Diesel_Dan: FASS passed the 5 gal bucket test, what's next

[JCleary]

Diesel_Dan: FASS passed the 5 gal bucket test, what's next?

I PM'd you and you responded to me on one of the other sites (recommending the bucket test), but basically my problem is this:



I bought a FASS 150 in January. I was impressed at how quiet it was since everyone claimed how loud they were. All was good until last month when the pump started cavitating. First a little at a time, now it's pretty much constant. Pressure fluctuates about 2-3 psi up and down (20-23) and the volume of the squealing changes.



I took my truck to a local diesel shop, paid them 3 hours to diagnose the problem at $70/hr.



They put a clear line on the discharge hose and pumped the fuel into another tank. No bubbles, and the pump would run quietly until a kink was intentionally placed in the hose to give a little resistance. As soon as pressure built up, the pump started squealing. Still no air bubbles.



They then dropped the tank, checked the connections and fittings, lowered the pickup tube. No leaks according to them, so they buttoned it up and it's back on the road. It still squeals, and the pressure fluctuates.



What can I do to fix this issue? I find it annoying and I will fix the problem. I would rather keep the FASS than replace it with a competitive product.



The FASS I have has a later production date, but it is not so new as to have the new motor and relay.



Thanks.

 

[BlakeDavis]

I have noticed the same thing with my 95 but didnt think much of it. The pump is louder at some times that others and fuel pressure fluctuates a few lbs. I will keep an eye on this thread to see what develops. I'll also be more than happy to answer any questions if i need to also.

 

[steved]

Mine cavitates from time to time... I thought that was normal without installing a larger pickup in the tank? Mine ususally does it at and below 1/4 tank...



steved

 

[JCleary]

Mine cavitates from time to time... I thought that was normal without installing a larger pickup in the tank? Mine ususally does it at and below 1/4 tank...



steved

I do have the larger pickup. One of the drawbacks of the new pickup is that I can only go to 1/4 tank before my fuel pressure will drop to 5psi, then swing back up to 20. Bottom line is that 1/4 = Empty. I have a 25 gallon tank now. It doesn't make much noise when it does this. The squealing cavitation is pretty much constant now, regardless of fuel level (over 1/4).



The pump was nearly silent in the beginning, just a little whir you could hear when the motor was off.

 

[steved]

I do have the larger pickup. One of the drawbacks of the new pickup is that I can only go to 1/4 tank before my fuel pressure will drop to 5psi, then swing back up to 20. Bottom line is that 1/4 = Empty. I have a 25 gallon tank now. It doesn't make much noise when it does this. The squealing cavitation is pretty much constant now, regardless of fuel level (over 1/4).



The pump was nearly silent in the beginning, just a little whir you could hear when the motor was off.

With the larger pickup, it shouldn't do it at all... from what I have read, that was the supposed cure for the cavitating FASS??



Are you sure it's cavitating? I almost wonder about bad bearings and while it might pump fine under a "no load" condition, as soon as it has a load applied, things get out of wack??? Maybe?



steved

 

[JCleary]

When I think about it, you may be correct. It kind of sounds like a computer fan when it's worn out, but super loud.



I wonder if that's a warranty thing? I'd hate to pay more money to have the thing swapped out and find out that's not the problem...

 

[steved]

I'm hoping D_D chimes in here sooner than later...



He's the man with the answers.



steved

 

[BPonci]

Sooner than you think!

 

[LowFly]

HUH... . The only way i found this thread was Brad from Ponci's called me and told me about it... . i have searched for "FASS" about 4 times between yesterday and today and this thread has never popped up..... what’s up with that? Moot point..... im here.....



If the pump is squealing... . could be a spun bearing. I have a hand full do this. Is this a FASS we are talking about right? Not a HPFP? People get those 2 mixed up all the time.



The HPFP i can see squealing if the spring and check ball resonate. A simple spring and ball change can stop this. BUT i have only seen this on the HPFP, not the FASS.



What you can try to do is block off the return and pressure lines at the same time. Dead head the pump. If the spring is resonating, the pitch should change somewhat. If it doesn’t... and stays consistent, we may have a bearing issue here. Your pump, if bought in Jan, should still be under wnty. Get with Brad at Ponci's and give him your serial number.



Brad, once you get this info, call me..... thanks!



ALSO... note for the suction tube kit... a good rule of thumb for install depth is, stack 2 quarters. They should just fit between the tank and the tube. Could suck air if higher. BUT just get fuel when your light comes on. Good rule of thumb.



The pump will make noise from time to time when air is being fed back to the tank... ... it will gurgle a bit and clear up... . depends on how much driving has been done. Pressure can drop just a touch when this happens... . depending on how sensitive your gauge is... . i have a cranked down needle valve on mine... and gauge operation is slow... . so i don’t see this.

 

[tazzen]

Dan,



My fass pump has gotton really loud also , sounds like a really bad vibration and does it all the time. Even if the tank is full or half empty. Now my fuel pressure stays around 16 psi. @ idle and cruising. WOT drops to 14 psi. I had the fass with filters that made some noise but not like this one. So do i have a problem? I was about to call my installer when i seen this thread.



Thanks,

Ed

 

[LowFly]

Dan,



My fass pump has gotton really loud also , sounds like a really bad vibration and does it all the time. Even if the tank is full or half empty. Now my fuel pressure stays around 16 psi. @ idle and cruising. WOT drops to 14 psi. I had the fass with filters that made some noise but not like this one. So do i have a problem? I was about to call my installer when i seen this thread.



Thanks,

Ed

OK..... Cavitation will cause noise. You can test for this. You can slowly pinch off the suction line of the pump and get an idea for what you are listening for. Open the drain on the Water Sep with the pump running (This will allow air to brake prime on the motor). If the pump gets real quiet. Your bearings are ok. Close drain before you shut the pump off or you will have a mess.



Pull your suction line off the tank and return line off the return manifold and place in a bucket of fuel. Run the pump. Is it quieter? If it is, you may need to address some in tank issues. OR check suction line to make sure no air is being sucked in.



A bad bearing in the motor is VERY noticeable. There will be no doubt in your mind. Like i said before... open the water sep drain when the pump is running. If it still sounds like its grinding gravel... ... . call your dealer with your serial number.



ALSO we talked to our motor guys this week. The motor on the FASS/HPFP needs about 40 Hrs of run time for the brushes to completely seat. Until this happens, the motor may sound loud.

 

[zstroken]

Dan, I called you earlier in the week on the high pressure 12V 45PSI unit, it looks like I have an intake issue, my clear line that used to be clear is discolored, so I thought it had fuel in it. I am pulling the bed off this weekend to examine the intank issue. Did you get the serial numbers for the other Fass units yet? I want to make sure the warranty gets squared away on those. Thanks for the quick response.

Dan

 

[LowFly]

Dan, I called you earlier in the week on the high pressure 12V 45PSI unit, it looks like I have an intake issue, my clear line that used to be clear is discolored, so I thought it had fuel in it. I am pulling the bed off this weekend to examine the intank issue. Did you get the serial numbers for the other Fass units yet? I want to make sure the warranty gets squared away on those. Thanks for the quick response.

Dan

Keep me posted on what you find. I got the SN numbers..... i will take care of it... ...



As for the fuel line... ... our display units we use for shows..... we have to change the line on them constantly... dont take long for the line to "yellow"



This thead is STILL not showing on a search for FASS... ... what gives????