Hi

After changing the lift pump I can not get any fuel into the pre/heater pre/filter I pressurized the tank and got fuel out of the return line but very little out of the source line to the pre/filter any ideas???

 

you can try pressurizing the fuel tank to help drive fuel up the line.. or pour a little fuel into the pump to help it prime!

 

I did that already also just so everyone knows the tank is over 3/4 full. Is the fuel supposed to run freely out the end of the fuel line when it is disconnected?
This one does not. I think this was my original problem as I have rechecked the old lift pump and it seems to be working.

 

I don't think you'll be able to force fuel thru the pump. Do you get fuel at the inlet to the pump? Have you ever changed out the rubber fuel lines? Did you replace the 90 degree hose between the pump and the prefilter? Did you remove the 10mm head bolt on top of the filter and attempt to manually pump fuel? Is it a known good filter?

 

Yes I do get fuel to the prefilter only when I pressurize the tank with air but very little flow not shooting out. No I have not changed the rubber lines yet. No I did not change that hose either but it did look ok. Yes to both questions. and the filter is new just changed it as I am doing this job. My question is weather the fuel should flow freely out of the fuel line at the pump or does it need to be sucked by the pump?

 

It does not gravity flow to the pump.

 

ok I thank you for your help

 

When you pressurize the tank fuel flows though both the feed and return lines. Backwards though the return.
If you pinch off the return with pliers while pressurizing the the tank and crank the engine at the same time engine should start.

 

Thanks I will try that

 

Hey
For anyone interested I got the truck up and running and all is well for the next while so thanks to all for the help and if I can return the favor I will.

yukondg