lift pump failure

[LJolley]

What symptoms does the truck have if the lift pump has failed/and or is failing. I'm looking for help in diagnosing because my warranty is soon to be history, thanks

 

[Bigsaint]

Short of the obvious, guessing that you don't have a FP gauge hooked up, would be very sporadic FP readings that seem out of the norm for your pump. Mine would jump around from 12 psi's to 6 psi's at idle.



Without a gauge, how's the performance ? Before I had anything in the truck, besides an Edge EZ and the other gauges, my truck had a real bad stumble after a short but fast hill climb. I lost all power, had to pull off to the shoulder while the truck sputtered and spewed white smoke out of the tail pipe. After several minutes at a rough idle, all was well. When I had the truck at Auto Wurks, I asked them to check the FP and it was very low, seeing around 6 psi's at idle and 0 at WOT. That's when I replaced the Carter with a Mallory pump and added a FP gauge.



Another item is hard starts. From what I've heard, they will listen if you complain of hard starts and the FP is low. If you end up being out of warranty, don't sweat it. You can pick up another Carter pump ( buy it from Cummins, not DC !!!) or you can go the aftermarket route and place a pump back back the tank. Hope this helps !!!



Scott W.

 

[CumminsAholic]

Scott's right, hard starts. Change the fuel filter. No start=bad pump. I just checked a guy's and he never heard about weak lift pump's. He said he had changed his fuel filter and had to push it to start it. So I took off the top test port and had him turn on the key... nothing, not even a drop of fuel came out. Then we had to pull it to get it started again, he's pretty happy I mentioned it to him. His pump was totally dead. So you could loosen up a test port, or open up your "water drain valve" just a crack and bump the starter, if it pressurizes it and makes fuel squirt out you should be ok, at least it isn't totally dead. But, it could be like my pump was, on it's last legs. It would be really erratic, my gauge would bounce all over going down the road, again like Scott had mentioned. I replace mine and gained a solid 3psi from idle to WOT. Cheap insurance. The old one is now a spare. Also, mine became very noisy when it started to go out. I usually couldn't ever hear it run, but once it started to go it became very loud. When I would turn on the key to let the grid heater cycle it was very obvious that it was running. Hope that helped a little.

Corey

 

[Un-Hemi]

Hard starting isn't the only symptom of a bad lift pump. My truck usually starts on the third compression. It runs normally at anything under WOT. On a recent trip, at WOT travelling up a grade, locked up in OD, it wouldn't rev above 2600rpm. When towing 6000lbs up a moderate grade in 3rd, the engine hesitated, snapped and popped. Recently I measured the lift pump pressure and it was low, going to 0psi as fuel demand increased. It also wouldn't fill the filter cannister after a filter change. You'd think it would either work or not. It just ain't so! It can be just marginal!



New lift pump, Ray's banjos and VDO fuel pressure gauge to be installed while the truck is hibernating over the winter.

 

[Briar Hopper]

LJolley, I'll be in Muncie, Indiana next Friday Nov. 30, if you want to meet up with me. I have a portable fuel pressure test gauge that screws right onto the test port fittings of our 2001 trucks, with the hose being long enough to lay the gauge on the windshield and tape it in place. Only good way to test the pressure is under hard acceleration, i. e. , W. O. T. (wide open throttle). No charge to help ya out, of course. If you feel like it, you can make your own gauge , especially if you can't spare the time to meet me in Muncie. Just email me, or send a PM , I'll give you details.