Cummins dying

K.Daddy1 · Apr 28, 2011

I got a 6 cyl cummins in a pettibone fork lift, that has sat most of the winter. I noticed when I pulled it out of the barn, it just didn't feel like it had the power that it should have. I had to give it more than normal pedal to make her go.
Went to town, got all new filters, fuel and air, bleed the system ran just fine I thought. After about 5 minutes of idle running, it will up and die. It will crank over a few more revolutions before it will start, but once it starts, it idles fine. Go to give her some pedal to make it move, as soon as you let off the pedal, it will die. I've cracked open all the injectors, bleed it again, but no change. It still acts like its weak, just don't have the go to it like it should. Is this a sign the injection pump is weak?

kyhayman · Apr 28, 2011

Sounds like a lift or transfer pump to me. If it is, it can rapidly lead to an injection pump failure. Depending on which engine and which injection pump it has.

offand gone · Apr 28, 2011

If it were me I would pull the plug on the bottom of the tank and see if you get water or fuel with trash in it. If you do try another filter after draining the water out.
Frank

Nick Martin · Apr 28, 2011

If it has an electric fuel shut off silinoid, is it possible it could be sticking? I had a 97 dodge truck with a cummins in it that wouldn't start at all after sitting a few months. So I lightly tapped and then pulled on the little shaft and she fired right up. Lift pumps for those are not expensive if its a mechanical one, so they might not be a bad place to start. I had a john deere tractor that did something similar because someone took the fuel cap off and put a bunch of dirt, corn stalks, etc in the tank and it partially plugged the fuel line. I'm just trying to give you some cheap things to check before you go blowing $1000 on an injection pump.

K.Daddy1 · Apr 28, 2011

I know it doesn't have trash or water in the tank. It was drain and cleaned last summer, just as a preventive measure. I didn't think about the solenoid, but I will check that. Is there a way to check the lift pump by check pressure out put or something? I prefer a cheap common sense fix if possible, so I say Thank You in advance for everyones input. Thank You

kyhayman · Apr 28, 2011

The only lift pump spec I know for sure is 10 psi minimum on a 24v 5.9 Cummins with a VP44 injection pump. 9.4 psi is not enough, it takes down the injection pump, I'm guessing you know how I know this. Best of luck chasing it down.

twopop · Apr 28, 2011

what model cummins and what year,makes a differance

JOHNNYfromMI · Apr 28, 2011

If it's a older motor with a manual over ride for the shut off try turning it out.

petetx · Apr 28, 2011

simple thigs first check and make sure the intake is not plugged had it happen to me it wouldn't come up to power

Tony in Mass. · Apr 28, 2011

How old are the filters?

Anonymous-0 · Apr 29, 2011

There is a screen in the inlet side of the lift pump that was plugged in my cummins.

HTH
peter

Dodgeit · Apr 29, 2011

My wifes '84 Mercedes diesel had a similar problem, about a year ago.
turned out that the new biodiesel she was putting in the tank was killing the algie that had accumulated over the years in the tank. Had to change filters a number of times before it cleared up.

K.Daddy1 · Apr 29, 2011

Checked a few things out last night. Found the lift pump is putting out around 7.5-8 psi. Going to order a new one this afternoon. Thanks for everyones input!

Dblair · Apr 29, 2011

if it's a p-pump it will have a return line check valve on the side of the pump opposite the linkage very near the valve cover . the spring in the valve gets weak and doesn't retain the fuel pressure in the pump . stretch the spring a half the length and the engine won't die. it is a banjo bolt with a check built in the top half of the bolt. don't lose the bolts washers top and bottom of the fitting.

Cummins dying

K.Daddy1

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offand gone

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Nick Martin

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