823648 Mariner COVER, Diaphragm, DIAPHRAGM (WMC 31 A/32A)

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Top View Of Engine
Right Side View Of Engine
Front View Of Engine
Rear View Of EngineEngine Information
The Caterpillar 3412 Generator Set Engine uses a microprocessor based electronic engine control to provide electronic governing, automatic fuel ratio control and torque rise shaping. Two communication data links are provided to monitor engine characteristics are provided to monitor engine characteristics and provide diagnostic information.The engine is twin series turbocharged and jacket water aftercooled with direct fuel injection. The engine has a SAE No. "0" (zero) flywheel housing and dual viscous dampers. This engine is designed for either right or left hand service and to fit within a 1220 mm (48 in) width for oil well service-fracturing rig applications.Individual injection pumps and fuel lines, one for each cylinder, meter and pump fuel under high pressure to and injection nozzle for each cylinder.New "collared washer" fuel injection lines are made from high strength steel. They incorporate a collared washer at the end of the fuel line to reinforce fuel line connections and increase system reliability.The 3412 Generator Set Engine has a high capacity fuel system. The plunger area for the new fuel system is increased over other 3400 Family engines. A high injection-rate camshaft, with increased stroke, is also used. This combination of increased plunger area, longer stroke and high injection rate results in a significant increase in injection pressure and volumne, with a reduction in injection duration. This yields higher power output, cleaner combustion, lower smoke levels and improved fuel economy.A full range electronic governor controls the fuel injection pump output to maintain the engine rpm, called for by the throttle position sensor.The cooling system consists of a gear driven centrifugal pump, with two thermostats which regulate the coolant temperature. A customer supplied fan drive and cooling system (radiator) is required.The engine lubricating oil, which is both cooled and filtered, is supplied by a gear driven 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 should become plugged.Engine efficiency and engine performance depend on adherence to proper operation and maintenance recommendations, and the use of recommended fuels and lubrication oils.Follow the recommended Maintenance Management Schedule with emphasis on air cleaner, oil, oil filter, fuel and fuel filter maintenance found in the Operation & Maintenance Manual.Starting The Engine
The Electronic Control equipped engine may need to crank slightly longer than a mechanically governed engine, because some oil pressure is required for the electronic actuator to move the rack. The check engine light should be ON while the engine is cranking, but should GO OUT, after engine oil pressure is achieved. At temperatures below 0°C (32°F), it may be necessary to spray starting fluid into the air cleaner inlet (follow the recommended procedure in the Operation & Maintenance Manual. If the engine fails to start in 30 seconds, allow the starter motor to cool for two minutes before trying it again.Cold Mode Operation
The Electronic Control system automatically idles the engine at 900 to 1000 rpm for the correct warm up time after a cold engine start [approximately less than 5°C (40°F)]. The Electronic Control system periodically checks the engine response and will reduce the idle speed down to 600 rpm when the engine is warmed.After the engine is started and the cold mode operation is completed, the engine can be operated at low rpm and low power. The engine will reach normal operating temperature faster when operated at low rpm and low power demand than when idled at no load.Shutoff Solenoid Override
A manual shutoff solenoid override lever is located on the side of the fuel pump. The engine can be shut off by rotating the manual shutoff lever in the counterclockwise (CCW) direction. Rotating the manual shutoff lever in the clockwise (CW) direction disables the shutoff solenoid.If the solenoid has been disabled, the engine can be shut OFF by using the manual shutoff lever on the side of the fuel pump.
DO NOT operate the engine without the rack actuator solenoid (BTM) in place and with the fuel shutoff solenoid disabled. Excessive engine speed may result.
Customer Specified Parameters
The Electronic Control system is capable of being programmed for several customer specified parameters. These parameters and a brief explanation of each are in the Operation And Maintenance Guide.Glossary Of Electronic Control Terms
Actual RackThe ECM's interpretation of the signal from the Rack Position Sensor, read as "Rack Pos" on the ECAP.Aftermarket DeviceA device or accessory installed by the customer after the engine is delivered.Alternating Current (AC)The direction of current flow changes (alternates) regularly and constantly.American Wire Gauge (AWG)A measure of the diameter (and therefore the current carrying ability) of electrical wire. The smaller the AWG number, the larger the wire.Before Top Center (BTC)The 180 degrees of crankshaft rotation before the piston reaches Top Center (normal direction of rotation).Boost Pressure SensorThis sensor measures inlet manifold air pressure and sends a signal to the ECM.Brushless Torque Motor (BTM)Solenoid used to move fuel rack servo spool valve, also called rack solenoid. Bypass CircuitA circuit, usually temporary, to substitute for an existing circuit, typically for test purposes.CalibrationAs used here, is an electronic adjustment of a sensor signal.Coolant Temperature SensorUsed to set Cold Mode and to trigger the shift out of Cold Mode during engine warmup.CodeSee Diagnostic Code.Data LinkAn electrical connection for communication with other microprocessor based devices that are compatible with the American Trucking Association and SAE Standards. The Data Link is also the communication medium used for programming and troubleshooting with Caterpillar service tools.Desired Rack Position ("Des Rack Pos" on ECAP)The rack setting calculated by the ECM as needed to attain or maintain the Desired RPM.Desired RPMAn input to the electronic governor within the ECM, and the output signal from the engine control logic within the ECM. The engine control logic uses inputs from the Throttle Position Sensor, Engine Speed Sensor, Cold Mode, and Customer Parameters to determine "Desired RPM".Desired Timing Advance ("Des Timing Adv" on ECAP)The injection timing advance calculated by the