EFI Low Fuel Pressure

[BroncoinAlaska]

Specs:
BC Bronco EFI Fuel Tank w/AN Fittings
Walbro 255 LPH submersible pump
BC Bronco Deluxe fuel line with fuel gauge
24lb Ford Racing Injectors
Stock Mustang Fuel Rail
Aeromotive Fuel Pressure Regulator

Got 50 miles away from home stopped for lunch. Bronco ran great. Jumped back in fired right up, got a call on my phone shut the Bronco off. Tried to start it back up NOTHING. Fuel pressure was reading 10psi. Pulled the line off before the filter and had fuel come out when I turned the key to the on position. Moneyed with it till I had to get a tow.
Figured maybe bad gas swapped out the filter and the pressure jumped up to 18psi. Thought the strainer might be clogged. Dropped the tank installed new strainer. Same 18psi.
Clamps for the submersible fuel line are the full O not the worm style. But the two clamps are different sizes. One is 13-15mm and the other is 14-16mm. Are these the right sizes? Where can I replace the S shaped submersible fuel line? I am pretty sure it came with the Walbro pump.

Any thing else that I missed wile I have the tank on the ground?

 

[Viperwolf1]

http://www.oreillyauto.com/site/c/search.oap?keyword=submersible+fuel+line

 

[sp71eb]

Might be a bad pump. I'm sure it is new but one thing that I found with my build is that if you put a bunch of new parts on a truck you are going to have some bad new parts. Also do you have the tank grounded or just getting ground through the frame? Also are your lines holding pressure when the key is turned off?

 

[Broncobowsher]

Pinch the return line and check the pressure before you go too far into the pump change.
If the regulator is blown open you won't get much pressure. But pinching the return will spike the pressure above normal.

 

[Ourobos]

If the regulator is bad you will be free flowing fuel right back to the pump as Broncobowsher mentioned, sounds like the problem to me.

 

[BroncoinAlaska]

http://www.oreillyauto.com/site/c/search.oap?keyword=submersible+fuel+line

The submersible line is molded into an S shape. Wouldn't using strait replacement line cause a kink and restrict the flow?

 

[BroncoinAlaska]

Also do you have the tank grounded or just getting ground through the frame? Also are your lines holding pressure when the key is turned off?

Tank is grounded at the frame with a large ground strap. Frame is clean and well grounded.

How long do the lines have to hold pressure? And is any bleed off ok? I will check when I get the tank back in tomorrow.

 

[Rox Crusher]

my aeromotive pump came with a piece of straight EFI submersable hose

I too would suspect the regulator

 

[BroncoinAlaska]

my aeromotive pump came with a piece of straight EFI submersable hose

I too would suspect the regulator

So clamping off the return line would simulate the regulator closing and not bleeding off the pressure?

Would the regulator be bad or out of adjustment?

 

[BroncoinAlaska]

What about the different sized O rings on the submersible line? Are they the right size?

 

[Rox Crusher]

So clamping off the return line would simulate the regulator closing and not bleeding off the pressure?

Would the regulator be bad or out of adjustment?

If you can pinch the return line with something like pliers or channel lock it would simulate a properly functioning regulator.

Most people have a standard regulator which isn't adjustable, it is either good or bad.

Maybe you have an adjustable regulator though ?

 

[Viperwolf1]

The submersible line is molded into an S shape. Wouldn't using strait replacement line cause a kink and restrict the flow?

You're going to have a hell of a time trying to find a S shaped submersible hose. I'd find a way to make the straight piece work.

 

[DirtDonk]

Not sure if it comes with the pumps or not. You could call BC to see if they've got any laying around I would think.
Even if it comes with the pumps, there's gotta' be someone around that has them individually. Well, I would hope anyway. More likely it's like Viper said with a "hell of a time" but hey, it's still worth a call or two before going to plan-b I would think.

I didn't see where you said, but why do you think you need to replace it anyway?
And if you determine it's the pump, won't a new one come with it?

Do you have the tank out yet? Were you able to verify that none of the connections were simply loose or broken?
Be interested to hear what your results are when you pinch the line and test the pressure again.

Good luck.

Paul

 

[ENDLIFE]

I made the Walbro 255lph mistake as well. I cleaned the hell out of my tank so I thought, but when I fired up my fuel pump for the first time it was LOUD. It would run like a hot rod for a while, but then it would start to surge and run horribly from a stop light. I'm also running a AEM FPR, it doesn't hold residual pressure, but my rig starts right away.I went with a Denso fuel pump, it's quiet, and I waiting for the problem to come back but it hasn't. Also the hose I used made installation a breeze at a fraction of a cost for submersible fuel line.

 

[welndmn]

I'll echo everyone else, pinch your return line off.
If the pressure goes up, you have a leaky regulator or leaking injector.

 

[dclack]

Not sure if you can find it separate or not, but Foxbody Mustang pumps come with a 'S' shaped submersible hose... http://www.oreillyauto.com/site/c/d...=Search_C0401_1133952_3707&pt=C0401&ppt=C0025

 

[KyleQ]

All those expensive parts and nothing but trouble... seeing a trend. Simple is where it is at - externally mounted pump on the frame rail with a simple fuel filter before it. Everything is accessible and replaceable on the shoulder of the road or in a parking lot.

Nothing wrong with the stock fuel rail and off the shelf regulator-

Good luck with your issue - I agree that if you block the return and the pressure increases its the regulator... If you had a leaky injector it would run like crap-