Re: 7.3 Injection flush
Bio diesel will NOT clean!! My former employed made 300 gals a week and it was a maintenance nightmare..... filters and injectors suffered.
Kerosene not more that 10% in a single tank will clean. Good additives such as Power Service will also clean when used in higher dosage. I have also used ATF 16 ounces to a tank of fuel but no real measurable results.
If the engine is running okay I would use cleaner as above, change filters and keep clean respectable fuel in the tank.
The 7.3 injection system either works or it does not. The best way is to have the injectors removed, inspected and rebuilt if needed by a true diesel shop..... not a small car dealer.