Preliminary Testing

Injection nozzle problems are usually accompanied by knocking in one or more cylinders, engine overheating, loss of power, smoky black exhaust, engine misfire, excessive blue smoke during cold start and increased fuel consumption. To locate and correct faulty injectors, use following procedure.

With engine running at fast idle, loosen line unions on each injection nozzle one at time. If engine speed remains constant with line loosened, that nozzle is defective.
To remove nozzle, detach injector lines as group. Use special extra-deep socket (US 2775) to remove injection nozzles. To remove or install injector nozzles on Turbo models, remachine 1/2" (13 mm) socket wrench extension to dimensions shown. See Fig 1 .
To disassemble, place upper part of nozzle in vise and loosen lower part. Then reverse position of nozzle in vise, lightly clamp lower part of nozzle, and carefully remove internal parts from lower part of nozzle. Do not interchange parts from one nozzle to another.
Use fresh diesel fuel to clean injector parts. Check for carbonized or rough needle seat, worn injection needle and/or nozzle, or needle binding in nozzle. Reassemble injector and tighten halves to 51 ft. lbs. (69 N.m).
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 settling effect of approximately 72.5 psi (5.1 kg/cm² ). When installing new/rebuilt injectors in conjunction with used injectors, new/rebuilt injectors must have 72.5 psi (5.1 kg/cm² ) higher opening pressure than that of used injectors.

Fig 1: Fuel Injector Socket Wrench Extension Illustration applies to Turbo models only.