1. Bad Seals on Fuel Injection Pump Camshaft and/or the Drain Line from the Bottom of the Fuel Transfer Pump has a Restriction - If both seals on the fuel pump camshaft in the body for the fuel transfer pump and/or the drain line from the bottom of the fuel transfer pump has a restriction the fuel can leak by the seals directly into the engine. To correct, install new seals in the body for the fuel transfer pump and be sure the drain line is open.
2. Loose Fuel Injection Nozzle Nut(s) - A loose fuel injection nozzle nut or a bad O-ring seal on the nozzle inlet can cause fuel leakage. Tighten nozzle nut(s) to 30 ± 5 lb. ft. (40 ± 7 N·m) and check for a bad O-ring seal.
3. Bad Fuel Nozzle(s) - Check fuel nozzle(s) for cracks in inlet fitting, inlet line, or nozzle body. If you do not see a crack, start the engine and visually inspect each nozzle for leaks. Cracks in the inlet fitting and nozzle body are nozzle defects. Cracks in the inlet line are caused by the nozzle not being tightened correctly. Check for leakage at the fuel nozzle cap. If no leakage is seen the fuel nozzles can be removed and checked as per Testing and Adjusting section of this Service Manual.