2nd Gen Non-Engine/Transmission Fass Pump Failure?

[BMote]

Installed FASS pump 4 months ago. Running 16# pressure on guage consistently. Yesterday, cruising around, the pressure dropped to 4# and stayed there. Had full tank of fuel, don't know what is up. I checked 12v feed to pump fuse,ok, started truck and disconnected fass pump plug, had 12v there also, engine faltered, reconnected plug, engine picked up and pressure jumped to 16#. What's up here? Am I going to lose this pump sometime in the near future, probably in a very bad location (100 miles from nowhere), or was it just a gliche hiccup.

Anyone experienc this fault?



01 w250 auto, fass, amsoiled, 4" straight exhaust, 6"lift,brush guard

 

[JDKammin]

Isn't there filters on the FASS system? Have you changed them?

 

[VHolloway]

is it the fass II pump that has a small filter just before the pump just after the tank

the fass II pump is just the pump but it has a small pre filter

 

[BMote]

Fass is pump only system. No filter that I can see. Direct line from pump to tank.

 

[RTillery]

Are you running an isolator on your FP gage? Mine did the same thing as yours. I added a little more antifreeze to the cab side of the gage and it has been fine for a year now. I have about 50,000 on the pump so far. It has been flawless.

Good luck.

 

[BMote]

Yes, I do have an isolator on my guage, just topped up line antifreeze about a month ago. This would not appear to be a problem, as guage now is steady at 16# again.

 

[RAJohnson]

Verify gauge and or Isolator then Change FF. How old is your FASS pump? Have you replaced the brushes lately, you may have a brush problem, moisture could have gotten in there recently.

 

[BMote]

Fass pump is only 6 months old, should I have to look at brushes already? Is there a life on them, or what maint is req'd on these pumps? Is there a built in filter trap I don't know about?

 

[twopipes]

Did you bleed the line going from the FASS FP port to the guage isolator? I forgot to bleed mine and guage reading was wacky after about two months of constant 16 psi readings.

 

[steved]

There is a inline screen between the tank and FASS II pump... if this isn't there, you might have gotten dirt into the pump...



Does your pump motor have a silver end on it... if the end is black, then it is brushless.



Sounds like you got dirt in it.



steved

 

[RAJohnson]

Fass pump is only 6 months old, should I have to look at brushes already? Is there a life on them, or what maint is req'd on these pumps? Is there a built in filter trap I don't know about?

Nope I would not worry about the brushes if your only 6 months old. There life should be many years if kept clean and dry. I am not aware of any filter trap, I am assuming you are still using your OEM FF (fuel filter), have you changed it lately. Sounds like more of a gauge and or isolator problem.

 

[monkeyman]

I posted about a week ago about my faiure with my FASS Pump. I also sent you a PM

Rick

 

[BMote]

:{ :{ Pump failure again. This time back in bush about 10 miles. No amount of fooling around brought it back up. Drove home on really low pressure. Took pump off truck, no brushes in pump, cleaned small check ball and spring, no apparent dirt in pump housing, re-assemble, install, still not much pressure. Bled system at isolator, no change, firmly believe it is not an isolator/ guage problem. Enuff fuel in hair,eyes arms for today. I quit. Maybe tomorrow take pump off again and test in bucket to see if I can build pressure. Could be a restriction in tank,cutting off feed to pump.

 

[ROADWARRIOR]

Did you ever find your problem?

 

[LowFly]

Please, do tell...

 

[KenBr]

I too just got a FASS pump and had a pressure problem. However it really wasn't anything to do with Pump it was the sending unit in the tank that was causing a restriction so the Pump couldn't create the normal 16psi. Just my two cents. You may want to check that out.

 

[SSabick]

I still say isolator. My isolator failed within 8 months. Now I have an electric gauge, and I am considering the mechanical gauge again, because I am wondering how much fuel pressure I really have. My gauge stay's pegged at 15 psi. I will have to look into building one of the needle valve set ups I have seen in the past to bypass the isolator.

 

[LowFly]

I still say isolator. My isolator failed within 8 months. Now I have an electric gauge, and I am considering the mechanical gauge again, because I am wondering how much fuel pressure I really have. My gauge stay's pegged at 15 psi. I will have to look into building one of the needle valve set ups I have seen in the past to bypass the isolator.

This is what i run. I do need to get a snubber for it... ... but i can crank the valve down to its just cracked open to keep the gauge from rattling... ... I see way too many issuse with isolators... ...

 

[steved]

This is what i run. I do need to get a snubber for it... ... but i can crank the valve down to its just cracked open to keep the gauge from rattling... ... I see way too many issuse with isolators... ...

Not that it matters, but I run a liquid filled guage from Summit Racing... mounted inches from the CP3 inlet... I have never had an issue... it is mounted directly to the line... I am beginning to wonder if those guages you guys are running are any good...



steved

 

[OL RATLR]

This is what i run. I do need to get a snubber for it... ... but i can crank the valve down to its just cracked open to keep the gauge from rattling... ... I see way too many issuse with isolators... ...

Just run a mechanical gauge with needle valve mine has been on

4 yrs no problems. Oo.