106873-2981 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1068732981 me161176

The engine is turbocharged and air-to-air aftercooled (ATAAC) with direct fuel injection.The 3176 is an electronically controlled, mechanically actuated unit injector diesel engine. Timing advance is achieved by precise control of injector firing. Engine speed is controlled by adjusting the firing duration. A pulse wheel provides information to the fuel cooled ECM (Electronic Control Module) for detection of cylinder position and engine speed.The 3176 electronic engine control system was designed to provide electronic governing, automatic air fuel ratio control, torque rise shaping, injection timing control and system diagnostics. Additional benefits such as cruise control, vehicle speed limiting, low and high gears engine speed limiting (progressive shift engine speed control), PTO governor, data link and multi-torque ratings provide for additional engine fuel economy, driver comfort and serviceability.The fuel system is a mechanically actuated, electronically controlled unit injector combining the pumping, electronic fuel metering and injecting elements in a single unit to produce higher injection pressures (22,000 psi [151 600 kPa]). High injection pressures help to reduce fuel consumption and particulate emissions.The use of this type of unit injector provides total electronic control of injection timing. The injection timing is varied as a function of engine operating conditions. This optimizes the engine's performance for starting, emissions, noise, fuel consumption and driveability.A full range electronic governor is utilized and controls the fuel injection output to maintain the engine speed desired by the 3176 system. The governor functions like the Caterpillar mechanical governor in the mid-range, but includes additional features. These include programmable isochronous low idle and 20 rpm governor overrun.The 3176 has built-in diagnostics to assure that all components are functioning and operating properly. In the event of a system component deviation from programmed limits, the operator will be alerted to the condition by a dashboard mounted "Check Engine" light.A Caterpillar service tool may be used to read the numerical code of the faulty component. Intermittent faults are logged and stored in the system memory. Refer to Engine Diagnostics section of this publication for alternative methods.The cooling system consists of a gear driven pump, with one thermostat which regulates the engine coolant temperature, a plate type oil cooler and a radiator incorporating a shunt system.The 3176 does not have a cylinder block water cooling system. Instead, the cast water manifold in the spacer deck distributes 65% of the coolant volume to each of the cylinder liners and the remaining 35% flows directly to the cylinder head.The engine lubricating oil, which is both cooled and filtered, is supplied by a gear-type pump. Bypass valves provide unrestricted flow of lubrication oil to the engine parts when oil viscosity is high, or if either the oil cooler or the oil filter elements (paper cartridge) should become plugged.Multi-Torque Rating (if equipped)
This feature provides higher torque levels and better fuel economy while in top gear only. The 3176 electronics are able to determine when the vehicle is in top gear by calculating the engine rpm/vehicle speed ratio. A ratio of less than 26.6 will provide higher