C7 On-highway Engine Caterpillar

Illustration 1	g01607093
Left side view (1) High pressure fuel pump (2) Fuel rail (3) Pressure relief valve for fuel rail (4) Coil for the ARD purge air actuator (5) Engine Control Module (ECM) (6) Air inlet heater relay (7) Main fuel control valve (8) Pilot fuel control valve (9) Air compressor (10) Fuel enable valve (11) Secondary fuel filter (12) Cleaning port for the Aftertreatment Regeneration Device (ARD) (13) Optional hand priming pump (14) Fuel transfer pump

Illustration 2	g01523649
Right side view (15) Venturi for the combustion air supply (16) Air pressure control valve (17) CGI control group (18) Venturi for the CGI system (19) Oil filter (20) Ignition coil (21) CGI precooler (22) Spark plug (23) ARD combustion head (24) ARD Body (25) Flywheel housing (26) Aftertreatment Regeneration Device (ARD) (27) Variable Nozzle Turbocharger (VNT)

Illustration 3	g01523650
Right side view of the Diesel Particulate Filter (DPF) (28) Inlet to the DPF (29) Outlet for CGI (30) Outlet from the DPF

The engine is a in-line six cylinder engine. The firing order of the engine is 1-5-3-6-2-4. The engine's rotation is counterclockwise when the engine is viewed from the flywheel end of the engine. The engine utilizes a turbocharger and an air-to-air aftercooler. The engine has a bore of 110.0 mm (4.33 inch) and a stroke of 127.0 mm (5.00 inch). The displacement is 7.2 L (439 cu in).

The fuel system eliminates many of the mechanical components that are used in a pump-and-line system. The fuel system also provides increased control of the timing and increased control of the fuel air mixture. The timing advance is achieved by precise control of the fuel injector timing. Engine rpm is controlled by adjusting the injection duration. A special pulse wheel provides information to the ECM for detection of cylinder position and engine rpm.

The engine has built-in diagnostics in order to ensure that all of the components are operating properly. In the event of a system component failure, the operator will be alerted to the condition via the check engine light that is located on the dashboard. An electronic service tool can be used to read the numerical code of the faulty component or condition. Also, the cruise control switches can be used to flash the code on the check engine light. Intermittent faults are logged and stored in memory.

Starting The Engine

The engine's ECM will automatically provide the correct amount of fuel in order to start the engine. Do not hold the throttle down while the engine is cranking. If the engine fails to start in twenty seconds, release the starting switch. Allow the starting motor to cool for two minutes before the starting motor is used again.

Cold Mode Operation

Starting the engine and operation in cold weather is dependent on the type of fuel that is used, the oil viscosity, and other optional starting aids. For more information, refer to the Operation and Maintenance Manual, "Cold Weather Operation".