With key in "On" position gauge needle strikes @ 50 psi for a moment then bleeds down to 40 psi. At idle needle flutters between what looks like 49-50 psi? Even took gauge off of air filter housing to ensure that it was not engine vibration causing needle flutter. Pressure bled down to @ 42 psi after I shut engine off & held for about 10 minutes. Additionally, while performing a volume test I collected about 3.5 ounces of fuel over 15 seconds or .233 ounces per second. Don't know what it is designed to be. The engine had been run about one & a half hours earlier for about 12 miles. Is this much needle flutter normal? Fuel pressure gauge is brand new so hopefully, it's not faulty. Also, I reran test and saw same flutter.

FWIW...'96, 4.0L, ax-15

Could this mean bad fuel regulator or leak in lines? Or just bad test procedure or no worries...just chill-ax?

 

not particularly sure i see a problem.

 

Thanks for reply. I am not sure there is a problem, but I thought that the needle flutter, as well as the pressure bleed down during the key "on" test, were indications of leaks or pressure irregularities.

 

You should maintain 49 +/- 5 psi for 10 minutes once the pump is energized.

Your check valve is failing.

 

Thanks, will have to investigate. I figure after 15+ years something has to give.

 

Does anyone think that the fuel volume rate, (see original post), could indicate obstructed fuel filter?

 

FWIW: I re-ran the pressure test with a different gauge, same manufacturer, and got similar results.