I have an 86' 6.9 that ran great till yesterday then it died going down the road and now want run longer than 20 seconds any clue what could be causing this

 

What's your fuel level at? Anything close to 1/4 tank, put 5 gallons of fuel in it and see if it fixes the problem. If it does, then your in-tank fuel pickup "showerhead" has broken off.

 

One tank full and other less than qtr still same

 

Which tank were you using when it died?

 

Was using full tank

 

Had you just recently switched over to it? Or had it been running on it for a while? I'm beginning to suspect the tank switching valve stopped working on you and it's still pulling fuel from the 1/4 full tank.

 

Yes about 3 miles before started happening

 

Switch to the tank that's showing 1/4, put 5 gallons into it, and see what happens. 3 miles is almost exactly how far you'll go on the remaining fuel in the lines when a tank goes empty.

 

If that works do you think the 1/4 tank pickup has broke off or just ran empty cause I put 300 miles on one tank and the tank selector switch has went out possibly

 

sounds like it may be sucking air from a broken pickup tube in the tank. try hooking the lift pump to a fuel jug and see if it will run.

 

<<<@!1!@>>>

If it works, then your selector valve is bad. Also, since you ran out of fuel and still show about 1/4 tank, the "showerhead" on the bottom of the pickup is broken off. So you can't get all the fuel out of the tank. There are two fixes to this: one is to drop the tank (or pull the bed) and replace the showerhead, or the second is to make your own by getting a piece of fuel line, notching a "V" into the bottom of it, and then putting it on the pickup line without a clamp and pushing the pickup down into it's place. That should make the bottom of the tank push the fuel line up on the pickup tube so it's just high enough to reach down to the bottom of the tank. Then pull the pickup back out, put a clamp on the hose, and re-install everything.

Myself, I prefer the showerheads. They're easier to do and only cost about $30.

 

I do have 2 injectors leaking around top of return sleeve could that be part of the problem with the system not holding prime and my fuel gauge doesn't work

 

Leaking injectors won't stop it from running. They will stop you from holding a prime when you shut the engine off, and make it take longer to start back up again. Your problem isn't in your injection system, it's in the fuel delivery system.

 

Did the gauge respond when you switched tanks?

 

No gauge hasn't worked in 2 or 3 weeks and now this does the gauge work off selector valve cause neither tank does the gauge work on