dodgediesel

I have a FASS 95/150 with the pick up tube installed. My fuel pressure gauge bounces back and forth from 11-13 psi, it's quite annoying! I just had my HRVP 44 rebuilt and he said there was extensive damage from cavitation??? I thought the FASS got rid of the air?? I noticed my FASS will surge at an idle. I tried the 5 gallon bucket thing and no difference. All fittings are tight and I've replaced one FASS motor already. Whats gives???

dodgediesel

I need Dan The Man to reply to this one!!!

bullboy85

im not Dan The Man but it sounds to me like there might be a whole or something in the line before the fass, that would suck in more air then the fass could get rid of and cause the pruesur to jump around from the air pockets

dodgediesel

Checked all connection, all tight???

bullboy85

i was thinking more of a hole in the line or something, did u silicon the conection form the pick up tube and the fitting to the seal?

dodgediesel

Sure did?? That's why I'm baffled!!!

bullboy85

well thats what it sounded like, i wonder if theres somethen on the fass unit thats leaking air in? im racking my brain for a way to even test to make sure it is air... this ones got me stumped

dodgediesel

Thanks for trying to help, I appreciate it.I thought Dan would chime in but I guess that's not going to happen any time soon???

Diesel-Dan

What do you mean by bouncing? The VP-44 is heck on gauges from feedback in the pressure line. If you don’t snub the pressure spikes that your gauge is seeing, you will get a Buzzing/Rattle effect. Mine did it, hence the needle valve I had to install.

How long was the FASS on the truck with the HRVP?

If you had fuel pressure, you were not running out of fuel. As for the air in the fuel, if our system was hooked up properly, it would be imposable for it to send any aerated fuel to the engine.

What i might suggest to you is install section of clear line between the FASS and the VP and look for any air. I really dont know what else to suggest as you got fuel pressuer and seems to be normal in operation.

We are not a cure for VP failures, but rather a solution to extend the life of the pump by feeding it clean fuel and keeping pressure to the pump.

Without seeing your old VP parts and how they failed...I don't know what else to tell you on this.

The FASS will make noise when running. What you call a surging, it sounds like normal operation. What happens is air builds up in the water separator. Once it overcomes the bottom of the boss that the separator screws on to, the air bubble gets sucked through the Gerotor in the pump. This makes a Whooshing/gurgling sound. And its intermittent. About every 5-10 seconds or so. The frequency might increase with more driving as the fuel will slosh more and become more aerated. NOW excessive noise along these lines and a loud pump operation will show extreme fuel restriction on the suction side of the pump. Pinch off the suction line slowly when the pump is running and listen to the pump and you will see what I mean.

Let me know if that helps.....

dodgediesel

Dan, thanks for chiming in, I thought you give up on us. I have a snubber in line and a 1/4 turn valve. Nothing is helping here. I have even changer out the gauge and sending unit, still the same. I replaced the motor on the FASS once and I'm guessing the irratic sounds this pump is making, is the air that's causing my gauge bounce all over the place? Replaced the filters and removed the line to the HRVP 44. Pumped the fuel out for a few minutes, bubbly fuel coming out. I put it all back together and the gauge is steady. Take it for a 2 minute drive and back comes the bouncing needle from 13-16 psi. Yesterday the fuel pressure was at 18 psi?? Today it's at 13 like it usually is. It's like there's something stuck in the unit??? Is it maybe because it's the 150 gal??

Diesel-Dan

MAN......it should be very hard for our system to have pressure creep like that. I dont like electric gauges because of this...they dont do well with VP-44's from what i have seen. I like mechanicals...and i would suggest double checking with one to confirm the readings you are getting.

You cant judge the amt of air in the line at full, unrestricted, flow....its going to foam up due to friction from the line and the fitting at the end of the hose. Not to mention you have 0 PSI in the line as well. You're engine will never use the total amt of volume our pumps put out. This is why you have pressure and can maintain pressure. You need to check when a clear hose at normal system pressure to look for any air.

AND ill be honest....any air that would cause cavitation damage (Usually a form of damage of MAJOR fuel restriction or vacuum situation in a fuel system), you would have noticed on your gauge or truck performance. This is why i dont agree with the diagnosis of your pump if you had proper fuel pressure to your pump at all times.

Sunir

Dan I have a quick question which ties into this discussion...I have a FASS 150/95 - 1008 system I got from Rip and I use an ISSPRO mechanical fuel pressure gauge with isolator (the kit from Diesel Manor)...I am seeing 13 to 13.5 psi at idle and down to 11.5 to 12 at WOT ...is this what I should be getting??... I've heard folks on the forum talking about higher numbers than me under both idle and WOT by around 3+ psi in each condition?? Please let me know...I used a stabilizer from Diesle Manor for the FP gauge and don't have a bouncing needle and I have the line coming directly off my standard factory VP44...

Diesel-Dan

You are dead nuts on where you should be. Dont listen to other with pressure...as they dont tell you if they have an HPFP (which are set up to 18ish PSI) or a 95 Series (which are about 1-2 PSI lower than the 150 series). For a 95 GPH 150 series kit....13.5 is perfect...and the pressure drop is perfect.

I will tell you this though....if you get any pressure drops in the future....ALWAYS check that isolator first......i got more gray hair from them!

dodgediesel

Dan, I've had 100% luck with the FASS until just recently. I kept popping fuses so they changed the motor out. All was well until just recently. If you heard the noise this pump makes now vs. when I replaced the motor, you would probably question it. I'll try to run the clear hose to see, maybe it's since it has gotten cold up here? When my Quad Race Box gets here, I'll hook up the fuel pressure sending unit and compare the pressures.

Sunir

thanks for the input Dan I appreciate it. Do you think I am ok in where I am or should I have gone with a setup (like a 150 GPH pump setup) which would give me a higher FP at idle and at WOT? I know the VP is a sensitive topic and I want to make sure I don't hurt it; what is the ideal PSI for the VP...I've heard too high = cavitation = bad and too low (like under 8 psi) and starvation = again bad! I want to know where do I fall in the range with what is perfect. I've been told that my FASS kit (the 150/95-1008) is good for upto 500hp...I don't plan on making any more than say between 300 - 400 at most...but what if I wnated to upgrade to a 150gph pump...would that be easy and inexpensive...sometimes I think I should have gone with the 150 setup from the start...but Rip said this one was all I'd need...even though you said my FP is good for the kit I have, I still wonder if it wouldn't help to have it more around the 15-17 psi range, if that would be better for the VP44??...please advise...