As a fuel additive, Berryman B-12 Chemtool Fuel System Cleaner (part #0116) is not well-suited for use in diesel/compression ignition engines and can damage fuel pumps and fuel injectors and cause hard starting and rough idle. Instead, please use Berryman Diesel Injector Cleaner (part #0518) or Diesel Cetane Booster (part #0517), depending on your needs.