It has been awhile since driving the truck, because the last time I drove it there were several things going on and I didn't trust it to get me anywhere. It had been running fine, then started running like it had an air leak. Then it would alternate between running normal, then like it was sucking air, and then it would bog down real bad. It was running like that all the way home and as I slowed down to pull in the driveway it died on me and I was halfway out in the street. Took along time cranking before it started again.

I am going to upgrade to a 7.3 fuel filter and water separator while I am messing with things and then maybe replace the lift pump.

What are all of your thoughts on the problem? I need to get this thing going.

Jeff

 

Sounds like its sucking air,check the fuel hoses from the water seperator where they connect to the metal lines.Common place for air leaks

 

I got rid of that thing years ago for just that reason.

 

How much fuel in the tank?

I agree it sounds like air or failed lift pump...

Check the lift pump at the Schrader valve on the Filter head, 1/3 pint in 10 seconds of cranking and it should pump up 5 to 7 PSI.

The stream should also be basically air free.

-Enjoy
fh : )_~

 

Smart move, It's a POS!

-Enjoy
fh : )_~

 

I don’t want to hijack this thread, but your situation seems like mine. My 86 6.9 has begun to die after driving a bit, when I stop and step on the clutch. It will restart immediately, or if I can manage it, it will restart if I let the clutch out. It may be air, but I’ve never had the problem and don’t recognize it. It runs great normally, and the lift pump is new. Is this problem unusual?

 

if fuel bowl is not full, you have a leak

vacuum leak is not fun since you cant use a leak detector

pressure the line and it will seal, will still suck air after this which stumps many

Need to go over every fitting to re seal and all sides of the line for rusty pin holes from tank to pump and verify fuel pressure after when running at idle an at WOT

 

Make sure every connection is tight and has no cracks, including both the rubber and metal fuel lines and their connectors. Even a tiny crack or a loose spot can let air get into the fuel system because of the suction from the lift pump. Also, the problem might sometimes be with the fuel tank itself. If there are any small leaks or cracks in the tank, air can get in, especially when the fuel level goes down, and air takes up the space left by the used fuel.

 

Take note: This thread did start back in 2010.

Ethanfoster, you are correct, air does replace the fuel used.
But that air won`t get into the fuel system.
How ever if the Shower head on the end of the suction tube falls
off, then around 1/4 tank it will suck air, and can leave you sitting
on the side of the road.

There could be a rust hole in the tube on top of the Fuel Sender.
The plastic fuel line quick couplers have "O" Rings inside, though
on my 86 have had them off and on a few times and never a problem.

There is the rubber 3/8" rubber hose to and from the Fuel Water
separator on the FW next to the Brake booster that probably never
been replaced, A pain to get to as well and the separator sucking
air. Not sure what years used this, my 86 had one. The 2 hoses were
connected together. I have installed a Racor 500FG Filter/Separator
with 2 Micron filter.

There is the short 3/8" rubber hose at the Lift Pump. Sometimes called
the curly "Q" hose.
The steel line from lift Pump to Filter have seals on ea end called Olives.
If original, they are probably hard as plastic.
Also one on the metal line from Filter to IP.
The return hard line from IP to rear of engine (drivers side) I think has 2
also.
New one`s are available.
I replaced both with rubber hose.

https://www.ford-trucks.com/forums/1...ve-sleeve.html


Charlie

 

Sounds like the governor in the injection pump is sticking. If I understand what you're saying, you'll be driving along, approach a stop sign, hit the clutch. Engine dies instead of returning to an idle?
Pull the fuel filter, fill it with ATF and reinstall. Restart and let it run about 30 seconds, then turn off and sit overnight. See if improved in the morning, if not run another 30 seconds and sit. Should clear it up.