3F3-00004-0 Tohatsu PISTON (0.5MM O/S)

Illustration 1 g01442416
Right side view
(1) Engine oil temperature sensor
(2) Pressure switch for the coolant pump (inlet)
(3) Pressure sensor for unfiltered oil
(4) Pressure sensor for filtered oil Engine oil temperature sensor (1) - An oil temperature sensor measures the engine oil temperature. A high oil temperature will activate an alarm or a shutdown. The trip points can be programmed with the Caterpillar Electronic Technician (Cat ET). To observe the output value of the sensor, use Cat ET to view the "Engine Oil Temperature" parameter.Pressure switch for the coolant pump (inlet) (2) - A pressure switch is located at the inlet for the engine jacket water. If the inlet pressure is too high, the switch will activate a shutdown. To observe the status of the switch, use the Caterpillar Electronic Technician (Cat ET) to view the "Engine Coolant Pump Pressure" parameter.Oil pressure sensors (3) and (4) - The engine oil pressure is measured before the oil filters (3) and after the oil filters (4). An alarm or a shutdown can be activated by any of the following occurrences: low filtered oil pressure, low oil filter differential pressure and high oil filter differential pressure. The trip point for the activation of a warning or a shutdown for oil filter differential pressure can be programmed with Cat ET. To observe the value of the output of the sensor, use Cat ET to view the "Engine Oil Pressure" or the "Unfiltered Engine Oil Pressure" parameter.
Illustration 2 g01442420
Typical front and left side
(5) Compressor discharge pressure sensor (if equipped with ASM)
(6) Air inlet pressure sensor (optional location)
(7) Detonation sensor Compressor discharge pressure sensor (5) - This sensor only applies to engines that are equipped with an Auxiliary Sensing Module (ASM). The sensor is located at the top of the duct between the compressor outlet and the inlet to the throttle. The ASM uses the signal from this sensor to rapidly respond to changes in engine load.Air inlet pressure sensor (6) - This sensor is connected to the inlet manifold. If the engine is equipped with an ASM, the sensor is located at the rear of the manifold. Otherwise, this sensor is located at the front of the manifold. The sensor monitors the absolute manifold pressure. This is the atmospheric pressure plus the gauge pressure. The information is used by the ECM to calculate the air flow. To observe the output value of the sensor, use Cat ET to view the "Inlet Manifold Air Pressure (abs)".Detonation sensors (7) - The detonation sensors monitor the engine for mechanical vibrations. Each sensor monitors two cylinders. The sensor produces a voltage signal that is proportional to the engine detonation. This information is processed by the ECM in order to determine detonation levels. To eliminate detonation, the ECM retards the timing of the cylinder. If detonation continues, the ECM will shut down the engine. To observe the value of the output of the sensors, use Cat ET to view the "Cylinder #X Detonation Level". The "X" is the number for the particular cylinder.
Illustration 3 g01442421
(6) Air manifold inlet pressure sensor (with ASM)
(8) Engine coolant pressure sensor (outlet)
(9) Engine coolant temperature sensor
(10) Inlet manifold air temperature sensor
(11) Speed/timing sensor Engine coolant pressure sensor (outlet) (8) - A pressure switch is located at the outlet for the engine jacket water. If the outlet pressure is too low, the ECM will activate a shutdown.Engine coolant temperature sensor (9) - The temperature sensor is located in the water temperature regulator housing. To monitor the coolant temperature, the element must be in contact with the coolant. Otherwise, the sensor will not function properly. A high coolant temperature will activate an alarm or a shutdown. A low coolant temperature will only activate an alarm. The trip points for the activation can be programmed with Cat ET. The engine can be restarted after a shutdown due to high engine coolant temperature. However, another shutdown will occur after one minute if the temperature remains high. To observe the value of the output of the sensor, use Cat ET to view the "Engine Coolant Temperature" parameter.Inlet manifold air temperature sensor (10) - A sensor for monitoring the inlet air temperature is located in the inlet elbow for the number twenty cylinder. Excessive inlet air temperature can activate an alarm or a shutdown during high load or low load operation. The trip points for activation can be programmed with Cat ET. To observe the value of the output of the sensor, use Cat ET to view the "Inlet Air Temperature" parameter.Engine speed/timing sensor (11) - The engine speed/timing sensor is located at the rear end of the left camshaft. The ECM monitors the engine speed/timing sensor in order to determine the position of the crankshaft and the engine rpm. With the position of the crankshaft, the ECM is able to determine the ignition timing. To observe the engine speed in rpm, use Cat ET to view the "Engine Speed" parameter.
Illustration 4 g01442422
Engine speed sensors
(12) Engine speed sensor for the ASM
(13) Engine speed sensor for the Generator Set Control (GSC+) Engine speed sensor for the ASM (12) - This sensor only applies to engines that are equipped with an ASM. The ASM uses the signal from this sensor to accurately determine engine speed. In addition, the ASM determines the rate of change of the engine speed. The ASM uses this information to rapidly respond to changes in engine load. The ASM sends information on engine speed to the master ECM via the Cat Data Link.Engine speed sensor for the GSC+ (13) - The GSC+ uses the signal from this sensor to monitor the engine rpm.