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Old 01-14-2013, 05:02 PM   #1 (permalink)
Jace
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Another weird fuel return issue

Installed new injectors and return lines. Bled the air out and started the truck. I got it to idle and I noticed fuel pouring out at the passenger rear injector (closest to firewall). It appeared that fuel was leaking at the return line. One of the return nozzles is capped off and the other one goes to the injector the right of it. The truck started to stumble and want to die which I assumed was from the fuel leak. Weird part is, if I pull the return line off the injector (the line that is connected to the next injector) the truck returns to normal idle. Obviously there is still fuel leaking out of the now disconnected return line, but the the truck idles fine. While e truck was still idling, I hooked the return line back up to the injector and the truck starts to idle rough and die. I'm clueless of course at what is causing this, any ideas?
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Old 01-14-2013, 05:24 PM   #2 (permalink)
ADAMSK20
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u had a earier post with return line probs right? , have u checked the main return line that goes back to the fuel tanks( it also routes thru the tank selector switch) ? sounds like u have a blockage in that line, excess return psi can cause the ip to do strange things, take the caps off and blow back to the tanks u should have little to no pressure in that line when blowing air.
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Old 01-14-2013, 05:31 PM   #3 (permalink)
ADAMSK20
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one other question when u hooked it back up and it started to run rough was it blowing black smoke out the tail pipes, if it was thats another indication that u have a restricted return line.
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Old 01-14-2013, 05:37 PM   #4 (permalink)
Jace
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When I hooked it back up it was blowing white smoke. I had issues with the previous injectors, 2 return nozzles fell out of two separate injectors. I installed all new Delphi injectors.
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Old 01-14-2013, 05:43 PM   #5 (permalink)
ADAMSK20
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check the main return lines to the tanks, i bet u have a restriction. or someone has the return lines on the selector valve in the wrong ports.
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Old 01-14-2013, 05:44 PM   #6 (permalink)
ADAMSK20
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was this truck running good before u started working on it? or is it strait off the army surplus line?

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Old 01-14-2013, 07:12 PM   #7 (permalink)
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Quote:
Originally Posted by ADAMSK20 View Post
was this truck running good before u started working on it? or is it strait off the army surplus line?
It was running good until the injection pump stopped working . I replaced the injection pump,injectors, spin on fuel filter mod, installed electric fuel pump and bypassed the mechanical pump.
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Old 01-14-2013, 07:13 PM   #8 (permalink)
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All the other injectors have their return lines hooked up and it idles fine? Hook up the one with the cap and it dies? Hmmm I agree, start with the main return and see if it's obstructed. Maybe you just have enough flow for 6 injectors and attaching the other 2 cause a backflow.
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Old 01-14-2013, 07:17 PM   #9 (permalink)
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And just for future reference, the fuel really does squirt out of the injector returns. The return opening is so small that while not high pressure it isn't low pressure. It probably shoots 1" rather than dribble
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Old 01-14-2013, 07:47 PM   #10 (permalink)
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Yes all the other return lines are hooked up. I noticed also that if stuck my finger over the return line and kept the fuel from coming out, the truck would die. If I just left the return line disconnected with diesel pouring out everywhere it ran fine.
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