Air Bleeding back in fuel system?

[PMalin]

I recently replaced my 2001.5's stock lift pump, with a lift pump relocation kit. Replaced filter, the cannister filled when I bumped the starter, etc.. Put the top back on it. Bumped starter several more times over a few days to cycle more fuel. Later had neighbor to help bleed injector lines. It fired up and began running again. Drove a few short trips. Let it sit 1 day and at startup had a "governor" response to rev it up and it settled b ack down. I think it had an air pocket feed through. It sat 2 days went and started it, it ran a few seconds and died. Crank, Crank, it didnt fire up. Suspecting need to bleed injectors again. Instead, I decided to pump the throttle 1/4 of the way while cranking and it sputtered and fired up. Began running smooth again. Drove it ok.
Was there a fuel check valve in the former stock pump setup, to prevent backward flow back into the tank while sitting, and would this still be in place with the Carter P4601HP ? Is there a likely other reason that would cause this? For the time being, I think I will bump the starter, wait 10 seconds and crank it while the lift pump is still running. Would like to know if this is common or what is the likely cause?

Thanks..

 

[Matt42]

Check the fuel return line for cracking and/or leaks. It can have a leak that will allow air in without actually leaking fuel. That's a definite problem point with the 12 valve engines, but it also gets reported with 1998.5 models.

 

[Ozymandias]

No check valve but it's a closed loop, so if you have air, there is a leak.

 

[BoeingDiesel]

Not sure about a 2001.5, but there is a return check valve on the IP and tee's off on the backside of the head. I've read comments that if the check valve on the IP is faulty it may allow the injectors to bleed down. just another item for the check list... Good luck.

 

[PMalin]

I just ordered a JIC 06 male both ends, "check valve". Gonna install it going into the filter canister where the JIC connectors are already there from the Vulcan relocation kit. Then will see if it still has this problem. Waiting on part to arrive.
On another note, how does the fuel return go back into the tank, does it just pour in at the top or does it have a tube going down into the fuel or what? If it just pours in at the top of the tank, then I dont see how it wouldnt be able to draw air if there is no checkvalve in the circuit. Since the supply line is larger than the return line and the elevation increases going up to the fuel filter, I think it would likely backflow if it can draw air from the return outlet inside the tank, unless a checkvalve is in place. This just seem to come about after the relocation kit install, and I feel pretty sure it's sealed and clamped good on fittings. ??

Thanks for the replies

 

[Ozymandias]

Tube goes all the way down into the tank.
You have a leak somewhere.

 

[BoeingDiesel]

Do you have a fuel pressure gauge?? If not I highly recommend you do so.
Look at this picture and does it look like your engine setup...note the areas circled in red.

 

[SmokinGator]

I've got a no start issue with fuel bleeding back as well and see some dampness around the return line connector below the tee going back to the fuel tank. Has anyone replaced that line with regular fuel hose or seen a kit to do it? I really dislike the plastic line and connector.

 

[PMalin]

Do you have a fuel pressure gauge?? If not I highly recommend you do so.
Look at this picture and does it look like your engine setup...note the areas circled in red.View attachment 131852

I recently installed a MaxTow 0-30 psi fuel pressure gauge. See around 6-9 psi now with the lift pump relocation kit installed with the Carter pump P4601HP installed down on the frame rail just ahead of the tank. I have cleared up my losing prime issue by installing a checkvalve. Not where I mentioned earlier, instead I installed it, too down near the frame rail, just ahead of the pump someplace. I lost 1 psi by doing the checkvalve install but now she cranks right up like it should with no fuss, even if sitting for a few days. The relocation kit just so happened to have 2 JIC 06 hose barb fittings that were necessary for the install, H'mm maybe for this purpose?? Anyway pretty happy with it right now. By the way, the diagram seems close but the fuel filter canister seems to be slightly different on my truck.

 

[SmokinGator]

Nice, what check valve did you use? And when you say " just ahead of the pump" do you mean between the pump and the tank? Thanks!

 

[PMalin]

Nice, what check valve did you use? And when you say " just ahead of the pump" do you mean between the pump and the tank? Thanks!

I installed the FUELAB 71702 it has the JIC 06 size fittings appx 3/8 inch line. The install of the checkvalve was between the relocated lift pump and the factory fuel filter up in the engine bay. in the fuel supply line, where fuel is going toward the engine.