Making sure it's the fuel pump

02SteelBlue

TJ Enthusiast
Original poster
Joined
Jan 29, 2019
Messages
412
Location
New Orleans, La
2002 X 4.0

I have the long crank. Before I get a new fuel pump assembly and go through the potential headache, I'd like to verify that it is actually the pump.

I have tried turning the key on and off several times to prime the pump (is it primed when the gas guage kicks on?) then start it. It still has the long crank.

I bought a fuel psi reader from Harbor freight. The pressure goes up to 49 with the key in the on position then begins to drop.

Are there other things I should be looking in to?

Like I said, I'm just wanting to verify that my problem is the pump. I thought priming it would help narrow it down, but it just raised more questions.

Thanks!
 
Since the pressure drops nearly as soon as the key is turned off that sounds more like the fuel pressure regulator. As in if you get a slow start after the engine has only been off a short while, like getting gas or running into the store that sounds like the FPR. When it takes longer for the problem to occur, like several hours or overnight, that is more likely caused by the fuel pump.