6.9 not starting
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6.9 not starting
does anyone know if the mechanical fuel pump on the side of the block (1986 6.9 i.d.i diesel) will pump air if its gone bad? my brothers tank if full and the truck just does not want to start i seen that he had a bunch of air in his fuel filter and leaky return lines so i replaced them all and the trucks filter seems to be still filling with air
it started with the truck just being harder to start then it started to stall now it just wont start i ran a electric fuel pump into a gerry can and it seemed like it wanted to start but just was not quite doing it either
now i did tow the crap out of it to try and start it! it started for a little bit then died now it seems like it is not starting at all and i have cracked the lines etc.. the filter just seems to be still filling with air and now that the return lines are done i dont know where the air would be coming from both fuel tanks have the same result to so all i can think is lift pump because i dont see the injection pump filling the filter with air that seems backwards to me
it started with the truck just being harder to start then it started to stall now it just wont start i ran a electric fuel pump into a gerry can and it seemed like it wanted to start but just was not quite doing it either
now i did tow the crap out of it to try and start it! it started for a little bit then died now it seems like it is not starting at all and i have cracked the lines etc.. the filter just seems to be still filling with air and now that the return lines are done i dont know where the air would be coming from both fuel tanks have the same result to so all i can think is lift pump because i dont see the injection pump filling the filter with air that seems backwards to me
Senior User
Joined: Dec 2009
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The way I see it (I had the same problem on the side of the highway onetime...) if the filter is filling with air regardless of which tank is selected (providing that the selector valve is actually switching tanks...) than what is happening is you have a leak somewhere between the tank selector valve and the mechanical lift pump allowing the lift pump to suck air in and pump it into the filter (remember that air is less dense than fuel (or the air molecules are smaller than the fuel molecules..) so you can have air leaking in without fuel leaking out)
Does the truck still have the stock water separator mounted on the left side of the firewall (beside the brake booster)? If so, than that is the most likely spot for this to be happening. Try bypassing the water separator with a length of rubber hose, fill the filter, bleed the system (if required) and try starting the truck. Remember not to crank the starter too much... at least a minute of cooling for every 15-20 seconds of cranking.
Good luck
Does the truck still have the stock water separator mounted on the left side of the firewall (beside the brake booster)? If so, than that is the most likely spot for this to be happening. Try bypassing the water separator with a length of rubber hose, fill the filter, bleed the system (if required) and try starting the truck. Remember not to crank the starter too much... at least a minute of cooling for every 15-20 seconds of cranking.
Good luck
Methanoholic
Joined: Mar 2009
Posts: 6,442
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From: Maine (NorCal Native)
Yes. they can ...
How did you do the electric / jug test ???
1) Remove the suction line (rubber hose to frame hardline), connect a long rubber hose to suction side of pump to a jug of clean fuel ...
2) Remove the hardline from pump to filter, hook a line to the filter with an electric pump into a jug of clean fuel ...
-Enjoy
fh : )_~
How did you do the electric / jug test ???
1) Remove the suction line (rubber hose to frame hardline), connect a long rubber hose to suction side of pump to a jug of clean fuel ...
2) Remove the hardline from pump to filter, hook a line to the filter with an electric pump into a jug of clean fuel ...
-Enjoy
fh : )_~
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