injectors replaced under warranty. Key word here-DOCUMENTATION.<br><br>Guessing I would say that your injector pump was damaged when you bought it thus causing injector problem ???

 

No &quot;proof&quot; of inj. pump problem, only lift pump, 3 psi at open throttle. cummins says they can't test injector pump. truck runs fine going down the road, just rough idle and low rpm miss. always that bad fuel pump meant no power.

 

I follow ya, replaced lp after 100k. Can you prove that there was a problem before 100k thru documentation. Well even if you could I doubt a dealer even a good willing to work with ya kinda dealer wouldn't warranty anything. Might be able to call DC direct.<br><br>A cummins shop can bench test the the vp 44 if they have the equipment. I would try to find one and get it tested. Yep, from what I understand bench test only.<br><br>If you only have 3 psi wot right now I would be sure to put on another lp.<br><br>Somebody else with more knowledge otta get in here to help out.

 

Drive a truck with a bad lift pump long enough it can kill the injection pump.<br><br>Paul

 

[quote author=firedawg link=board=13;threadid=10331;start=0#98992 date=1044056227]<br>No &quot;proof&quot; of inj. pump problem, only lift pump, 3 psi at open throttle. cummins says they can't test injector pump. truck runs fine going down the road, just rough idle and low rpm miss. always that bad fuel pump meant no power.<br>[/quote]<br><br>If Cummins cant test the pump, it will be the first Cummins branch that I ever heard of that couldnt. Cummins uses a little black box that plugs straight into the VP44 and attaches to a 12v source. However, this may be only used for trucks that will not run at all. But, they do have them. Have they tested for a possible restriction in the fuel supply line? What about troublshooting the main connector on the back of the VP? Have they checked the Crankshaft Position Sensor? Camshaft sensor? These pumps are not very hard to troublshoot if you have the schematic from the manual, #7 pin is 12v supply, #6 is the datalink from the ECM. What codes, if any is it throwing?