1987 6.9 diesel stalls after start and is then hard to start

[Ford Guy]

I have a 1987 6.9 diesel, that if you leave sitting over night when you go to start it, it cranks and fires, and feels like it starts but after a few seconds of running stalls and dies, and then it is extremely hard to start. I am sure it is air in the lines somewhere but what i need help with is trying to figure out where it is getting air at. The return caps are slightly leaky and there appears to be diesel in the valley pan, non related leak to the return caps. any ideas where the air might be intruding at, or possibly any other ideas as to what could cause this to happen? its got me stumped and it usually only does it after the engine has cooled and sets for at least 18 hours. Its got me stumped, any help would be greatly appreciated.

 

[IDIDieselJohn]

Yup, that sounds like the classic air intrusion in the return lines, especially if you say yours leak.

 

[bigtex]

mite be worth a look, but check all the fuel line connectors from the pump to the injectors, then from the inject. pump to the lift pump. try working back to the tank.

 

[subway]

i believe that you answered your own question in your post. if the return caps are wet they are leaking, and it is easier for air to be pulled in than diesel to leak out. order a new return like kit or replace the o-rings at the least to get you by.

 

[Wyreth]

Also check to make sure the return line off the IP is tight, and dry. (that was my worst leak, and it was just a flick of the wrench to fix)

 

[CurtIDI94turbo]

Also you may want to take a look at the supply line to the IP. The gaskets... Olives... may be bad.

 

[DuRolf]

I just had exactly the same symptoms start on my 1985 6.9 IDI after having the vacuum lines worked on. My C6 went south, and in the process of having a remanufactured transmission installed discovered the vacuum line had at some point in the past been routed past the vacuum switch and sent straight to the pump. Now after a rough start the engine stalls and then it takes some time to get it going. Once it starts up again it runs fairly smoothly.

 

[87 idi]

i had this problem and I replaced all my glo plugs and it hasnt done it since.

 

[GOOSE]

Pressure wash your engine, you want it clean for two reasons, to find the leak and to make the repair easier. I agree, you have your hands on the answer, the return lines. Russ, Typ4, sells a good set at a great price and is really good to deal with. The olives are also good maintenance while you have the aroma of diesel on your hands. Good luck