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Random hard starts and air in return line????

gnel

gnel

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Location
Jalisco,Mexico
Two weeks ago I started the truck and it imediatly died and did not want to start. After unplugging and plugging in the pmd in the front bumper it reluctantly started. So I figured another bad pmd story. It ran fine for two weeks. Well yesterday after driving it a 1/2 hour away for a 2 hour lunch it wouldn´t start. So I lifted the hood and noticed my clear return lines were dry? So I ran the lift pump and started seeing fuel/bubbles and it finally started and ran fine all the way home. Today I checked the return lines first. They were full of fuel and it started right up.
So what could cause the return lines to randomly drain out? All the return lines are new and I can´t see or smell any fuel. I¨m learning as I go with this truck but am not much of a diesel mechanic. Thanks for any replys Gus
 
I would check to see if your LP check valve is holding. Not sure how off the top of my head but I'm sure someone else probably has an idea
 
Could be anywhere.
pinhole in a hose or fuel line,filter manager 0 rings getting bad,hose clamps not tight,LP fitting loose. intermittent leaking inj nozzle.
I would look at the 2 hoses at the bell housing and the filter to IP hose first for wet and/or loose,FM is a close second.
Sometimes a leak doesn't show under pressure.(bugger to find)
Have a looky see at the tank fittings also,wet there is a sure sign of trouble.

LP check valve leak back don't matter,pressure drains off after shut down anyway trough the return line.

Fuel system is closed loop.
 
Thanks for the quick replys. I will go inspect all the things mentioned above. Hey bison a quick question. If the pressure drains off after shutdown what (normally) keeps the fuel in the clear line?
 
gnel said:
Thanks for the quick replys. I will go inspect all the things mentioned above. Hey bison a quick question. If the pressure drains off after shutdown what (normally) keeps the fuel in the clear line?
Click to expand...

Lack of air entering the system. The return line is submerged in fuel in the fuel tank. So you have a air leak somewhere in the system to allow the fuel to drain out.
 
My 95 pickup was wet all along the frame rail before & after the LP. I cut the lines off at the top of the tank where the rubber transitions to metal inserted brass barbs & ran new (30r9 hope this is the right part #) bio rated hose from there all the way to LP to the FM and did the same for the return line from the block fitting. It was a PITA to do without dropping the tank laying on the driveway & I took a nice bath removing all the old chit. New lines & LP install cleared up all my issues. My old lines & LP were thin as a bear can especially at the frame connectors.

HTH's

Forgot to add my FM heater failed & that seal was also suspect, that was changed also...
 
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I hope that´s it since I haven´t found any thing else, but that would be too easy. Of course it hasn´t done it again since mon. I´ll keep searching. Thanks everybody g
 
OK another thing to check. I did the tank sock procedure about 13 mos. ago. Really don´t want to drop the tank again:nonod:. Thanks Bison g
 
mine does that. sudden stumble and stall that I usually avoid but when it does I bleed the air out of the top of the filter. wish and tighten quickly.
 
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