I just bought an 89 Ford f350 dually with the 7.3 to pull my 7000 pound travel trailer with and would like some info. I have a main daily driving gasser so this is used mainly for working and towing. I know without a turbo it's no speed demon but on decent grades it has hardly any pulling power at all. The truck has 121,000 miles and looks very good body wise and interior too. This first trip I had my combo weighed and came out to 15,550 pounds total. When I come up to a good size hill it just falls off fast and downshifts untill it ends up in second gear going about thirty miles an hour. The transmission does not seem to be slipping from what I can tell. Traveling on flat roads with the ac on top speed is pushing to reach 60 mph. Is this normal for these older diesels or do I have problems? I have a big family and sure like the size of this truck to haul the grill, coolers and other stuff for the kids while riding comfortably. I don't think there's any way this truck will tow this camper up a mountain pass as the smaller hills have the accelerator to the floor now. Any info sure would be appreciated.

 

Your right...

The Non Turbo 6.9/7.3 is a bit underpowered in comparision to the Turbo'd/PSD's for pulling the weight that you are.. There are 2 main ways to build power with a diesel, and that is add more fuel, and air.. If you were to turbo your 7.3, then you can turn up the injection pump higher to build more power with 'both' improvements.. You don't seem to have any running issues other than lack of enough power.. Has the injection pump been changed? Should of by now at that vintage/miles, but that would be an area of concern for me at 120K if you feel that your under OEM output.. (if it hasn't).. You can as a first attempt, turn the injection pump up slightly for a 'bit' more power, but if you add to much fuel, it may black smoke some, EGT can rise some, and your mileage will suffer some as well from the addition of extra fuel.. 'Clean' unabstructed intake as well will help...

.....................HP................