rough start

[Ncgomez65]

I need some help with figuring out why my truck starts very rough. I have a 86 f250 6.9l. I develope a leak from the filter to the injector pump. I tighten that and had no problems, but about a 2 months later Started leaking again. So I tighten it and a few days later it started to run very rough once I started it. After a minute or 2 it went away. I have already changed the glow plugs and relay but it takes forever to start when it was cold. Had been using the block heater and it never give me any problems. I need to change the control.
I changed the return line and replace the the rubber seal in the line coming from the fuel filter. Ran fine when I was doing all the test drives and stopping and leting it sit for a few minutes. Then I drove and let it sit for 2 hours and then I went to start it and it started then died on me. Then It took 2 long cranks to get it to start. I had to drive it to work and it has been sitting for 8 hours and It will sit another 8 till Im off work. So I am wondering how it will start when I get off.
I also noticed that the fuel filter was almost empty when I took it off to check it. Im new to diesel truck so any help would be a lot of help

 

[lindstromjd]

Sounds like your lift pump is on it's way out if your filter is empty. Change it and see what happens. It's about a 1-2 hour job. Hardest part is getting the cam in the right position so the pump goes right in without having to fight it.

 

[damac]

Been there with my used and abused truck. I yanked the stock lift pump and bought the electrical carrier pump so many around here like.

Yanked out the inline fuel heater thing on the hard rail and changed to a simpler filter head without that heater plug.

I then installed some nice clear hose I got from mccaster carr that works real nice for fuel. Thick walled stuff that retains its shape.

Also there are "olive" seals at some unions on the fuel system like back at the return rail, hard rail to ip inlet, ip outlet. Those I just replaced due to the tight routing.

Then there is the return line kit.

But it doesn't stop there. You could have issues from the engine bay back. Near the tanks, selector valve, etc. Ours would leak so odds are it can suck air to.

We didn't have the luxury of pulling the beds and doing all the "right" things so the electric fuel is a patch job to a degree. Makes it awesome to prime filter and make sure you are getting fuel.

That way your first glowplug cycle will not be wasted and thats what can be happening to you with starting then stopping. Our truck did that and I used to get scared of getting stuck.

Put the electric pump on with a manual push button for the glowplugs and now with fresh batteries and starter I can hit the switch for 10 seconds and start the truck right up Completely different truck.

 

[Wyreth]

Went through all the issues you did. (including the re-occurring leak from input line on the IP) Fixxed all that, and a few days later, the air intrusion came back with a vengeance. It turned out to be the water separator. You might try bridging that, just to test, before you start spending money.

Mel did a good write up on the 6.9's water separator: http://www.oilburners.net/forums/showthread.php?t=18212&highlight=water

 

[Kevin 007]

Where is this heater on the hard line?

 

[Wyreth]

Where is this heater on the hard line?

I do not know if it is stock... but this is where my fuel heater is on my 87 6.9

 

[Ncgomez65]

After the truck sat for the 16 hours at work, I came out to find diesel leaking from the area of the water separator. So I took it to a diesel tech and he said to bypass the separator and see what happens. I did that and bleeded the air out again and have no more problems with the hard start. So now just have to get a new water separator. Thanks for all the help.

 

[GreenDiesel]

do some searching, there is a thread on here that details how to remove, clean and repair the OEM water seperator