Ok boys i got a new problem now. I put in new glow plugs and glow plug relay. made the truck start up on the cold mornings great so far.. now a new issue popped up. in the morning or even afternoon temperature doesnt seem to effect this problem... she will fire right up then sputter out and shut off then i gotta crank heck out of it to get it to fire up again. im kinda leaning toward air intrusion but where the heck would it be coming from. since i had it a week and half never had this issue this all happened in the last 2 days. Now to let you know what all i done. I did change fuel filter and vasolined the seal. i did also have to take the water seperator off the firewall and flush it all out so the pull ring would drop the fuel and water. i think i was carefull about putting it all back together and tightened all the lines good. i dont see any leaking fuel injector lines or any leaking fuel lines for that matter. Now once i fianally get her fired back up she run great doesnt happen while driving at all. just seems after a period of shut down it will fire right up instantly and just as quick stumble and die..... any ideas? oh yeah its a 7.3 idi automatic f-250

 

let it sit overnight and take the fuel filter off in the morning. If it aint full to the top then u have air gettin in.....

 

you might be onto something there. cause my son did say he unscrewed the bleed off cap and used his fingernail to depress the stem he thought he heard a hiss of air. now once we got it fired up we used a catch can and bled the valve off good till the foamy fuel was gone. hmmm now where do you suppose air could be coming in because that filter is before the injector pump and injector lines. would have to be coming in at the fuel pump or lines in right? maybe i aggravated a connection at the firewall fuel/water seperator? thanks

 

You have air intrusion, the most common place is the return lines.
The schrader valve.
The fuel heater (usually see signs of diesel here)
Uncommon places are
fuel line from filter to ip
the fuel pump itself.

 

You shouldn't have a firewall fuel water seperator on a 93.

 

Sorry i should be more clear the trucks actully an 87 f-250 was a 6.9 before me, it was changed to a 7.3 idi jasper motor. they just kept the old style firewall seperator and i still got the old style fuel filter too.

 

Ok what is the schrader valve and is it servicable? and is the fuel heater that gizmo on the passenger side at the front of the head kinda stands up vertically with a wire to it? they got her all taped up if it is.
Now i know what the fuel pump is. im gonna need to look tomorrow for signs of fuel leakage.
which begs another question will this problem be spotted by fuel leakage every time. thanks

 

Ok if you messed with I can almost guarantee it is where your air is coming from. Most of them were bypassed years ago. You can try to clamp a bolt in the hose but if it is letting air in at the shaft under the pull ring, it won't help.

 

Yep i did have it off the firewall and upside down to clean all the crud out it was so bad i could not drop the water out and she was all but full and i did unscrew the pull ring too. but i did vasoline it all up on install. you think that where shes coming in? can i just eliminate the thing by splicing in a steel fuel line? and what about future water problems will it collect in the filter then? thanks again

 

The fuel heater on a 6.9 is built in the fuel line between the pump and filter and will leak fuel if it was there.
The schrader valve is the valveon the fuelfilter that looks like a tire valve.
Air has smaller molecules than diesel so it will leak air in without letting diesel out, normally if the motor runs and pulls good the leak is in the return lines as it will suck air and starve for fuel if it is on the tank side of the fuel pump. I would bypass the water seperator first and eliminate that possibility.

 

Personally I have never had any problems with water, but I change my filter every other oil change too. There are several aftermarket water seperators that are good includeing at least one that bolts in the stock location and has a screw on filter with a drain valve.

 

My guess id you disturbed the return lines enough when you change the glow plugs that part of your problem is there.
Once hot fuel has been circulating through the return lines, the O rings get just hard enough that they don't reseal if you disturb the lines.

The stock water seperator is also very likely.

When the engine is not running, the fuel above the tank fuel level is held there by a vacuum.
If air leaks in, the vacuum is broken and the fuel returns to the tank.

If you have the water seperator pull ring working good, you might try just changing the O rings under the return line Tee's and the problem may stop.
But if it continues, either a bolt in the drain line or changing the water seperator out taking the stock setup out of the fuel line will most likely have you good to go again.