Engine/Transmission (1998.5 - 2002) Had FASS 2 years, no trouble till now

[SKargo]

I am intermittently getting 0 psi while running. The pump is not running all the time. I've tested it by bumping the starter, sometimes it runs, sometimes not.



Any thoughts on what to look for?

 

[ThrottleJockey]

Try replacing the motor's brushes.

 

[Cummins724]

Check for loose connections or corrosion on the terminals. The ground may be loose on the frame & losing contact.

 

[wcjp]

The guy I commute with has had two gauges go bad. The FASS continues to work great.

 

[SKargo]

I know the gauge is fine, as I couldn't hear the pump running when I cranked the key. As soon as I heard it running, the pressure came up on the gauge. I drove to work(3 miles) with no FASS today. I went to show a tech what was up, and of course, it worked.



If I can get it to not work, I'll put a test light on it and see if it's a wiring issue. If not, the pump is probably bad.

 

[steved]

I know the gauge is fine, as I couldn't hear the pump running when I cranked the key. As soon as I heard it running, the pressure came up on the gauge. I drove to work(3 miles) with no FASS today. I went to show a tech what was up, and of course, it worked.



If I can get it to not work, I'll put a test light on it and see if it's a wiring issue. If not, the pump is probably bad.

As these guys eluded to, it's probably a brush issues... might want to remove them and see what they look like... they are replaceable on the older FASS...



steved

 

[SKargo]

Steve,

what do good vs. bad brushes look like? I pulled the one from under the damaged "cover" and it looked fine, but I had nothing to reference it against.



Today I drove it to work with my gauge reading 0 psi. Only 3 miles so no sweat.

At lunchtime I tried to bump the starter and the pump works, of coure

I started the truck, and with the pump running, I unplugged the wiring harness. The truck started sputtering and getting ready to stall, so I plugged the pump back in, and I could feel the pump running.



Got in the cab and the gauge was reading 0

I pulled the connection off the isolator on the fuel filter housing and cleaned it off best I could with my knife.

Drove home for lunch, back to work and then home again with no issues and no reading(false or otherwise) of 0.



It's all good except I'm still stumped on why a few times when I bumped the starter, the pump didn't come on.

 

[steved]

There are two brushes... one might be hung while the other is fine...



Almost sounds like the guage is wacked out??



steved