Need to bleed off air!?!?!?! - Diesel Forum

RockinDW · 10-31-2009, 12:59 PM

I recently changed out the injection pump, the fuel pump, and most of the fuel lines on my '83 6.9L diesel. is there a simple way to get the air out of the lines? i have had it started. it will run any where from a second to 30 seconds and sometimes longer then it dies. is this an air in the lines problem or possibly a timing problem? Also when it is running the throttle has little to no reaction. occasionally it will rev up a like its supposed to but u have to flutter the pedal to get it to do anything. any tips or advice would be much appreciated.
thanks

Evel486 · 10-31-2009, 01:05 PM

You have an air problem. Bleed the high pressure lines at the injectors. The filter should be full with no air at the schraeder valve. If you still have the stock water separator on the firewall, bypass it.

RockinDW · 11-01-2009, 10:39 AM

ya i already took out the stock water separator. i will see what i can do to get the air bled down. thanks for the info

InTheDogHouse · 11-02-2009, 01:20 PM

Hey Rockin,

From my limited experience, it DEFINITELY sounds like air in the lines. Just bought an 87 6.9L, played with the water sep (didn't know better!) before I drove it home 500 miles and had surging on the freeway with problems starting when I stopped to refuel. Had no idea what the problem was until I searched here where I found the ANSWER to your problems.

Bypass the stock water sep and buy a 7.3L fuel filter that already has a water sep built-in. A little more costly ($40 v $15), but sure sounds worth it. From what I've read, it should screw on just like the 6.9L filter. You WILL need a plastic bowl that screws onto the bottom of the filter. Bowl is $80 new from Ford, so I'm looking in the local junk yards first.

Njellison · 11-02-2009, 02:22 PM

Quote:

Originally Posted by DieselNewb

Hey Rockin,

From my limited experience, it DEFINITELY sounds like air in the lines. Just bought an 87 6.9L, played with the water sep (didn't know better!) before I drove it home 500 miles and had surging on the freeway with problems starting when I stopped to refuel. Had no idea what the problem was until I searched here where I found the ANSWER to your problems.

Bypass the stock water sep and buy a 7.3L fuel filter that already has a water sep built-in. A little more costly ($40 v $15), but sure sounds worth it. From what I've read, it should screw on just like the 6.9L filter. You WILL need a plastic bowl that screws onto the bottom of the filter. Bowl is $80 new from Ford, so I'm looking in the local junk yards first.

Good advice. A water seperator is needed and the newer design fixed the air leak problem of the old POS.

Are you still running the stock mechanical lift pump? They tend to suck air into the fuel lines through your connectors (and/or the old water seperator). Try installing an electric lift pump back by the fuel tanks if the new seperator does not fix your problem and that should help eliminate most air leaks as you will then be pushing fuel instead of sucking it through the majority of your fuel lines. Then you can just inspect the lines and see if any wet spots develop which is where your air leak was. Good luck.

jray3 · 11-04-2009, 12:27 PM

Does the 7.3 style fuel filter/water sep. also provide the "water in fuel" indicator signal? My '87 still has the original setup working correctly, except for plugging the drain hose to prevent air intake.
Thanks,
Jay