I have a completely stock 1999 dodge ram 24v. first question is, I replaced the lift pump with a new carter mounted below the filter. At idle I am only getting 10psi, at a steady 50mph I get 7psi and just touching the pedal I drop to 2psi. Is the new pump bad? Second question would be, all the new sending units seem to come with a pump for in the tank, as this isn't used in the diesel should I take this pump out? Someone has replaced this sending unit before and they did remove the pump. Could I just wire this pump to a switched wire so it would help feed the lift pump or is my whole problem just a new lift pump that doesn't have enough guts.

 

I don't understand all of this, but I would advise you to put the truck back to stock setup. That is what they were designed to run with. An external pump mounted outside the fuel tank won't deliver the proper amount of fuel pressue.

 

ok, let me go with one problem/question at a time. 1999 ram 24v cummins completely stock did not have a fuel pump in the tank. It only had the fuel/lift pump mounted on the engine block. The connector at the sending unit only has power to the 2 lines for the gauge, the 2 lines that would power the in tank fuel pump are dead/not used on a diesel. You can convert to an in tank pump but the ECM needs to be programmed at the dealer to energize the connection at the tank. I can only find a replacement sending unit that has the pump so I am guessing that they make these generic between gas and diesel. My question would be, do I just leave the pump in the sending unit or take it out?