Crankshaft position sensor (345), Simtec
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Crankshaft position sensor (345), Simtec
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Crankshaft position sensor (345)
The control module receives information on crankshaft position and speed from the crankshaft position sensor.
Rpm is used to:
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indicate engine operating point (together with the engine load). The operating point indicates which values are to be used in matrices and tables.
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Crankshaft angle is used to calculate when angle-related functions are to be activated. These include ignition, injection and knock detection.
A perforated disc with 58 ribs is mounted on the crankshaft. The sensor is inductive and is mounted in the engine's crankcase wall. The distance between the sensor and the perforated disc cannot be adjusted.
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Pin No.
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Signal type
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Description
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1
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Signal
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Connected to ECM pin 37(A).
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2
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Signal
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Connected to ECM pin 5(A).
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The sensor works as a generator and provides a sine form alternating current. By measuring the frequency the control module can determine the engine speed. After the perforated disc's 58th rib there are two ribs missing. When rib 1 then passes the sensor the control module knows that the crankshaft is 114 before top dead centre (TDC). If the crankshaft position sensor does not work then the signal from the camshaft sensor is used as a substitute value, although with inferior engine performance.
Voltage from the crankshaft sensor varies with engine speed. It is the frequency, not voltage, that is important to the control module. As soon as the control module receives pulses from the crankshaft sensor, it grounds the fuel pump relay.
