DL1221

When I pushed the prime button, the lift pump started to leak fuel. It was just a few drops and it only leaked when I pushed the prime button. Fuel pressure is OK, 25psi at idle, and 32psi at 2500 RPM (no load). Should I replace the pump, or is this normal? Thanks for any help.

infidel

The only replaceable part on the lift pump is the o-ring that seals the primer button. Best to remove the pump to replace it.
If I were to go that far I'd be tempted to replace the pump and keep the old one for a spare.

Baja

If you do remove the lift pump, replace the bolts with studs. It will make installation MUCH easier.

waldersha

I just came looking for the same info. I saw a few drops on mine today when I used the primer button. Could that button leaking also be leaking air back into the system?

I was messing with the starwheel yesterday and today I went to start it up and ran rough for 20-30 seconds then died. Had to prime to start. This has happened everytime I have messed with the starwheel, but I don't quite understand why??? There is definately air getting in the system, but I don't see why this would set it off. I have replaced the lines all the way to the tank, checked the tank module and replaced the overflow valve, so I think the lift pump is the only thing left.

Any ideas?

waldersha

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DL1221

Even though my lift pump was leaking when I used the primer button, it was not allowing air to get into the system. The truck has always started OK, in fact, the lift pump even has good fuel pressure. However, I am going to take Infidel’s advice and just replace it, instead of waiting for the rest of the pump to go bad ($175 from Cummins, but I’ve seen much cheaper from the aftermarket). Since you’ve replaced everything else, I’d say there’s a good chance it is your pump that’s causing your air leak, I would just change it out, especially since its leaking fuel anyway. By the way, did you use high quality, diesel rated fuel hose? I’ve read here that cheap gasser hose will deteriorate and cause air leaks. Just my 2-cents of advice, hope it helps. . .