Can an Electric Lift Pump get weak, or do they just give up suddenly?

[gavio]

Hey Guys:

I am asking this over here on the 6.5 side since y'all have electric lift pumps. I changed out my old mechanical lift pump on my 6.2 NA van and have been using an electric lift pump for over a year - and it's been fine.

Currently having symptoms of strange surging/lagging and nasty bucking under certain low-load low speed conditions. I suspected my lift pump becasue at times I thought I didn't hear it working, but when I went to check it out, it was tickin' away just like usual. The symptoms came on very suddenly.

So, hence the question, can electric lift pumps become weak or eratic, or are they simply either working or not? Just trying to narrow down my choices, ya know.

Thanks for any help or other ideas.

[moondoggie]

Good Day!

Electric lift pumps, like anything else, can & will fail any way they want. Do they typically become intermittent? I hope others weigh in, I don't know.

In our 6.5 trucks, lift pump system failures are typically the oil pressure switch (which powers the lift pump except when cranking) contacts getting ohmic, or the lift pump itself fails.

Good Luck & Blessings!

Brian Johnson, #5044

[BUZZ]

What moondoggie said plus a lift pump can run but at reduced output as well.
Buzz

[triggerman]

The IP will draw up fuel on it's own to satisfy low speed requirments with a dead lift pump, as mine did. At idle, open the bleader on top of the filter, you should get a good stream of fuel comming out. If not ,the pump is probably bad. Does the engine rock in the mounts at hot idle? If so, your looking at a injector job. Or you may have a very badly stretched cam/IP chain giving you a radical timeing bounce. How many miles are on the engine?

[gavio]

It's got 160k miles on it. When I had it timed by a fellow member of the DP who has the timing meter, he said that it seemed pretty steady and that was only about 5k miles ago. Also, the injectors and IP are only a little older than that - maybe 8k miles or so - I'm sure hoping it isn't anything like that - if you've ever done those projects on a van, you'd understand my dread.

I'm going to check out teh lift pump some more and may just have to try replacing it and see what happens

Thanks for the feedback, folks. Anything else?

[rjwest]

Install a fuel pressure gage , eliminate the guess work. Plus it looks neat.

[morgan]

Mine got weak. It would just barely leak out when I was shorting out the fuse to refil the filter houseing after a filter change.

I replaced the lift pump, and it squirted like Old Faithful, and ran a lot better too. Wish I had realized the diminishing performance 4 years ago. I've lived with it too long, and didn't realize.

Good luck!