noisy/surging fass pump

[moolie]

Ok well after wondering why the hell my fass was so loud and speaking to brad a few times he had me convinced it's a restriction in the tank. I had spoken to lazer bob a few times wondering why it was so loud and we weren't exactly sure if it was supposed to be that way or not. Anyway i must say that the surge was causing less than desirable effects to my turbo and it seemed to bark all the time (at least 30 times a day) I mean it was ridiculous. I asked bob what he thought and he went ahead and plumbed a new fitting into the tank and now the truck runs great, I can bearly hear the fass pump at all even with the window down, and the turbo hardly ever barks maybe 2 times or 3 times a day. So if there is anyone wondering about that loud fass, this is one way to fix it and it's a whole lot better.

thanks again to lazer bob, the only mechanic that i let touch this rig.

 

[JBlock]

I wonder it the whole problem with lift pumps might be the poor fuel tank pentaration you mention causing your noise FASS.



Like trying to suck fuel threw a straw.

 

[R D Brown]

I did not have a loud FASS pump but I did have the engine stop running, (three times) when the tank still had about ten gallons. I replaced the tank fuel module with a home built one and no more problems. I feel the FASS was removing the fuel from the module faster than it could be replaced, just enough to suck some air. After the modification was complete and the bed was still up in the air, I got right next to the FASS with the engine running and I could not hear any pump noise. The flow for the FASS is around 1. 5 gpm and I think the flow for the original pump is somewhat lower.



RD Brown

Anacortes, WA

 

[mhenon]

I wonder it the whole problem with lift pumps might be the poor fuel tank pentaration you mention causing your noise FASS.



Like trying to suck fuel threw a straw.

"BINGO"... . I'm still betting there's more to this then "just" the LP.

There's a thread going on at Fred's TDI (the VW site) about an early fuel module in the VW's. Some of the guys ended up drilling the gut's out of this fuel unit. . and the problems stopped (icing and plugging at the fuel inlet). Everyone remarked on this "syrup through a straw effect" caused by a restrictive inlet. Didn't take anything to gum up the works.

The VW, by the way, has a similar injector pump as our VP44 (it's a Bosch) and "no" LP. It draws it's own! Hmmm!

Mike

 

[tractorface]

I am certain that the tank module is the problem!

I am convinced that the fuel tank module is the problem. The new fangled high flow FASS just brougt it to the surface. I also don't think the quality of all the modules is the same and that is why some LP's last and some do not. I'll let you know how nice my FASS and VP feel after a couple hundred tousand miles running wih my custom tank module



I would like to see the reults fom a truck with a stock LP and a custom pickup tube. Just ask the guys that were bave enough to tap the bottom of the tank.



If you are on the fence try this. Remove the feed fom the VP and watch he fuel flow pulse while jumpeing out the LP, now remove the suction line from the tank and let it suck directly out of a bucket with no DC restricto module inside. The pulse will be gone, problem found

Seee Ya :-laf