New FASS system- No pressure ??
 

I spent the day Thursday meticulously installing a new fass system on my truck. I did the pump only and used a different filter bracket than the fass. I used all Parker store push lock fittings, copper line for the pressure gauge. I installed everything hit the key, it primed right up and held a solid 45psi. I went to work yesterday (my job requires me to drive this truck all day long) and when a got out of the grocery store last night I hit the key, got my pressure, then it just started dropping like it had no fuel. I could hear the pump running, but no pressure. I check under the truck and no leaks. I finally got it to run, but still no pressure. Took it to my friends house and we double checked EVERYTHING.

We pulled the line from the suction tube and stuck it in a can of fuel- nothing.
Blew air back into tank through the suction line, it was not blocked
Checked the return line spring in pump, looked new

Here's the kicker- we installed another new pump and same results :dang:

I finally got pressure by blowing air into the tank, it picked up prime and off it went. I'm going to drive around today and see what happens, also I'm going to switch back to my other pump.

What gives?? For the life of me I can't figure out what would cause this. I do have a full tank of fuel and this pump worked all day long. After my install I had appx 7 gallons of fuel in the tank, and now its full. Return line is clear.
:humm:
Open to any and all suggestions. Thanks guys!

Is the suction line you are using rated for suction. If not, it could be collapsing on itself while the pump is running, even if you don't see it. Just a thought.

Its the line that came with the fass system, I would assume so.

u got trash in the tank sounds like

Glad to see you made it here Paul......I am wondering if you had air in the filters. When I change my filters I have to leave the fuel filter cracked open and turn on the pump until fuel come out of the filter and then tighten it back up and she's good to go. Another thing is if the tank is low that stupid and you stop short that fuel runs away from that damn draw straw and you'll lose pressure. It will come back up but the draw straws SUCK. I want to put a Hellman Sump in my tank to fix it.

I vote air in the filters, Crack them open and It'll prime back. The new high flow modules will work for all these trucks, but you'll have to run the return line to a draw straw in the module instead of in the filler hose!

Will that stop the problem of the draw straw sucking air at a 1/4 tank and under?

Sure will!

I assume that is the new Draw Straw I correct? DO you have them in stock? I am sick of that pressure drop around a 1/4 tank that I get with the FASS suction tube. PM me a price if you would. Sorry for jacking your post Paul....:moon:

I'll PM ya a price when I get to the shop. I'm at a buddies house right now.

Great. I appreciate it. I can't do anything until Monday any.

Thats ok Phil, I'm jacking your turbo :tu:

Nahh man it's all yours as long as I get to go for a ride after it gets installed. Plus if I install this new module this will fix your 1/4 tank issues as well....so i can be the tester.

Lucas could you post the correct park number for the guys that are sick of the 1/4 tank issues? thx.

Ok...
I didn't see anyone ask,so I will....

Did you use the FASS drawstraw and mount it in the tank where they showed you?

What about the length of the drawstraw,did you possibly cut it a tad long thus it sucks closed by pulling the tank bottom up and blocking it?.

If you cut the drawstraw too short it will do exactly like you describe also.

Hammer- They say 2 quarters stacked, I gave it a little extra room, that seemed too close to me, I always refuel at 1/4 tank anyhow.

You guys are saying crack the filters, My filters are after the pump on the pressure side. I'll still try it. I drove around yesterday with no problems, I hope this doesn't turn into one of those things...

If you went more than the 2 quarters they wanted then you may suck air a tad sooner than those who did the quarter trick.I did the quarter deal when we installed mine a few years ago and when the tone goes off for low fuel you better be finding a station soon or your walking.Also of note,if your on a level road with minimal turns then you might go a tad longer once the tone goes off in the dash but let the tank slosh some and your walking as it will suck the filters dry quickly.......Andy

I have noticed something as well.....since our tanks are poly....I did the two quarter trick on my straw. Now like most the tank was empty and on the garage floor. I noticed the gap grows when the tank is full and hung back on the frame as the bottom defects a little.....now whe full it isn't a problem but how much does the tank deform at say a 1/4 tank? I'll wait to get a PM about this new module and maybe give it a try...since it uses the factory module as the pick-up point it should work as I never had this problem when using it but the lines were all corroded at the top and leaking so I opted for the draw straw.

Update-
3/4 tank fuel, flat road, I lost pressure twice in 8 mile stretch. I pulled over and cracked filters loose, the pressure is back. It got me thinking that I have my filters plumbed wrong. I've got fuel coming into the water sep. through the larger center hole and out the smaller holes around the edge, the into my filter through the smaller outer holes then out the center to the Injector pump. I'm going to go switch my line going in to the water sep.

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I switched the lines, here is a few pictures of the install.
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Ok...
First lets start with an easy question....

What model FASS is that you are using?.

You need to figure out what is the feed line to those filter heads and which is out line to the motor.by the look of it your plumbing into the top of your water separator and out the side and then you go in the side and out the top of the filter head.To me from the water sep you need to go to the top of the of the filter head and out the side to the motor.

It all looks to me like you would have been better off buying the complete FASS w/filters and be done with it.The lift pump you have does nothing for air/fuel separation and I am willing to bet with the price of the filters,filter heads and brackets you could have purchased a 150/180-1010@45psi which is what is supposed to be for the 12v trucks.

I am in firm belief that any electrical pump with less than 180gph will not sufficently feed a tuned 12v enough fuel to make efficent power.I am certain that if you would call Lowfly(Jim),the warranty man at FASS,he would also tell you the same thing as this was a recent discussion I had with him when my pump failed recently...............Andy

I was sold the 150/90-1010 and I have not had one bit of issues....but it wouldn't suprise me to be underated coming from the crook that sold it to me. He's been known to take advantage of people to make a buck. Regardless that is a different discussion. I think he had the filter head laying around and wanted to use it and save some money vs the unit with filters.....

HAmmer- That is not the pump I ordered in the truck its one my buddy had, at any rate the one I have is the replacement for that model, its 200 gph and adjustable up to 90 psi, I have it set at 45. We just swapped pumps to see if the pump was the problem, I'm going to install it later this week. Its plumbed correctly in the pic, as you described, the ports on the side feed the center of the filter, and the ones on the top run the outer holes on the filter.I had the to sides run together to start with then out the top to the engine. I only have a little over 40 bucks in my filter setup with bracket and filters so I saved money over the fass system. I just wanted easier filter access. I just took an hour drive over smooth straight roads and bumpy windy back roads, and all worked good, Tomorrow will be the test, I need the truck all day for work.
Think having that filter backwards could have caused the problem I'm having??

:jump: And here it is! Anyone who runs amsoil diesel concentrate will recognize this little round cardboard as the piece that seals the cap in the bottle. Its just big enough to block the draw straw, light enough to float around, and conveniently enough it stayed at the bottom of the tank. Found this and also cut a notch up about 3/8 inch up the pick up to prevent anything from ever getting sucked up to it again.
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good to see ya goe er fixed..........you need to be more careful dude! hope this doesnt happen to yer oil :ouch:

glad it wasnt foil , Red Man Snuff? Must be regional for you

Glad you found your issue.

I'd be wary of cutting that notch you made though.

With it being 3/8" higher up the draw straw means once the fuel level drops to that notch you will loose the suction and loose prime.It just lowered your usable fuel amount in the tank by 3/8" as once the level hits that notch your done.

I do run alot of fuel through this truck, I was definitely an accident on dropping it in, Don't worry Whit, I'll keep the oil clean :rocking:
Hammer, the way the fuel sloshes around in that tank, and as many hills are around here, that 3/8 isn't even going to be noticeable, Like I said earlier I always refuel at 1/4 tank because that's when my gauge quits working.

Glad to see you found it Paul....that is crazy. I would have never though of something like that.