fuel pressure loss

[bohinc]

94 6.5 turbo diesel. Truck idols and drives down the road fine. Then randomly wants to cut out like its getting no fuel. Crack the bleeder and abunch of air comes out. So I looked under the truck and the return line was leaking so I replaced the part that was leaking and it still wants to cut out. i dont know where I should look now. Is there any commen problems like this?

[a5150nut]

If your getting lots of air you probably have a suction line leaking. IIRC most common place is over the top of the tank. Check from fuel pump back to tank.

[bohinc]

Alright ill check that then. Thank you. I know I use to get vacuum when I would unscrew the fuel cap to put fuel in the truck. But about this time last year I quit getting the vacuum but did think nothing off it. It didn't start acting up till amonth ago

[Robyn]

Does it make a difference if the tank is full or less than half ???

There is a suction relief valve in the pickup tube that is there to allow fuel in even if the sock is plugged.

These will allow air in if the tank gets below about 3/8 full.

Just a thought.

[bohinc]

Its at 3/4 of a tank. And I haven't drove it much since then because I dont wanna take the chance of getting stuck anywere. Thank you for the inpu. Learned something I didn't know

[56pan]

Does it make a difference if the tank is full or less than half ???

There is a suction relief valve in the pickup tube that is there to allow fuel in even if the sock is plugged.

These will allow air in if the tank gets below about 3/8 full.

Just a thought.

I've got nothing to add to help with the problem, but I'm impressed with that little bit of arcane knowledge and thanks.

[DaveNY]

Just finished up with same problem, thought it was sending unit and dropped the tank. Both lines separated where the flexable rubber joins the steel. I had a stumble and occasional miss at first when pulling out of the driveway. After a few weeks It ran like a big block with a cracked distributor cap. Changed the tank sender and rear lines, All Gone.
Found a couple of pinholes in the tank.

Dave

[phantom309]

With it idling crack the bleeder see if the motor keeps idling,. if it quits then the lift pump is nfg.

Does it cough and splutter when its stalling,. or just shuts off and doesn;t want to fire at all?

check PMD troubles with 6.5 's
Return line leaking won't cause any driveability issues,. just murder on fuel economy,.