See Figure 1
The Crankshaft Position Sensor (CKPS) detects slots cut into the transaxle drive plate extension. There are 3 sets of slots, each set containing 4 slots, for a total of 12 slots. Basic timing is determined by the position of the last slot in each group. Once the PCM senses the last slot, it determines crankshaft position (which piston will next be at Top Dead Center/TDC) from the camshaft position sensor input. The 4 pulses generated by the CPS represent the 69°, 49°, 29°, and 9° Before Top Dead Center (BTDC) marks. It may take the PCM one engine revolution to determine crankshaft position during cranking.
The PCM uses the camshaft position sensor to determine fuel injector sequence. The PCM determines ignition timing from the CKPS. Once the crankshaft position has been determined, the PCM begins energizing the injectors in sequence.
The CKPS is located in the transaxle housing, above the vehicle speed sensor. The bottom of the sensor is positioned next to the drive plate.
The distance between the bottom of the sensor and the drive plate is critical to the operation of the system.
See Figures 2, 3 and 4
Before testing any electrical component, inspect the wiring and connectors for damage. Also wiggle the connectors to ensure a that they are firmly engaged. For this procedure a dwell meter, or the equivalent, will be needed.
- Unplug the Crankshaft Position Sensor (CKPS) connector.
- Turn the ignition ON .
Using a voltmeter, measure the voltage from the wiring harness connector 8-volt supply circuit (orange wire) to ground. Refer to the accompanying wiring illustration.
- If the voltage is 8-9.5 volts, skip to the next step.
- If the voltage measured is lower than 8 volts, or higher than 9.5 volts, the CKPS is not receiving the correct current to function properly. There is a problem in the wiring or related components.
- Turn the ignition OFF .
- Attach the CKPS wiring and engine wiring harness connectors back together.
- Attach a dwell meter to the battery. Attach the lead probe of the dwell meter to the sensor signal wire (light blue with dark blue tracer) by backprobing the connector or by using jumper cables between the terminals. Refer to the accompanying wiring illustration.
- Place the dwell meter out of the way of any moving components of the engine, and in a position in which it can be seen once the engine is started.
- Turn the engine ON .
- Watch the dwell meter for one or two minutes while the engine is idling. The dwell shown should be a steady 49-51%. If there is any fluctuation, or the dwell time is not 49-51% the CKPS is defective and must be replaced with a new one.
REMOVAL & INSTALLATION
See Figure 5
The sensor is located on the passengers side of the transmission housing, above the differential housing. The bottom of the sensor is positioned above the drive plate.
- Disconnect the negative battery cable.
- Unplug the CKPS electrical connector from the wiring harness.
- Unscrew the CKPS retaining bolt.
- Pull the sensor straight out of the transaxle housing.
- If installing the original sensor, clean off the old spacer from the sensor face. A new spacer must be attached to the sensor face before installation. If the sensor is being replaced with a new one, confirm that the paper spacer is attached to the face of the new sensor.
- Slide the sensor into the hole in the transaxle and push the sensor in until contact is made with the drive plate. While holding the sensor in this position, install and tighten the retaining bolt to 9 ft. lbs. (12 Nm).
- Plug the CKPS wiring connector into the wiring harness.
- Connect the negative battery cable.