I drive a 1987 f250 XL 6.9 IDI. I went mudding and got back into town, and heard my fuel tank fall off. My truck died and I replaced the tank, fuel line, pump works and fuel filter is clean. The output of fuel filter flows. I see bubbles in my fuel lines coming from my tank. Engine cranks, spark is good and so is engine compression. Fuel is my problem.

 

I need help with a diagnosis

 

Dude. First off, sweet handle.

I'm chuckling right now.

Next, you went mudding and you "heard your fuel tank fall off." LMAO. That must be some serious freak'n mudd'n.

I'm not sure how you can see bubbles, unless you are running clear hose. Or do you have a temporary clear fuel filter or sight glass?

These don't have spark. Do you mean your glowplugs are functioning?

I'd say it's safe to assume that you don't have an immediate compression issue from a decent session of "mudding," but since you somehow lost a fuel tank in the process, I can't say for sure.

I'd have to ask first if you purged the air out of your injector lines. Since you ran it dry, the IP can empty and air can be lodged in the injector lines. This absorbs the injector pressure so that it can never "pop," thus it'll just keep cranking. You'll need to crack at least four injector lines and wait for the diesel to squirt out as you crank. As they spurt, tighten them down, and you'll work your air out of the lines. Eventually it start to sputter and after four lines are purged, you should be able to crank it and get it started. Rev it a bit so that you can get the other non-cracked injector lines air worked out.

If you crack injector lines and no fuel comes out, you could have a bad IP, or stuck metering valve in the IP, since you said your fuel filter schrader is flowing fuel.

 

Yea it was a pretty crazy session, enough to drop and rip a hole in my tank. The blots came loose and the support bars dropped. Im running a clear hose as my fuel line running up to my mechanical fuel pump. How much should I crack the injectiors? And yes I mean that my glow plugs are functioning correctly.

 

Cracking is basically just unscrewing your injector lines a few threads. just enough to let air and diesel dribble out, but not so far that you are fumbling to get them back to tight.

If you want, you can undo the injector line at the injector completely on one line, just to see if any fuel is coming out at all. I put a small plastic pill bottle or baby food jar under it to catch. If after a few decent cranks you don't see any fuel, you might have an IP problem, or clogged injector line, or closed FSS, or lift pump problem, or shut metering IP valve.

ALso, don't crank for too long. Only like 10-20 seconds with the pedal to the floor. Then let the starter rest for a few minutes. It helps A LOT if you have a battery charger set to "crank" because these engines like to have a strong current to get started.

Come to think of it, maybe your problem ain't fuel related, but battery related. How strong are your batteries?

 

I just had one recharged and it puts out a little over 12V and I replaced the other on Sunday. Should there be a constant flow of fuel while cranking, coming from the fuel filter? This used to be my daily driver but after this incident I'm stuck driving a sedan and it just doesn't feel right. I need to get this thing running, it was running amazing before the whole mudding fiasco.

 

It should be flowing (maybe slightly spraying) out of the schrader valve. If it's sputtering air, then you still have too much air in your fuel lines. Crank out all the air first with the lift pump by cranking and holding the schrader valve. If it doesn't clear up within a minute, then you have air getting in the fuel lines behind the lift pump. I know it's a dumb question, but do you have a full tank? When you replaced the fuel tank, did you replace the "cone of failure" with a section of fuel hose?

My bets are on that you have air in the fuel lines. Hold the schrader valve and have someone crank the engine. Within a few dozen seconds, it should be flowing without air spurts.

Once the air is purged out of the diesel filter, then crack an injector line. Pull it off the injector completely and put a little jar underneath it. Then crank. If you don't get fuel dribbling out within ten-twenty seconds, your IP isn't getting fuel, or something is stuck.