1998 ford ranger engine started running rough, went to auto parts store had battery checked (OK) would not start back, changed starter in parking lot , starter clicks but engine will not turn over

OPERATION

See Figure 1

The Crankshaft Position (CKP) sensor, located on the front cover (near the crankshaft pulley) is used to determine crankshaft position and crankshaft rpm. The CKP sensor is a reluctance sensor which senses the passing of teeth on a sensor ring because the teeth disrupt the magnetic field of the sensor. This disruption creates a voltage fluctuation, which is monitored by the PCM.

Fig. Fig. 1: The CKP sensor (A) is triggered by the teeth which are machined into the crankshaft damper (B)

TESTING

See Figures 2 and 3

Using a DVOM set to the DC scale to monitor less than 5 volts, measure the voltage between the sensor Cylinder Identification (CID) terminal and ground by backprobing the sensor connector. If the connector cannot be backprobed, fabricate or purchase a test harness. The sensor is okay if the voltage reading varies more than 0.1 volt with the engine running at varying RPM.

Fig. Fig. 2: CKP sensor wire harness connections for all engines except the 4.0L (VIN X and E) engines

Fig. Fig. 3: CKP sensor wire harness connections for the 4.0L (VIN X and E) engines

REMOVAL & INSTALLATION

See Figures 4 through 8

Fig. Fig. 4: To remove the CKP sensor, first disconnect the wire harness plug ...

Fig. Fig. 5: ... then unbolt the sensor and pull it away from the engine-crankshaft damper removed for clarity

To install:

When installing a new sensor on the 4.0L (VIN X and E), position the sensor against the crankshaft damper. There are small rub tabs which wear off and allow the sensor to be perfectly spaced from the damper.

Fig. Fig. 6: Exploded view of the 2.3L and 2.5L Crankshaft Position (CKP) sensor

Fig. Fig. 7: Exploded view of the 3.0L Crankshaft Position (CKP) sensor-5.0L engine is similar

Fig. Fig. 8: Exploded view of the 4.0L (VIN X) Crankshaft Position (CKP) sensor-4.0L SOHC (VIN E) engine is similar