Fuel Injection System

Before suspecting the fuel injection system as a possible source of engine trouble, other engine systems should be checked. The exhaust system should not be restricted, the fuel supply system should supply an adequate amount of clean fuel to the injection pump, and the air intake system should not be restricted. If after checking the other systems and making the necessary repairs a problem still exists, perform the following test:

1. Check fuel lines to injectors for kinks or restrictions. Repair as necessary.
2. Run the engine at the RPM where the problem was most pronounced.
3. Momentarily loosen (1/2-1 turn) the fuel line on 1 injector. Then tighten fuel line to specification.
4. Repeat step 2 for each cylinder.
5. If 1 or more nozzles are found where loosening the fuel line makes no difference in operation, that nozzle should be removed and tested.