NEED SOME OPINIONS, GUYS AND GALS. tHE OTHER DAY WHEN I STARTED THE TRUCK UP TH FUEL PRESSURE ONLY CAM UP TO ABOUT 8 POUNDS, (NORMALLY HOLDS 17 LBS.) AFTER DRIVE A FEW MILES I NOTICED THAT THE PRESSURE WAS FALLING SLOWLY. BY THE TIME I GOT TO WORK IT WAS AT 0. NOW IF I SHUT THE ENGINE OFF FOR A FEW MINUTES AND RESTART IT, THE PRESSURE RISES AGAIN, USUALLY TO 5-8 LBS, THENS STARTS DROPPING AGAIN. SOMETIMES IT WIT GO TO 17 LBS AND ACT NORMALLY. I ALSO NOTICED THAT THE GUAGE DOESN'T FLUCUATE ANY WHEN IT IS RUNNING LOW WHEN I HAMMER IT.

DO YOU THINK MY GUAGE MAY BE GOING BAD, OR THE LP.

ANY HELP WOULD BE APPRECIATED

THANKS,

ATCH

 

Sure could use some help

 

Have you tried changing the filters? If not I would think the pump maybe going bad.

 

hook up a test guage and see if it reads the same as your other guage.

 

I bet you're using an isolator for the gauge, right?


Sounds like it's the sender or the gauge...

 

do you have a good ground for the gauge?

 

Yes, I'm using a diapram type isolator with a mechanical guage

 

I like fewer "kinks" in the plumbing... more reliability IMO:

 

Check your fuel supply lines. Just about under the drivers seat and on the inside of the frame there is a junction between the steel line from the tank and the rubber line to the transfer pump. Mine was very loose and sucking air. couple of small hose clamps fixed the problem. Been good for over a year
Bob H

 

Already did away with the metal lines. I have 3/8 rubber lines running up to the filter. I wonder if I could use an old oil pressure guage for a test guage?

Atch

 

You can use any type pf pressure guage for a test guage. Bypass the isolator and see what the test guage reads.

 

I agree with the Good Dr. Evil... I would grab any kind of pressure gauge and retest the fuel pressure. Like a 0-30 PSI works great... Even if you have to take a boost gauge (0-35 PSI) and use it...

 

its the lift pump just had the same thing happen to mine we fassed it and now a solid 17 psi

 

Could be the Fuel filter is begining to clog?
robie

 

my truck did this just the other day...i already have an aftermarket transfer pump so i went straight to the guage. it was my isolater sticking. now it works great again just like before..