We figured out a while back if it started misfiring, drain the fuel heater/prefilter. Started that Wednesday, no help. Pulled the NAPA 3115 and spun on an FS1000. Truck ran like it's never run before. For 2 miles. Back to misfiring, and not clearing up. Cleaned the screen in the fuel heater (Donaldson) today and no change.

I don't like that truck.

 

What's going on with the weather where you are?

 

It was in the 40s or 50s and had howe's in the fuel.

Had a few days in the 60s and when the boss fired it up to go to the shop it misfired all the way in again.

Hopefully it'll be fixed when it comes back.

 

Ok, we had a t800 that sat for over a year with 1/4 full tanks. So every turn in the weather, it was sweating buckets in there. Ended up giving us fits til I got the whole story. Drained the tanks, heated them to boil off any residual water, then new fuel and filters, no more problem.

Another thing to note, on an n14, there is no filter between the tank and the inlet check valve. So crud can get sucked into that valve, and cause all sorts of issues. Get a filter head mounted on the frame, that takes an fs1000, same as the engine, no more problems.

And... just ahead of the fuel tank, above the right step, there is a plastic shroud/wrap around the hoses, if the tanks are mid mounted. Under that wrap is a fitting, female to male, on both supply and return. I have seen this fitting come loose on the supply side, and cause headaches that would make a Billy goat puke.

Good luck

 

There's the screen in the fuel heater, and an fs1000 inside the frame. No filter on engine, unless it's some sort of flat cartridge deal.

 

The fuel pump burnt up in this truck this spring. They kept running it like that after I left.

Run 'er til she blows, then get mad at whoever is driving it. Glad I no longer work there.