PLUG 1195364 - Caterpillar

Either too much fuel or not enough fuel for combustion can be the cause of a problem in the fuel system. Often, work is done on the fuel system when the problem is really with another part of the engine. Excessive smoke from the exhaust is a difficult problem. Excessive smoke that comes from the exhaust can be caused by a worn unit injector. Excessive smoke can also be caused by one or more of the reasons that follow:
There is not enough air for good combustion.
There is an overload during a high altitude condition.
There is oil leakage into the combustion chamber.
There is not enough compression.
The fuel injection timing is incorrect.Procedure for Fuel Priming
Illustration 1 g00294863
Fuel system components (left side view) (1) Fuel return line from the cylinder head (2) Fuel priming pump (3) Fuel filter base (4) ECM (5) Fuel supply line to the cylinder head (6) Fuel transfer pump (7) Fuel filter (8) Air purge cap
Illustration 2 g00294865
Fuel system components (front view) (9) Air purge plug (10) Fuel return (11) Fuel inletNote: If the fuel system runs dry of fuel or air is introduced into the system, the following procedure must be followed.
Loosen the air purge cap (8) .
Unlock and operate the fuel priming pump (2) until fuel appears at the air purge cap (8) . Tighten the air purge cap (8) .
Loosen the air purge plug (9) for two turns. Continue operating the fuel priming pump (2) until fuel appears at the air purge plug (9) . Tighten the air purge plug (9) .
Continue operating fuel priming pump (2) until a resistance is felt. Push in and lock the hand priming pump.
Once the system is pressurized, crank the engine as soon as possible. The engine should start within 15 seconds. If the engine does not start after 30 seconds, stop cranking the engine. A period of 2 minutes is needed for the starter to cool before proceeding.
If the engine does not start, repeat the procedure.Fuel System Inspection
A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.
Check the fuel level in the fuel tank. Check the vent in the cap for the fuel tank for dirt.
Check the fuel lines for fuel leakage. Check the fuel lines for a worn bend or a restriction. Check that the fuel return line has not collapsed within the sections that are exposed to heat.
Install a new fuel filter.
Remove any air that may be in the fuel system. Refer to the topic "Procedure for Fuel Priming" in this service manual.Fuel System Pressure
The typical fuel pressure of the engine at operating temperature can vary. At low idle, the fuel pressure can be 538 kPa (78 psi). At high rpm, the fuel pressure can be 641 kPa (93 psi).The performance of the unit injector deteriorates when the fuel pressure drops below 241 kPa (35 psi). Low-power complaints and erratic operation can occur in this situation. Check for a plugged fuel filter or air in the