Engine/Transmission (1998.5 - 2002) Fuel presser

[Truckie]

Well I don't know what to do now so I'm asking for some help. I had a new lift pump put on at the Dodge dealer bout 3 weeks ago and all was fine, Then I put a whole set of gags in truck that included pyro, boost, and fuel. When the gage was hooked up the psi was low with new pump it idled around 7 psi, going down the road it was @ 5 psi. Now shut the truck off and then restart-it and get a whole new set of fuel readings like around 10 psi at idle and going down the road it was 7 psi, I also had the Edge comp put on. So i went to Cummins and bought a new lift pump put it on and get the same readings what is up with that.

All the gags are Isspro and the fuel presser is also Isspro with an isolator. Any help I just spent $ 140. 00 on new lift pump and get same readings.

Thanks

Mike

 

[Sticks]

What kind of fuel pressure gauge is it?

 

[Truckie]

All the gags are Isspro the fuel presser is a Isspro with an idolater.

 

[Car_nut57]

Depending on the isolator air trapped between the gauge and isolator can cause the isolator to bottom out and give a false low reading. This one possibilty for the gauge reading being incorrect.