[VD350]

Ok the last week something changed. I'll just talk about my issues this morning.

Ok plugged the truck in over night (because of the issue i'm explaining) thinking that when I started it up it would load up (being as I would hit the gas as soon as it started and send it into cold idle). Well i go out this morning, unplug the heater, and let the glow plug light go out. I hit the key and as soon as it turns over she pops off. Runs beautiful for about 5 seconds, then surges for a few seconds, and shuts off. I have to crank it for about 15 seconds, pumping the crap out of it for it to start again and it will never have that problem again for the whole day. I spend 8hr in school, come outside and it will start on the first turn of the engine. ***?

I originally thought that maybe I wasnt stopping completely on diesel but when I switched to diesel I ran it 16 miles and it smelled like diesel when I shut down.

Next thing that came to mind was maybe the fuel filter is dirty but its not lacking any power or surging going up the long grades here in PA.

Any Ideas? BTW every part of my fuel system (IP, injectors, lines, everything) is stock.

 

[sle2115]

First of all, you are going to get dinged for saying you hit the "gas" on a diesel truck! /ubbthreads/images/graemlins/smile.gif

I still think it has to be air. Sounds just like every complaint I have heard that turns out to be air.

So, some questions:

Are you still using the stock water separator?

Did you replace or have the return lines and t's replaced? (sounds like a return line leak)

I am assuming you don't see fuel anywhere, but look real close. These things can leak air but not fuel, so it is hard to find. Sometimes, if the T's have been replaced, they didn't get seated properly. Might want to check them all and try to push them down firmly.

Good luck!

 

[cself002]

Have to agree with the air diagnosis...

Try having a buddy do the first crank in the am while you stand ready at the schraeder valve. As soon as it starts press in the valve and watch the air come out. I just went through this and found once it was started after releasing the air in the am it would run fine all day. Without fail the next am I would have the same problem. Finally just replaced my supply and return lines and the rear tank. Runs great now....knock knock. For lines, I found autozone has lines that (while not viton) say they will hold up to methanol if you happen to run bio with veggie. Best of luck.

 

[VD350]

Should have mensioned this but the Water separator has been bypassed on this truck before i got it

Thanks we'll try it tomorrow morning

 

[DevoK12RS]

air X 3

 

[VD350]

Pushed the valves and fuel comes out. Doesnt seem to be the problem

 

[arthurgoboom]

I've been watching you post here with issues like this for some time now. Have you tried putting clear tubing in place of all of the rubber return lines? After installing them you observe the lines, this allows you to see any air bubbles entering the system and locate the source. It's the only foolproof way to check for air intrusions, especially on problem vehicles such as yours. 6.9 should have 3/16" return line nipples, so go to a hardware store and get like 10 feet of clear vinyl 3/16" ID tubing and put that stuff in place of your rubber return hoses. It will last plenty long enough for you to diagnose the problems (I'd say a month would be no problem).

What you're looking for is air bubbles creeping in after you shut the engine off. It most likely will take quite some time, as you said it'll sit for 8 hours and fire up, but then overnight (~12 hours) causes the stall. Put the lines on, get it reprimed and observe the fuel flow when the engine is running, then go to school. When you get out of class, pop the hood and look at the lines, see if any of the lines are empty.

 

[VD350]

ok sounds like a plan, I'll probably grab some monday. So your thinking the air may be comming from the cylinders, going through the return lines, and going into the filter?

Another though my buddy had was maybe the rubber O-rings on the injectors may be going bad. Think this would cause my sympoms

 

[arthurgoboom]

The problem is that the air seeps in and lets the fuel drain away through the return lines and go back to the tank. It's like if you stick a straw in a full glass and cover the top, then pull the straw out. The fluid stays in the straw as long as air doesn't leak in. The air leaking in lets the fuel run down, and since the return lines connect to the steel line that feeds into the IP, it drains the fuel out of the lines and off of the top of the filter head and that line. It starts on the fuel left in the injection pump, then gets a big slug of air and dies.

O-rings on the injectors bad would cause the same symptom. It's either those, or some of the plastic caps that go on top of those O-rings are cracked, or some of the rubber return hose is cracked somewhere. The symptoms of start, run a few seconds, then stall are what everyone else has described when they had an air leak in the return line system.

 

[VD350]

ok, definatly makes sence.

 

[VD350]

Ok a little quirk in its usual behavior.

Ran it friday night over to my buddy's house. Saturday night I started it up and had the same issue. Tonight I started it up and it didnt surge or anything, started and ran great. is it possible do you think that it could only leak air under certain conditions?

 

[DevoK12RS]

Nose up or nose down can make a difference- I've read.

 

[VD350]

its on level ground every night. Started right up this morning too

 

[arthurgoboom]

Is this with the clear vinyl lines on the engine, or are the original rubbers still in place? If it is starting fine now with clear vinyl line, I would say that the hoses were at least part of your problem.

 

[VD350]

nope still with the stock lines.