3512B Marine Auxiliary Engine Caterpillar

Engine Speed/Timing Sensor - Remove and Install

Usage:

3512 4DR

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Table 1
Tools Needed		Quantity
9S-9082	Engine Turning Tool	1

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Illustration 1	g00715776
Left rear view of engine (1) Flywheel housing (2) Connector (3) Primary engine speed/timing sensor (4) Secondary engine speed/timing sensor

Disconnect engine speed/timing connector (2) for the engine speed/timing sensor. Inspect the connector for corrosion, bent pins, missing pins, sockets, mismating wires, or broken wires.

Examine the plastic end of the sensor for signs of wear or contaminants such as metal filings. The plastic end of the engine speed/timing sensor should have no contaminants. The plastic end of the engine speed/timing sensor should also show no wear that is greater than 0.051 mm (0.0020 inch) from the face.

Use a screwdriver to carefully pry the plastic sensor end to the fully EXTENDED position. The fully EXTENDED position is approximately 4.75 mm (0.187 inch) beyond the metal housing of the sensor.

Grasp the plastic end of the sensor. Wiggle the sensor from one side to the other side in order to check for play. There should be no looseness.

Gently push in on the plastic end of the sensor. The plastic end of the sensor should be firm. The plastic end of the sensor should resist any retractable movement. If there is no resistance, replace the sensor.

In order to install the engine speed/timing sensor, inspect the sensor according to the inspection that is described in Step 3 through Step 6.

If the sensor end is not fully extended, use a screwdriver to carefully pry the plastic end of the sensor to the fully EXTENDED position. The fully EXTENDED position is approximately 4.75 mm (0.187 inch) beyond the metal housing of the sensor.
Note: Damage to the sensor can result if the sensor slip head is installed in a slot on the timing ring. Make sure that a tooth of the timing ring is visible in the mounting hole of the sensor prior to installation.

Examine the O-ring seal at the base of the sensor threads. If the seal is missing or damaged, install a new O-ring seal.

Install the engine speed/timing sensor into the flywheel housing. Tighten the sensor to a torque of 40 ± 5 N·m (29 ± 4 lb ft). The tip must rest against the timing reference ring.

Connect connector (2) for the engine speed/timing sensor.
Note: Be sure that the lock ring is properly snapped.
Note: The electronic injection timing must be recalibrated after the reinstallation of the engine speed/timing sensor. Refer to Troubleshooting, "Engine Speed/Timing Sensor - Calibrate".