[OEM+]

Good day everyone.

I have a 2010 LMM (200K miles) with a (newer model) FASS 150. Recently I have been having no prime(no start) with the fuel level between 1/4 and 1/2 after the truck sits for about a hour. If I remove the fuse on the LP the truck runs as it should even past 1/4 tank (i have always had 1/4 tank issues as have many others), once it is manually primed again. It will also come to life with the LP plugged in but only after I manually prime it.

I do not see any fuel leaks from any of the hoses or the OEM filter head. The only variable is that the LP has CAT filters on it, and the fuel one is one of the tall boys. I do not currently have a filter to change it out but that is my next step to eliminate the variable. Any help is appreciated.

I guess I can add that I think my fuel froze in my filter when it was down to 1 degree (was driving then limp mode, change fuel filter light etc), i cannot remember this issue happening before that come to think of it, but i did change the OEM filter due to gelled fuel.

Also, theres a rust bubble on my CAT filter, never seen that before. No it does not leak, just throwing all the information I have to the wall.

 

[bellassaiw10]

Factory head probably needs rebuilt, or you need a sump or a draw start installed because its not pulling all the fuel

You say 1/4 tank issues, as in what exactly?

 

[mray]

Probably need a sump or new draw straw.

 

[OEM+]

Factory head probably needs rebuilt, or you need a sump or a draw start installed because its not pulling all the fuel

You say 1/4 tank issues, as in what exactly?

When the LP was first installed around 1/4 tank it would struggle to start, but it would. Now it’s not turning over with even more fuel in the tank. I’m leaning towards replacing the head but it’s confusing as to why it only happens when the LP is in play. Maybe the added pressure?

 

[OEM+]

Probably need a sump or new draw straw.

it’s odd to me that this is happening after having a LP for a few thousand miles though.

 

[mray]

If it was the filter head and the lift pump is working you would see it leaking, should be able to open the bleed screw and have fuel coming out with the key on. If no fuel there I would check the lift pump, something may have happen in the tank that is not visible. When you had it running did you check desired fuel pressure against actual fuel pressure, may also have a weak CP3 pump.

 

[OEM+]

If it was the filter head and the lift pump is working you would see it leaking, should be able to open the bleed screw and have fuel coming out with the key on. If no fuel there I would check the lift pump, something may have happen in the tank that is not visible. When you had it running did you check desired fuel pressure against actual fuel pressure, may also have a weak CP3 pump.

Desired vs requested is always spot on. With or without the LP in play. Without it, the truck runs perfectly fine everywhere between idle and WOT all the way up to 26k psi

 

[OEM+]

If it was the filter head and the lift pump is working you would see it leaking, should be able to open the bleed screw and have fuel coming out with the key on. If no fuel there I would check the lift pump, something may have happen in the tank that is not visible. When you had it running did you check desired fuel pressure against actual fuel pressure, may also have a weak CP3 pump.

Update to the update. I plugged the LP back up. Cracked the screw and fuel came quickly. Primer is hard. Truck started right up.
I’ll leave it for a hour or so and see if it leaks down again

 

[Ron Nielson]

Either your lift pump has too much pressure when starting, or your filter head has a problem. I'm leaning toward the latter.

 

[OEM+]

Either your lift pump has too much pressure when starting, or your filter head has a problem. I'm leaning toward the latter.

same here. Just getting consensus before I buy a new one cause for the life of me I can’t see a leak on the filter head. I have the gasket kit to rebuild it but I’ve heard mixed reviews.

 

[Ron Nielson]

It is very common to lean vacuum, but not leak to the outside. Some have had success with the rebuild kit, but many have done the rebuild, then bought a new one when the rebuild failed. The rebuild kit is cheap and if your truck starts reliably, you know where the problem is, and you can purchase a new one at your convenience knowing the problem has been solved and you won't be wasting your money.

 

[OEM+]

It is very common to lean vacuum, but not leak to the outside. Some have had success with the rebuild kit, but many have done the rebuild, then bought a new one when the rebuild failed. The rebuild kit is cheap and if your truck starts reliably, you know where the problem is, and you can purchase a new one at your convenience knowing the problem has been solved and you won't be wasting your money.

lucky for me I already bought the MA rebuilt kit. Just couldn’t get those damn hoses off so I put it on the shelf. Guess it’s on the board again.

 

[OEM+]

Just went out and the primer was soft, but the truck turned over.

 

[OEM+]

Update: didn’t touch primer truck is at 1/4 which is below where it was having hard starts. Turned the LP on and cracked open the bleeder screw on the last attempt. So I just started it as normal and it gave me the hesitation I’ve become used to and fired right up. Maybe I just had too much air in the system? Who knows. I’ll check it in the morning. Thanks to all so far!

 

[bellassaiw10]

If your primer is soft after an hr it is 100% your filter head. It won’t necessarily leak either, mine never leaked even with 10psi coming from the lift pump but if I let it sit for a few days it would lose prime.

I ended up ordering a whole new head as it started leaking again after rebuilding it.

The LP shouldnt make any difference with your starting problem, if anything it should get better with the LP on.

Are you sure your fuel lines are hooked up correctly from the LP to the truck? Only way I could see the issue getting worse with the LP in play.

 

[OEM+]

If your primer is soft after an hr it is 100% your filter head. It won’t necessarily leak either, mine never leaked even with 10psi coming from the lift pump but if I let it sit for a few days it would lose prime.

I ended up ordering a whole new head as it started leaking again after rebuilding it.

The LP shouldnt make any difference with your starting problem, if anything it should get better with the LP on.

Are you sure your fuel lines are hooked up correctly from the LP to the truck? Only way I could see the issue getting worse with the LP in play.

I’m gonna order a head just for peace of mind. Even though at this exact moment it seems fixed but who knows.

the only thing about my LP that I question is the filter placement as FASS shows two opposite filter installation directions in a few places. Right now I have the fuel filter on the side with the draw tube. With the LP on it sprays fuel out of the prime screw so I believe it’s all in working order.

I’m gonna let it sit overnight and mess with it tomorrow.

 

[lowe1971]

Bypass the filter head and see what it does.

 

[CrazyCowboy]

This is the best setup for replacing the filter head. There’s an option for the Aeroquip fuel lines.

DmaxStore Ultimate Fuel Filter Head Package (RACOR) | DMAX Store

dmaxstore.com

 

[OEM+]

Bypass the filter head and see what it does.

I saw a few homemade rigs I may try. Any suggestions?

 

[OEM+]

This is the best setup for replacing the filter head. There’s an option for the Aeroquip fuel lines.

DmaxStore Ultimate Fuel Filter Head Package (RACOR) | DMAX Store

dmaxstore.com

much appreciated!