Contaminants In Fuel Diagnosis: Description

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Fungi and other microorganisms can survive and multiply in diesel fuel if water is present. The fungi can be present in any part of the fuel handling system. These fungi grow into long strings and will form into large globules. The growths appear slimy and are usually Black, Green or Brown. The fungi may grow anywhere in the fuel, but are most plentiful where diesel fuel and water meet. As fuel is agitated, when service station tanks are being filled, fungi are distributed throughout the tank and may be pumped into a vehicle.

CAUTION: Avoid physical contact with the biocides in order to avoid personal injury.

If fungi have caused fuel system contamination, use a diesel fuel biocide to sterilize the fuel system. Do not exceed the dosage recommended. Discontinue use of a biocide when towing a trailer. It is permissible to have biocide in fuel when starting to tow, but do not add any biocide while towing.

Steam cleaning may be necessary if most of the fungus growth cannot be removed with biocides. The presence of water or gasoline in diesel fuel may also cause injection pump and fuel injector damage.

This procedure checks for the presence of water and gasoline in diesel fuel that may cause fuel injection pump and fuel injector damage. Remove and inspect fuel filter. If water, gasoline or fungi/bacteria are not present, end the inspection. If water or fungi/bacteria are present, go to CLEANING WATER FROM FUEL SYSTEM in FUEL SYSTEM CLEANING . If gasoline is present, go to CLEANING GASOLINE FROM FUEL SYSTEM in FUEL SYSTEM CLEANING .