I just hooked up my FP gauge, start truck and get 12-16 ,take it to Lowes pretty much 15 all the way there. On the way home notice I'm down to 5 at idle and 2-3 on accelleration. While my pump could coincidentally be dieing, whats the chances (40k on 2002), whenI finally get my gauge hooked up. It's an Isspro direct from the bottom of the filter housing with a valve to limit pulsing. Restarted when I got home, builds to 15 and drops to 5 again. Any thoughts?

 

this may be teh way it is supposed to be.What does the book say. I have worked on many diesel's in equipment that only had gravity feed to the injection pump. I believe that all the low pressure pump has to do is ensure that there is fuel to the injection pump.

 

I don't think so, my understanding is that the lift pump feeds, lubricates and cools the injection pump. Without adequate pressure non of these things happen and it kills your injection pump $$$$! Thats why so many Cummins guysadd the gauges. I'm just wondering if there was a possibility of a problem with the gauge or install?

 

OK, I start it this morning, FP climbs right up to 15, let it idle, back out of the driveway and park behind the Mrs.'s truck and then all of asudden the pressure just drops like a stone to 3. I'm thinking its got to be the gauge or? Any suggestions on things to check?

 

Try another gauge. I've got a generic hand held fuel pressure gauge I bought at the local parts store for $25. If the second gauge also shows a drop in, then I'd say you have lift pump problems. When mine died, it would work for a little while, then quit all together, let it sit on the side of the road, and it would start back up again.