I've got this goofy situation going on and was hoping y'all could check my thinking.  

I'm working on a friends truck that started and died the other day. I get up there expecting to find a bad VP. Instead, I find there is no fuel getting to the lift pump. (Yes, it is a block mounted pump. 300k miles on it!) So I disconnect the suction line from the pump and blow into it. I can hear bubbles in the tank. Now, I pressurize the tank. Barely any fuel comes out.  I reconnect all lines, bump the starter, and blow into the tank as the pump is running to force prime it. No go. 

Should I be looking at a partially plugged line? Or partially plugged basket?  

Edited March 20, 20187 yr by trreed

Lines could be clogged for sure or lift pump is just shot. Could run brand new hose to the pump and fuel in bucket and that should tell you one way or another what’s goin on.

Any second pumps in the line? Early on there was a kit Dodge put out that put a second lift pump in the line. If the second pump is dead it may prevent fuel from flowing.

Screens clogged in the module?

I believe you're on the right track sadly that is no easy way to tell, like Mike suggested if there is another pump in line that's slowing flow down and there were occasions with plugged screens. Plus if it's all factory, lines are pretty restrictive. 

In my opinion chances are VP is probably shot or on the last leg after a treatment like that. If he's planning on keeping this truck I'd say new fuel system with a gauge obviously and possible new VP

Hard to describe. Dodge had a kit that allows a service tech to install a second Carter lift pump along the frame rail. Typically near the fuel tank. There would be a oil pressure switch and an extra power lead to the battery. I've seen a few variants of this but typically ends with the pump on the frame and most don't know it died or failed.

 

In the one case, I pull the pump off the block and the inlet pressure was so high that the check ball was forced from the outlet into the pump chamber and broke the hub plastic as the check jammed the rotor.

 

Needless to say, there is NO stock solution that is trustworthy. You best off getting an AirDog or FASS fuel system and replacing all of it. It been proven in the past that stock plumbing is too restrictive and stock lift pump just don't have the volume requirements. 

I'm really hoping I won't have to pull the basket.  Thinking I'm going to pressurize the tank with more than my breath today and see if there is any cracked lines.  Blowing into the tank last night I could get the pump to catch prime for a half a second but it wouldn't hold it.

And @Mopar1973Man, there wasn't an additional pump on the frame that I could see.

Edited March 20, 20187 yr by trreed

Pressurized the tank. 40 psi of air on top of the fuel mass was enough to push fuel to the pump.  Primed the system under pressure, got the truck running, and then no fuel pressure once the lift pump was on its own. So a Fass has been ordered. And I didn't have to drop the tank!!!

@trreed didn't you just sell one lol, never fails. 

I know!!!!!!!  Oh well.