So me being the idiot that I am accidentally ran my 6.9 idi out of fuel. So I get my dad to tow the truck home, fill it full of fuel, crack all the lines and bleed air out of the system. I eventually got it running but noticed that the fuel was somewhat cloudy and appeared to be contaminated, there was a white liquid floating around in the diesel that had separated from it

so the truck idles fine, but when I try to start it now it runs like it has air in the system for a few seconds then clears itself up. But whenever I rev the engine it dies like its not getting enough fuel.

could the govenor inside the pump possibly be sticking since it ran out of fuel? Or maybe did it suck some crap into the filter and partially plug it off? I replaced the fuel filter about two weeks ago as well, I also heard that I could try filling the filter with ATF to help free up the govenor if it is sticking. Just looking for any other advice.

oh also the return lines are leaking once again from the caps since bleeding the high pressure lines so the return lines will be getting replaced again if anyone has a recommendation for what brand I should pick I’d really appreciate it

 

draw some fuel out and let it sit and separate. is it water in the bottom?
the governor will not stick from running out of fuel.

 

Definitely try the old ATF trick. Fill your fuel filter with ATF, then start the truck and let it run for 30 seconds or so. Shut it off and let it sit overnight before starting it again. This will let the ATF detergents work on the inside of the IP and injectors. I suppose you could do the same with SeaFoam or Lucas, but ATF is scientifically proven to cause an IDI to "chatter" less.

 

Ok that’s good to hear I was really worried I damaged the pump, and yeah when I get home today I’m definitely gonna try that trick on my truck. I’ll throw a new fuel filter on as well, or would I be able to just drain the old one and fill it with atf since it’s a brand new filter anyways?

 

I suppose you don't have to replace the fuel filter. It's just one of those MAW things.

 

Well I just got around to taking the fuel filter off (which I just recently replaced) it is full of water and other garbage it sucked up from the tank

is there any chance I haven’t ruined the injection pump? I’m getting a new fuel filter and I’m gonna fill it with ATF and let it sit overnight, hopefully that will work

 

Well the fuel filter is supposed to protect the injection pump by blocking junk. Granted if it was a whole lot of water, some certainly could get into the injection pump, but I don't think it would be ruined with a short exposure to water (I may be wrong though).
HOWEVER, running out of fuel will not suck the water and garbage out of the bottom of the tank. The fuel pickup sits at the bottom of the tank and always draws from the very bottom, meaning it would ALWAYS be drawing any water or garbage that was down there. What did you use to fill the tank? Do you have any enemies that would have dumped stuff in your truck? Something isn't adding up.

Depending on the quality of the lines and plastic caps that you have for the return lines, you might be able to just replace the o-rings under the caps. Using Viton o-rings and plenty of lube usually works well. I think the proper size for the o-rings is 111.

One thing I'm not sure of, is if water did get into the injection pump, would it work its way out into the fuel return system, or sit in the bottom of the pump trapped there. You may have to pull it out and drain it somehow.

Also you should drain and clean out your fuel tanks. You might get luck with using the water drain at the bottom of the fuel filter, but if a lot got in there, you'll need to drain it all and start clean.

 

I was wondering that too, my truck has two fuel tanks (selector valve still works too) and it was the front tank I ran out of fuel. I last used that tank about two weeks ago and the truck ran fine with it, about a day later I changed the fuel filter and everything looked good. No water, debris, or any other type of contamination

Today I switched over to the rear tank which I recently filled with fresh fuel, and flushed all of the nasty fuel out of the filter head and lines (replaced filter too) once it looked clean I cracked all the lines open and flushed all the dirty fuel out of there too, hopefully cleaning out the injection pump as well.

I then removed the filter again, filled it with ATF, ran the truck for about 30-45 seconds, shut it off and am letting it sit overnight. I will update on how it went tomorrow

 

me thinks the jug used to add fuel to the front tank was not clean and had crap in it.
drop the front tank and clean it out before refilling it.
the water will not hurt the injector pump if only run through for a day or so.. it WILL hurt the engine if enough got in there, but luckily the injectors will not pump enough in to hydro-lock the engine

 

Well I found the problem, the gas cap on the front tank isn’t sealing properly. It rained and let water into the tank causing my problem, running it low on fuel only caused it to suck more water up. Most of it got caught in the fuel filter but some made it into the injection pump causing the govenor to stick which is why it dies when I let off the throttle. Like I said I flushed the fuel out and have clean diesel in the rear tank, added some ATF to the fuel filter, ran it about 30 seconds or so and I’ll see how it runs later today when I get home from work. Really hoping it’ll free itself up after soaking in the ATF overnight, don’t feel like spending the money on replacing the injection pump

 

Hope she decides to run well with the old ATF trick.🤞

 

I'll say it again, the stock pickup pulls from the very bottom of the tank. Diesel floats on water, so any water sinks to the bottom of the tank. It will suck up ANY water that get into the tank immediately! If the amount of water in the tank is more than the filter can hold, it will get passed onto the injection pump. Running low on fuel has no affect here. If you have a full tank of fuel, and water gets into it, the next time the engine runs it will suck that water up.

If the fuel pickup is broken off, it won't reach all the way to the bottom, but will suck whatever is at the level of the pickup. That is a common issue with these trucks where they run out at 1/4 of a tank.

 

So I tried the atf trick, took it for a 25 or so minute drive and it seemed to be running better. It wasn’t perfect but it was definitely driveable.

I then took the small triangular plate off the side of the injection pump to drain any water out of it that settled to the bottom now it is running worse than before.

I took the filter off again and it looked like the atf hadn’t have even been sucked into the fuel system. It all just settled at the bottom of the filter. I added some diesel kleen and atf to it again and I’m letting it sit for now hopefully this helps

 

Probably you need to bleed the fuel filter and the injectors. With the engine cold, use a screwdriver and depress the schraeder valve on the fuel filter. Have a buddy crank over the engine and you should get a solid stream of fuel.

After doing that you can bleed each injector by loosening the fuel line nut at the injector and cranking the engine. Make sure you wear safety glasses as the fuel lines will spit fuel. You can even loosen the fuel line nuts individually with the engine running. If loosening the fuel line nut doesn't change the idle quality you know that injector is suspect.

 

You can purchase the Viton "O" Rings from McMaster-Carr in bags of 50 for around $10,
size 111. Always good to have a couple bags on hand.


Charlie