I have a 1993 Ford F250 Extend Cab 7.3 Turbo Diesel 5-Speed and I recently modified it to allow access to the forward tank. I bought it used with 270k miles on it and I have no idea when the forward tank was last used. The previous owner installed a long bed that didn't have a place to fill it with fuel. I installed a filler neck for it, put in about 6 gallons of diesel in the forward tank used the auxiliary tank switch and all seemed well for about a week. Then the engine started running rough and within a few minutes it shutoff. I assumed I must have run the forward tank out of diesel and went on my merry way. It ran fine for about 2 miles then the engine started running rough again and quit within a few minutes. I assumed the switch must not have worked and switched the setting back to the forward. It wouldnt start. I then ran to the station and filled up about 6 gallons of diesel and put approximately 3 gallons in each tank just to make sure. The truck will still not start. It turns over but doesnt fire at all. The switch doesnt seem to have any affect since the fuel gauge doesnt reflect any change when I switch from one tank to the other. I know there is fuel in both tanks but she still wont start. Does anyone have any recommendations on how I should first begin to narrow down what was affected by whatever was in the tank which led to the truck not running? Once again, I have no idea when the tank was last used but I have owned it for a year so I know its been that long. Thank you for your help.

 

If you ran it dry of diesel, you can't just put some in and go--you have to prime the system. Plus, you may have had water (from condensation) enter the system from the front tank, or you clogged a fuel filter somewhere.

Jason

 

+1
the new diesel probably loosened up whatever jelled diesel sludge that had been sitting in the bottom of the unused tank. Hopefully it's just a clogged filter and not a ruined injector(s). Start with the filter and maybe drop the front tank to clean it out?

 

We did replace the filter and we did prime it. We have been working on it now for the last couple of hours and we can get it to start once we prime it but within a couple of minutes it dies. Is it possible that the auxiliary fuel switch unit can cause this problem? We did not find any water or sludge in the fuel filter as we have cycled it through several times now. Is there a way to determine if the problem is the unit that switches between tanks versus the condition of the tank and sending unit within? Another clue to the issue is when it does die out the fuel filter is only half full when we pull it off to look. I have been running it off the rear tank for the last year so if there is some way to manually get the unit to go back to the rear tank that could do for now. Then I could drop the front tank when I have more time. Thank everyone very much for your help....

 

Whats the verdict???? TRUE OR FALSE

"Hi,
Probably going to be a bad fuel sender, usually the the rear tank is dependent on the front tank sender to work to send the fuel to the front tank to send it on to the engine, the rear tank only should transfer fuel to the front tank.

I'll take a look but yes it would be electrical. In this case it may be gauge or sender, possibly wiring or fuse. "