well about 4-6 months ago i installed a fass 150 gph lift pump . now about a month ago i have a real hard time getting it started it was just like one day it decided to take like a minute for it to finally kick over and fire up.its been the same ever since. sometimes my low pressure light will come on only when it first starts it will flicker for a a little while like mabe 30-45 sec. it never did this before.but here comes the kicker. sometimes when i pop the gas cap to fill up it will literally shoot off.sometimes i even get fuel leaking out of the filler neck and also sometimes pouring out of the top of the vent hose on top of the tank itself .also if i park on an incline with the nose of the truck downhill it will start fine. what gives? any ideas and insight would be greatly appreciated.there are no leaks elsewhere as far as fuel( just my oil pan and water pump gasket need a fix'in). would it be a bad lift pump already? i replaced the fuel filter going into the fass and the stock fuel filtr like 2-3 months ago.i am out of ideas and have gone over the install looking for something and keep coming up empty handed!!! please help!!anyone else have this problem?

 

It sounds like you have a venting problem with your tank. im not sure if the fuel cap is vented or if the tank has its own vent but the tank has to be able to breathe somehow.

 

that model still has brushes in it we just replaced them in a customer fass system you might wanna check that and see if they are bad the new ones dont have them they got smarter

 

When I first installed my 95gph HPFP (FASSII) the truck was doing similar things. Parked downhill, no problem starting. Parked flat or uphill, or shut-off for longer than four to six hours, I'd have to bump the starter a couple times. Kind of like losing prime, or when you change the fuel filter.
The solution......a second hose clamp where the pump to tank hose connects to the tank fitting. I never used the quick connect that came with the pump because it just didn't feel like an airtight seal....it was kinda loose
It's been over 20k miles now and all kinds of weather, no problems.

 

jeep: i got a new gas gas cap even though the old one seemed fine and both are vented!! still got the problem but thanks for the heads up . It seems like when i get on it hard like WOT the diesel pours out the filler neck and out the fuel door it looks like a shower head coming out of there!!

white truck : i will look into that tonight!! let ya know

moose: i am gonna do that tonight too!! thanks alot for the info. i did use a clamp on the delivery hose also since i thought the same thing. i am gonna put on another one.

thanks all!! heres too yall!!

 

I'm guessing that you cut your stock filler hose to close to the filler cap and since you have the 150gph pump you have way to much pressure on your return line causing it to come out of the cap or you have the metal piece in the filler neck pointing the wrong direction. If I fill up my truck with my engine running I can hear a lot of fuel flowing through the return but mine is down close to the tank so it doesn't splash out and it is the 95gph pump. As far as the pump not starting that is probably an issue with your brushes. They will send you a new set but a quick fix is to take them out and turn them around.

 

well heres the scoop:

no luck with the 2 nd clamp on the supply line on the tank
still takes for ever to start if not on a decline.

ellerman: during the install i didnt cut the filler neck at all or the vent tube that goes to the filler neck on the tank. i am a bit confused as too why it would get cut at all. i am useing the stock return line from the injection pump. should i upgrade?

new problem brewing now: I am getting a flutter constant drop in rpm's at idle like a consistant tapping on the throttle but just the opposite.

i think i am going to have to take it to the diesel shop real soon. this fueling issue is driving me crazy!!!

any more help would be appreciated!!!!!!!!!!!!!!!!

 

Tug
That return from the pump has to be in the system. That particular component is NOT an option. I get the impression you that your mods use alot of fuel, but that pump system has to be able to recirculate a certain percentage of the fuel. If not, it will create a mass of air in the system for you, hence the hard starts. When you park the truck on the down grade, it allows the built up air to rise to top so to speak like CO2 from your favorite Barley pop. Your flutter, RPM drop and starting issue is from the fact the pump is churning the fuel in to a air infused mess and your rig can't completely or efficiently burn all of the fuel you are delivering. You are forcefeeding the fuel to the pump, and the return pressure you create by not allowing the FASS pump to recirc some of the fuel is enough to cause the burping from the tank,irregardless of how much or how little fuel you have in the tank! My advice to you is to get that recirc connection into place in your tank filler tube, ensure all connections are secure and I believe your "Fuel issue" will be fine.
R/
Eric

 

You may have the Older motor. Brush fix: Pull the brushes out and sand them lightly with some emery cloth. Reinstall and put a dab of RTV around the edge of the Brush Cap to seal better. MAKE SURE you have good ground/Pos (OR updated harness with the relay) connection at the BATT.

The grounding brush (The one on the outside of the FASS closest to the sheet metal of the truck) is usually the problem child. Make sure you have the updated caps (They have a brim of sorts that cover the brush recess on the motor.). Any FASS dealer can get new brushes and Updated caps. Seal them with RTV and i bet your issues will go away. The new motors are not brushless. They are just a sealed better to keep electrolysis from being an issue.

BUT i dont see this being your issue here.......

Check your Return line hook up for the FASS. Like ellerman said, you might have it turned upstream. The only way to get the adapter into the filler neck line is to cut it...so i dont understand how you got it to work otherwise. Look back on the install instructions at www.Dieselpp.com to see if you have it in the right way.

YOU HAVE TO HAVE A RETURN LINE TAPPED INTO THE FILLER NECK FOR THE FASS. OR IT WONT WORK CORRECTLY!!! Air will just build up in the fuel filter until it just pushes the fuel out....then you will loose prime, hard starts, and surging can occur. Parking on an decline allows fuel from the water separator to siphon in to the fuel filter....allowing the truck to start. I would highly recommend checking that return line!!!!!! This is how the aerated fuel is reticulated back into the tank.

Building pressure is a venting issue. If your tank could vent, no pressure would be present.

Another thing that might cause a hard start is a check ball in the base plate that might be sticking. Its not likely on yours though. We stared using a 5/8" ball instead of a 3/4" ball to stop this issue. BUT its worth checking. You will have to separate the T-Block, Motor Support, and Motor from the base plate to check it. Should be 2 o-rings and a ball. The ball should be sitting in the base plate over the suction side orifice. It should be free...not stuck in anything.

We have never had any issues with the snap on fitting at the tank. Check the pipe thread fittings going into the FASS and going to the Injection pump. Make sure you use some thread sealant on thoes fittings. They will leak/suck air if you dont.

You need to check to see what fuel pressure is. Its really hard to tell whats going on with out that reading. We dont know if its cavitating, fuel restriction or what.

SO, is the FASS Motor running normally? No loud noises? Runs for a sec when you turn on the key, runs for 20 sec when you bump the engine?

Your fuel tank having pressure is not normal...and might be some of the issue.

Get us some more information and I/we would love to help you more!

EDIT: SN Upgrade BRAKES----

2546 and up started using the 5/8" ball instead of the 3/4" like stated above

2770 and up have the harrness with the relay

3862 and up have the high pressure releif in the T-block

4931 and up have the new Non-servicable motors (These are the most updated kits to date)

 

Another Question: Do you have the FASS or the HPFP (High Pressure Fuel Pump)?