TBI wont build pressure.

Dboy

Dboy

Member
The other day my Scout acted like it ran out of gas and died on the side of the hyway, having just replaced my fuel cell I figured that I might have a cloged filter or that my fuel pump wasnt working, but both appear to be fine.

When I turn the key the relay kicks on and my fuel pump primes, but only builds pressure every once in a while. When it does I can fire it up and it runs for a few seconds untill the pressure slowlly goes down to zero.

Is it my pressure regulator?

Thanks.
 
When it loses pressure try to pinch the return line and see if the pressure spikes back up.
If it does then it's the regulator.
If it is difficult to build pressure then it's the probably the pump or something in the feed side.
 
bill usn-1 said:
when it loses pressure try to pinch the return line and see if the pressure spikes back up.
If it does then it's the regulator.
If it is difficult to build pressure then it's the probably the pump or something in the feed side.
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Thats good idea about pinching the return, but I figured it out. Somehow the system got a bubble or vabor locked. I unhooked the feed line from the cell and ran the pump, then hooked it back up and its running perfect.

Ready for wheeling on Saturday:cornut:
 
Well if you figured it out then what was the cause and what did you fix to keep it from happening again?

Are you sure you aren't creating a vacuum by not having a vented cap on your cell?
 
bill usn-1 said:
well if you figured it out then what was the cause and what did you fix to keep it from happening again?

Are you sure you aren't creating a vacuum by not having a vented cap on your cell?
Click to expand...

I have a vent from t in my return line that should keep everything breathing right.

It was either vapor lock or I finally blew whatever was causing the blockage through.
 
Mine would do stupid stuff like this in the beginning -- I decided it was the fuel pickup getting sucked to the side of the fuel cell. I cut about 10 inches off the pickup line and angle cut the end and it worked fine.

Is your pump still below the tank?
 
chris pucci said:
mine would do stupid stuff like this in the beginning -- I decided it was the fuel pickup getting sucked to the side of the fuel cell. I cut about 10 inches off the pickup line and angle cut the end and it worked fine.

Is your pump still below the tank?
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I didnt even think of that, thats probably what happened!!

Now with the taller cell my pumps probably about level with the top of the tank, should it be above or below? Never had a problem with it being above with my other cell.
 
dboy said:
I didnt even think of that, thats probably what happened!!

Now with the taller cell my pumps probably about level with the top of the tank, should it be above or below? Never had a problem with it being above with my other cell.
Click to expand...

Ideally you'd want it below the the bottom of the tank.

What pump are you running? Some prime great - some don't self prime very well at all.

Binderbound's pump wouldn't prime by itself at all - no matter what level the fuel was at - so when he would suck air for any reason - the truck would die and we'd have to pressurize the tank to make it work again.
 
chris pucci said:
ideally you'd want it below the the bottom of the tank.

What pump are you running? Some prime great - some don't self prime very well at all.

Binderbound's pump wouldn't prime by itself at all - no matter what level the fuel was at - so when he would suck air for any reason - the truck would die and we'd have to pressurize the tank to make it work again.
Click to expand...

Running the Ford inline pump.
 
Like chris said with the pump mounted near the bottom of the tank level it should work. I running the same Ford pump. Mine is on the frame rail as shown in bills write ups which puts in near the bottom of the tank. I run a stock cap from the auto parts store and notice that when I fill it up a lot of pressure escapes from the tank.
 
The hp pumps are for pushing. That's why Ford has a low pressure pump in the tank. I run a low pressure pump at/below my tank and it feeds the hp pump, I have never had a problem:icon_wink:
 
Daniel -
do you have an aldl scanner setup?

If not I have one you could borrow. I would say almost 99% certain that it won't show anything but you never know...
 
chris pucci said:
daniel -
do you have an aldl scanner setup?

If not I have one you could borrow. I would say almost 99% certain that it won't show anything but you never know...
Click to expand...

I have the cable but have changed laptops since I first got it and I cant find the disk that came with it, and it dosnt seem to want to read without it.
 
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