My dad has a 02 6spd, third injection pump and second lift pump. He has a fuel pressure gauge and it has been acting funny lately. When he starts the truck he will only have about 4 or 5 psi. He will drive it for a while and then he will stop and shut the truck off for about 5-10 minutes and then when he starts it back up, it will run at 14psi for the next 200 hundred miles or so or how ever long he runs the truck. Could his lift pump be going bad, It has not been that cold lately, 20s and 30s so i dont think the fuel is gelling at all. Any ideas? Thanks for the help

 

If it's been through that many VP's and LP's, I think I would go with an after market FP and larger fuel lines.

I have the FASS II, but there are several options out there. Do a quick search for "fuel pump" and you will find a lot of info.

Good Luck.............

 

I have a new Cummins lift pump with jumper Still in box $115 Shipped.

Check battery voltage at lift pump. Remember when cold engine grid heaters are working. Less volts at lift pump

 

You could put that in the Classifieds, it would be easier.

 

I am now a believer that the original lines and banjo bolts are HIGHLY restrictive. R&Ring those, alone, would probably add subsatntial life to the VP and stock lift pump. Gotta be the cheapest, simplest, most bang for buck bomb there is.

 

I have the F.A.S.S on my truck and the lowest i see is 19psi on a cold morning start with the grid heater kicking on and off all the time. Any other suggestions? I told him to just ditch the factory lift pump and go with the FASS before his Vp craps out and this time it wont be covered under warrenty, already has 120000 on the truck

 

Just for giggles, pull and clean the battery terminals.
My pressures were fluctuating last weekend.
Pulled the battery terminals, they were pretty dirty.
Cleaned & resecured terminals, rock solid 16 psi at idle again.