Today i put gauges in a 2002 dodge 2500 all the other gauges work fine except the fuel. I bleed the isolator the pressure was running about10-15 psi. I was as happy as a clam intill i drove it. when i stand on it hard it drops below 5 psi and it does not come back up.if you shut it off and start it back up the fuel pressure will be normal again intil you stand on it.I am not shure whats wrong. Please help i think the fuel line going to the isolator might be to long. Somebody throw me a freakin bone

 

Not sure you are having problems with gauge are lift pump if you are pulling
it down to 5psi.Hook it up with out isolator and see what it does.
I am running mechanical Fuel pressure no isolator . No problems 4 yrs

 

Thats usually what guys say when they put a fuel pressure guage on for the first time.

You instictivly think it is the guage but all along the LP was in fail mode.

A lot of guys find out that there is no pressure when they install a fuel guage.

Remember the Injection pump will pull its own fuel, the Lift pump primes it and keeps it cool with fuel.

So conceivably, the LP could be dead, but as long as the IP is still primed it will continue to run.

But not for long

...................Jim

 

I had to prime my line from the isolator to the guage three times before I believed it. In that time I thought the LP was bad and swapped it. Now I keep that one for a spare.

Chris