uberplasma

Hi everyone, newbie here, first post!!
2 parts to the question:

I have the 5.9l H.O. Cummins in this puppy, flawless performance until the other day when got some hesitation in accelerating up a hill, choked and coughed a bit, but kept going. I got home and replaced fuel filter and air filter as it was in the red. The engine would not start. After the filter was replaced, the bowl did not fill on its own, should the pump fill the bowl on its own? I eventually poured sone diesel into the bowl and started fine.

truck went along fine until yesterday it started doing the choking and coughing after coming off turbo on the highway, even stalled out on me. Was only 2 kilometers from a dealer so drove it there and they were too busy to look at it. So i key danced the following codes: P0628, P0514, P0483, P0480. Drove it home from the dealer(they were too busy to even tell me what the codes meant) Power washed everywhere and cleared all the dirt and salt from everywhere and the P 480 & 483 cleared all by them selves. The 514 does apply to me as I use the block heater almost daily and I know this one from my Caliber as it had the same non life threatening code for years until I had the memory updated. But the P0628 was still there. I checked wiring for corrossion or shorts and checked voltages at the pump, everything checks out, 1 battery is a bit less powerful than the other, but I can't simulate the speed or RPM's of when it fails. Given this and the first problem does this sound like the fuel pump, any ideas or further ways to test more possibilities would be appreciated.
Cheers
Dave

papaduck

Welcome to the forum.

The lift pump will run for about 1 second when the ignition switch is turn on. To get it to run longer you need to bump the starter and then the pump will run for about 25 seconds. I do this twice when I change the filter to purge the air out of the lines.

It does sound like the lift pump may have failed. The CP3 can pull the fuel and that maybe what happened when you poured fuel into the filter. This could also be why the engine was stalling when the extra demand required more fuel. A fuel pressure gauge is the best way to test the pump but a flow test is easily done by putting a cantainer on the filter drain hose, open the drain valve then bump the starter. You should get more than a quart of fuel. If not then the pump is weak.

If you still have the pump on the filter canister then it is very prone to fail and should be replaced. If it has been replaced and in the tank, I would go with an after market pump that is outside the tank such as the Air Dog or FASS.

uberplasma

Hi papaduck
Thanks for the info, I was going to try the bump test this morning. I had pretty much narrowed down the pump as the culprit, but your post has helped me seal the decision to go with the aftermarket assembly, died on the highway luckily was not that busy but as summer comes I will have the 5th wheel on and do not need this happening under load. Thanks again for your post. Will swap out and update later in the week.
Cheers

SOhappy

What papaduck said is right on. My '03 left me stranded by the side of the road when it's block-mounted pump failed at 75k. Dealer installed the in-tank unit under warranty. It was expected, as this is a known issue.

By the way, don't ever pour diesel in the fuel filter canister- it goes straight from there to the injectors..unfiltered.

uberplasma

good to know - oops! thanks for the heads up, was looking at the injector pump $2100 from dealer or 950 from rockauto, injector 400 each, the truck is off the road until the pump comes.
Thx SOhappy

NJMurvin

Or you could consider replacing the OEM pump with a replacement from Geno's for about $160.

SOhappy

Just to be clear, your "injector pump" is most likely not the culprit, rather your lift pump (low pressure pump that lifts the fuel from the tank to the fuel filter canister). It's only $75-$150 if I remember correctly, depending on which kind you get.

uberplasma

Hi
yes I ordered a lift pump, 150 delivered to my remote location in northern ontario, so a lot better than running the truck and risking the other pump failing
Thx
Dave

uberplasma

Hi everyone
so the pump came today, installed it and bam - key in ignition to heat the plugs, pump kicked in(never heard that sound before- wonder how long i was driving with the bad pump?)fuel bowl filled without even bumping the starter - started like the day I bought it - and now runs better no hesitation - turbo kicks in and lets go without any problem and the error codes cleared themselves. Thanks for all the help and info on the problem. now my omly concern is if I may have cut the lifespan of the injector pump short by running with the bad lift pump
Cheers

SOhappy

Congrats on the successful repair, that's gotta' be a good feeling .

jhenson

More than likely the CP3 is fine......they are designed to pull fuel to an extent....the Duramax's (older one's at least) don't have a lift pump and their CP3's are basically the same design as ours. I think you'll be fine....glad to hear you got it going.