Preliminary Testing

Injection nozzle problems are usually accompanied by knocking in one or more cylinders, engine overheating, loss of power or performance, black exhaust smoke, and increased fuel consumption. To locate and correct faulty injectors, proceed as follows:

1. With the engine running at fast idle, loosen line unions on each injection nozzle one at a time. If engine speed remains constant with a line removed, that nozzle is defective.
2. To remove nozzle, detach injector line. Use special extra-deep socket (US 2775) to remove injection nozzles. To remove or install injector nozzles on turbo models, remachine a 1/2" (13mm) socket wrench extension to dimensions shown. See Fig 1 .
3. To disassemble, place upper part of nozzle in a vise and loosen lower part. Then reverse position of nozzle in vise and carefully remove internal parts from lower part of nozzle.
4. Do not interchange parts from one injector to another. When one injector is replaced, all other injectors must be tested and adjusted if necessary. Adjust injectors to 2176 psi (150 kg/cm² )) for turbo models and 1885 psi (132.5 kg/cm² ) for all others.
   NOTE: New and rebuilt injectors have a settling effect of approximately 72.5 psi (5.1 kg/cm² ). When installing new/rebuilt injectors in conjunction with used injectors, the new/rebuilt injectors must have a 72.5 psi (5.1 kg/cm² ) higher opening pressure.

   Fig 1: Fuel Injector Socket Wrench Extension (Turbo Diesel Models Only)