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Discussion Starter · #1 · (Edited)
I know I've posted this here before, and I hate asking the same question over, but this post is a little more extensive and I'm definitely getting a constant induction of air into the low pressure side of my fuel system... and it's bugging the hell out of me because it wasn't like this before.

If anyone has any ideas I'd really appreciate it.

Ok, when I first got my truck I put a BD warning light kit on it. Whenever I would turn the key on and wait for the "wait to start" light to go off the intank lift pump would build up enough pressure to turn off the warning light and that pressure would hold for a good 20 seconds before it leaked down enough to make the light come on again.

So I decided to put a holly on the frame and did away with the quick connect on the tank outlet and ran 3/8 line all the way from the tank, to the holley and up to the fuel filter inlet. Tha't when I started having the problem of pressure quickly bleeding out of the fuel system. I'd turn the key and pressure would build and within 3 seconds be back to zero. So I'd crack the inlet to the VP44 and bump the starter. You could hear air escaping and I'd tighten it when all the air was out. Now the system would hold pressure again. But as soon as I drove it around for even a half hour the pressure would drop quick again, and there was more air in the lines.

So I took the holley off and went back to the stock steel lines. Except now I have 3/8 inch line from the outlet at the fuel tank to the beginning of the metal line inside the frame, and from the end of the metal line to the inlet of the fuel filter. Every hose clamp is tight. I even disconnected the fuel line at the fuel filter inlet and pumped 5 psi of air pressure both going to the tank and going into the fuel filter to the VP. I had a gauge right on the air hose and both directions had absolutely no leakdown. Put it all back together and blead it out real good at the VP. And it's back to the same thing.

Does anyone have any idea what's going on? It didn't act this way when it was stock, and it's just about back to stock now aside from the two pieces of 3/8 replacing the quick connects. But they're TIGHT. It's got to be something when the intank pump is running, maybe it's sucking up air somehow.

The truck runs fine but I know there's more air in the fuel than normal. That can't be good.
 

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maybe the pickup tube inside the tank has a crack in it above the fuel level
 

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Discussion Starter · #3 ·
maybe the pickup tube inside the tank has a crack in it above the fuel level
Yeah, one guy on another board said his pickup tube was rubbing against a bolt and developed a hole. When he had a full tank there was no problem, when it went below the hole in the pickup tube then he had problems.

That's one thing I'm going to check by filling the tank completely and see if anything changes.
 
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