Engine/Transmission (1998.5 - 2002) Help Guys,still have low lift pressure.

[BGoodale]

A few months ago I asked for a friend about some fuel pump lift problems that he was having. Here's the scoop; a 1998. 5 one ton all stock . About 180,000 miles and somewhat abused by previous owner. hE had lift pressure problems with the original pump . I helped him get home with the replacement pump and then we did the Genos relo kit to the outside the tank pressure pump . All was fine for a short time then the pressure started to drop on the next trip so we then did a fass ddrp pump that was not up to snuff and was replaced by Genos. Then the new pump went south within a 1000 miles. We sent the pump in to be tested and was fine. The advice from Genos was that the tank must have a bunch of junk in it that is being sucked up into the intake tube and reducing pressure. So we dropped the tank and except ofr the sliding mechanism being worn there was no crap in the tank and every thing looked fine. Bummer. So the latest is that when he fills up and has to pull hard for awhile the pressure can fall to 1 to 2 psi. As the fuel level falls the pressure rises to 10 to 12 psi at idle and 8psi on a hard pull. He does have a fuel gauge. I can't figure it out but he is coming over monday am . Should I blow out the all the lines or what. Thanks for your help and sorry for the wordiness. Brett ps. when the pressure drops to the 1 to 2 psi he'll pull over and shut the engine off and then pressure is upto 8 to 10 psi .

 

[turbo torque]

might want to check voltage at pump when pressure is low... GOOD luck

 

[Joe Mc]

Is the tank vent clogged? When the psi is running low see if there's a hissssss when loosening the fuel cap. Have him watch the psi gage as you're loosening the cap.

 

[rMetzger]

Is the tank vent clogged? When the psi is running low see if there's a hissssss when loosening the fuel cap. Have him watch the psi gage as you're loosening the cap.

Seems like I saw a whole thread, either here, @ dieselBOMBers.net, or somewhere that mentioned A BUNCH of trucks leaving the factory with the tank vent still enclosed in the wrapping plastic that the parts vendor sent'em to Chrysler in

 

[barryg41]

On a trip back from Nashville, I stoped just south of Memphis for diesel. As soon as I got back on the road the fuel pressure started to drop. Went all the way to zero. I was pulling a trailer that weighted about 7k, as soon as hitting 0psi, it started to stumble. Pulled over to the side of the road checked things out. No problems that I could see. Then It died, started it back up. It took about five seconds to catch on but the fuel pressure was back up to around 13lbs. So I drove on and slowly the pressure would drop off. Stopped and started the engine again, the pressure was up to 15lbs. Did this three more times till I got to Baton Rouge. Bad fuel of course. I checked the inline filter, it was clean and the OEM filter was clean. I changed both out though.



I went and bought a quart of Power Service Biocide Fuel treatment. Two tanks later all was good since then. This stuff is expensive, $25 a quart, but works.



Could he be buying BAD fuel? Or from a fuel station that does not treat their underground tanks?

 

[BGoodale]

Thanks guys for your help. To Joe Mc eventhough we had his tank down earlier I did nnot notice a vent but there has to be one or is the cap vented? We may have to drop the fuel tank again to see if the vent is there and possiby clogged. He has gotten fuel in several locations and summer and winter times so I don't think the fuel is the problem. Any other ideas and maybe where the vent is. Thanks . Brett

 

[Dieseldemon]

The vent is in the cap also check the overflow valve in the inj pump.