Fuel line leaking well what do you know.........keep us posted

 

will do! its leaking at the nut that threads into the pump... it wasnt sealing right. ive spent the past 2 weeks trying to get it to start reliably every time! if this doesnt fix it ill go crazy!

 

Let me just say this....if its leaking fuel, its more than a 90% chance its sucking air. Thats the reason why when you test things for leaks, you use a regulated air source. Air will find holes that liquids wouldn't think about coming thru.
In these older trucks, if in doubt, replace it. If a fuel line in hard, replace it. If its got dry cracks in it, replace it....
If you see a dry cracked rubber brake line going to your front brakes, you'll replace it, right? Do the same for the fuel lines....
Check valve in the return line is a +.
I replace all the mechanical lift pumps I can get with quality electric pumps. A busted diaphram will pump your crankcase full of diesel. Plus when old, you loose pressure.

A electric pump will prime your filter faster pressurizing your line with the switch being turned on, plus I wire them into a Hobbs Switch. You loose oil pressure, it kills your motor...simple, safe insurance.

 

Why?

 

A check valve in the return line should stop air from leaking back into the system if the return line is not submerged in the tank.

 

Hmmm, interesting. You know injector pop pressures run in the thousands of psi, right?

Have you ever seen an injector taken apart?

Good place for a check valve is about three inches BEFORE the VP inlet.

 

I used to work at a shop reworking pumps and injectors....25+ years....for diesel trucks and cars.

 

MMMMM my bad, I did not know the ONLY return line came from the injectors.
And yes I have had injectors apart, put back together and run.

 

Yea but not on a 1st gen Cummins apparently the only thing that causes a 1st gen to loose prime is the lift pump

 

So then, can you please explain how air can get into the system from the return side?