Engine/Transmission (1998.5 - 2002) FASS titanium pressure adjustment?

[VolsFan]

Been running this for a few weeks or so, pressure been between 15-20 until today, been at 15 and pulled it down to 10. Any ideas? Saw there is a slight drip at either the feed or return line, instructions said not to put pipe dope on them just Teflon , which I always do both. At some point gonna take them apart and dope em, but truck starts up fine and runs good. Thanks

 

[JR]

If your confident in the accuracy of your gauge then the spring and ball in the return line going back to the fuel tank are the likely culprit. You have to remove the fuel line then unscrew the fitting from the pump and the ball and spring will be in there. I've seen the ball lodge in the spring which will cause a drop in pressure, but this has typically been on pumps with some run time and the spring was worn.

 

[VolsFan]

JR, thanks. I stretched the spring a little on the return. When I run the truck at idle it hovers at 5 psi now. When I crank the starter to activate pump it runs at 20 psi. Have no idea what's going on. Don't have a manual pressure gauge, the isspro electric detected the lift pump that just died on me, still can't rule it out. Little scared to run it now, probably five genos and/or FASS a ring tmrw

 

[JR]

Something else you could verify.

http://dieseliq.com/check-replace-fuel-return-overflow-valve

 

[VolsFan]

Got some good troubleshooting tips from genos, gonna do the bucket test to ensure the pump is ok which I'm sure it is, kinda leaning towards the electric fuel pressure gauge. I have a snubber valve coming of a 90 on the injection pump, what's best way to make sure this isspro electric gauge is reading accurate? When I bump starter it'll run and hold 20 psi but when truck was running only was holding 5 at idle. Not gonna be able to get to truck til Friday to fool with it. Got a walk through on getting a mechanical reading too which may be best way to find out(got trucked towed several weeks ago by a 1st gen 91.5 2wd when the airdog died,really liking the idea of driving a cool old 12 valve sometimes!)

 

[GReed]

If you still have the original fuel lines on the engine, you can hook up a mechanical gauge to the factory schraeder valve. Genos have test gauges.