Injection Nozzles

If exhaust gives off intermittent clouds of black smoke, this usually means one or more nozzles are operating unevenly. If exhaust offers a rumbling noise, it usually indicates one cylinder is partly or completely out of action. To determine problem, check injection nozzles as follows:

1. At idle, loosen each injection pipe cap nut (in turn) 1/2 turn. If sound of engine does not change, part of problem is a defective nozzle or inadequate sealing between pipe union and nozzle holder.
2. Raise engine RPM above idle speed and repeat test procedure. If engine still does not run erratically with nut loosened, repair or replace that particular nozzle. If engine runs erratically when nut is loosened, nozzle is operating properly. Tighten 1/2 turn and check next nozzle.
   NOTE: On 240D and 300D, nozzle opening pressure should be 1635-1750 psi (115-123 kg/cm² ) for new nozzles. A minimum of 1422 psi (100 kg/cm² ) for used nozzles. On 300SD, nozzle opening pressure should be 1958-2074 psi (135-143 kg/cm² ). Difference in opening pressures in one engine should not exceed 71 psi (5 kg/cm² ).