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Help! LML FASS lift pump high psi!!!

8K views 17 replies 5 participants last post by  DRAElectrician 
#1 ·
So I started smelling diesel fuel on my way home tonight. Popped the hood when I got home with the truck still running, and all I saw was fuel squirting up like a water fountain. Fuel was everywhere. I didn't get a good look to see where it was coming from because I ran back in the cab to shut it off....but before I shut it off I could hear my Fass 150 screaming higher than ever...I checked the gauge really quick and it was pegged...the highest the gauge will read is 15psi, so who knows what it was really at.

So my questions are...

Has anyone ever heard of this or have any advice?

Where would the fuel be squirting from? I'm scared to start it back up. I unplugged my fass fuse and planned on just seeing what it was going to do in the morning

:(:mad:
 
#2 ·
I had to replace the low side fuel pressure/vacuum sensor it was leaking fuel all over my oilpan/downpipe area awhile back. the sensor was like 44 bucks. Since the fass supplys the fuel it will cause a leak in the sensor after awhile, doesn't always happen but it did on my truck.
 
#4 ·
I really wish I would've looked to see where the fuel was coming from. I haven't started it yet this morning. Hopefully it's an easy fix. I didn't think the 9th injector could leak since it's cut off with tuning? Would the leak cause my fass pump to be running that high of a psi? Or do you think something is wrong with my fass pump as well
 
#5 ·
Fuel still comes to that line and is pressurized, then sent back through I assume. I was removing the Def fill tube and snagged the injector line that on the passenger side, behind the fuel filter. The hard line that the bung is connected to was zip tied out of the way but I must have caught it somehow cause the line popped out of the little clips it's in and was spraying fuel like a super soaker everywhere. I'll see if I can find an expanded view of what I'm talking about.
 
#7 ·


Between numbers 2 and 3 is where I was leaking. It's like a little bracket that holds it in place, my Def fill tube had got stuck on it and ripped the line out of the bracket. My phuck up was caused by me, but my buddies did the same thing when we were mudding.
 
#11 ·
Okay so I don't think my fass pump was the issue. I don't think it was running at 15 psi or higher. I checked my gauge yesterday while the truck was off and the needle was stuck at 7psi...so my gauge is definitely broken and is causing it to look like it's running higher than normal. I'll be getting a new gauge this weekend. No more leaks as far as I can tell though. Truck drives fine and holds pressure. Rail pressure still hits 29kpsi. I do see some fuel sitting down at the bottom of the motor though. Just like a puddle that's slowly burning off. But I haven't seen any drips on the ground since that night. It's the strangest thing....
 
#13 ·
Is your gauge under the hood, that's where I had mine and it actually leaked out the face of the gauge and I had to replace it. It was a cheap gauge I have since replace it with an auto meter gauge we'll see how it holds up, lots of vibration and heat under the hood.
 
#17 ·
My pump done the same thing. It came from sensor beside snubbed box. Mine done it today I had same gauge and all. The ball was stuck in spring. I hope my fuel system isn't fried.
 
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