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obs addiction
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1,054 Posts
Discussion Starter #1
I'm chasing a fuel issue on my brothers truck. 1996 f250 Auto truck has ts chip 6637 and 4in exhaust for mods

For some reason the truck is starving for fuel under light driving, barley pulls it self along at 60 mph.

Has 60psi fuel pressure at idle and no load wot, wot or slight throttle while driving it barley maintains 25 psi flutters between 0-25 until you stop.

What he has replaced so far
new mechanical fuel pump( tried 3 so far)
new ford motor craft fuel bowl assembly
New fuel filter and fuel lines
Injectors where replaced with new alliant power( stock) 2 years ago


I dropped the tanks, cleaned them and put new pick up screens in them, pulled the lines and blew them out.

New injector orings

Also swapped in a good selector valve from another truck.

Does seem to smoke alittle bit when it starts to struggle ( blackish gray)


The chip is off the pcm

I've checked all the fuel lines over for leaks.

No codes and all the data values look normal

Hpo system is good

Could this be a head issue?

injector cups look fine no fuel in coolant or oil in fuel.


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Bypass the quick disconnects that are between the pump and tank.
They have orings in them that can wear out. It'll suck in air, but won't leak fuel out.

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obs addiction
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Discussion Starter #3
Interesting, i will do that.

Thanks 79jasper.

If it is the quick disconnects are replacements still available?


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PSN intsigator
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I replaced mine with rubber hose and clamps.

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You should be able to replace the O-rings in the quick-connects using the proper disconnect tool (I would think). Cheers!
 

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The disconnect tool has nothing to do with the actual orings.
Yes, you can replace the orings. Or you can replace the disconnect itself.
Or like heavydoc said, do away with them.

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You still need to use the tool to disconnect them thus enabling the replacement of the O-rings was my point. Cheers!
 

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obs addiction
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Discussion Starter #8
So I bypassed every quick disconnect in the fuel system, runs a little better but still won't maintain fuel pressure under a load. It now flutters around 30psi when driving and about 65psi at idle/ neutral wot.

I'm gonna bypass the tanks and selector valve next to rule them out 100%


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The selector valve can possibly be the problem.

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obs addiction
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Discussion Starter #10
Bypassing the selector valve and tanks did not make any difference.


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obs addiction
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Discussion Starter #11
Figured it out, line was pinched under the turbo.


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Native Texan
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Wow that's one I haven't seen before. but glad you figured it out that would drive me bonkers.
 

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Administrator
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Thanks for the update.
 

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PSN intsigator
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Wow never saw one pinched that didn't leak. Hard lines are not very forgiving

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