407920-2350 ZEXEL CONTROL UNIT Cross 4079202350

Abnormal engine running, smoke emission, and engine knock can be symptoms of nozzle malfunction. Each nozzle must be isolated one at a time in order to determine the malfunctioning nozzle.1. Start the engine.
A nozzle will be damaged if the top of the nozzle turns in the body. The engine will be damaged if a defective nozzle is used because the fuel spray pattern that comes out of the nozzle will be incorrect. Nozzles can be permanently damaged by twisting if only one wrench is used to loosen or tighten the fuel line nuts. Do NOT let the tops of the nozzles turn when the fuel lines are loosened. Use one wrench to hold the nozzle and another to loosen the fuel line nut.
2. Loosen each fuel line nut at the fuel injection pump, one at a time. A cloth or similar material must be used to prevent fuel from spraying on the hot exhaust components. Tighten each nut before loosening the next nut.3. A defective nozzle may be identified when a fuel line nut is loosened and: * the exhaust smoking is partially or completely eliminated* engine performance is not affectedA nozzle suspected of being defective should be removed. A new nozzle should be installed in the cylinder to determine if the removed nozzle is defective.Removing and Installing Fuel Injection Nozzles
Special tooling is required to remove and install nozzles. Refer to the Service Manual for information. Consult with your Caterpillar dealer for assistance.Inspect, Rebuild, or Exchange
If the engine is operated until the components fail, additional engine damage can result. Caterpillar recommends that the following components be inspected in order to ensure reliable engine performance:* Jacket Water Pump* Raw/Sea Water Pump* Alternator* Starting Motor* Air Compressor Caterpillar RecommendationTo minimize downtime, Caterpillar recommends the use of Remanufactured components (subject to availability) as the most cost effective option. Removal and InstallationRefer to the Service Manual or contact your Caterpillar dealer for assistance with removal and installation of engine components.Water Pumps
A failed water pump might cause severe engine overheating problems that could result in cracks in the cylinder head, a piston seizure or other potential damage to the engine.Visually inspect the water pump for leaks. If leaking is observed, replace all seals. Refer to the service manual for the disassembly and assembly procedure.Inspect the component for wear, cracks, pin holes and proper operation. Refer to the service manual or consult with your Caterpillar dealer if repair or replacement is needed.Raw/Sea Water Pump
If the pump flow is reduced or if the pump can not self-prime, check for excessive wear of the impellers and the port plates. Refer to the Service Manual for the disassembly and assembly procedure. Rebuild or exchange the pump if necessary.Alternator
Caterpillar recommends a scheduled inspection of the alternator. Inspect the alternator for loose connections and proper battery charging. Inspect the ammeter gauge during engine operation to ensure the batteries and/or electrical system is performing correctly. Make repairs as necessary. Refer to the Service Manual.Check the alternator and battery charger for