cant figure this one out

[genchowford]

92 navistar 7.3 converted to electric fuel pumps----hard hard start. put the clear line on just before the main filter to watch for bubbles--none being pumped up but when turned off big one appears as if draining back down in to tank. Does that mean air leak on the return lines? Or somewhere else. Thinking air is my problem. Just cant figure where its coming in. return line are fairly new.
thanks
fred

 

[icanfixall]

The air leak is probably the hard line from the fuel filter to the injection pump. The seals on that are called olives. They are flat o-rings. Any fuel injection repair shop can sell you the needed ones. At the rear drivers side of the motor there is a fuel return line. It has a 3 way fitting on it. There is an olive hidden in there too. Most owners never knew of this potential leak sourse. Replace and maybe your air leak will be solved.

 

[Agnem]

Sounds like you could easily divide and conquer to solve that. Take both the hard line and return line off the filter head. Plug both, then make sure your air is out via the schrader valve. Then shut off your pump and see if your bubble is there. Reconnect the other 2 lines one at a time, purging air, then checking as before.

 

[genchowford]

The air leak is probably the hard line from the fuel filter to the injection pump. The seals on that are called olives. They are flat o-rings. Any fuel injection repair shop can sell you the needed ones. At the rear drivers side of the motor there is a fuel return line. It has a 3 way fitting on it. There is an olive hidden in there too. Most owners never knew of this potential leak sourse. Replace and maybe your air leak will be solved.

correctamundo icanfixall, it was the olive on the hardline to the ip, thanks also to agnem, thanks verymuch guys.