Chrysler Front Wheel Drive Cars 4-CYL 1981-1995 Repair Information

Crankshaft Position Sensor (CKPS)

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OPERATION



Eagle Throttle Body Fuel Injection (TBI) System

See Figures 1 and 2

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Fig. Fig. 1: The CKPS (known as the engine speed sensor on Premier models) is mounted in the transaxle housing



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Fig. Fig. 2: The CKPS (engine speed sensor) is a Hall-effect device which senses a change in its magnetic field as the grooves, cut into the edge of the flywheel, pass underneath

The Eagle TBI system is used only on 2.5L Premier engines.

This sensor is attached to the flywheel/drive plate housing. The sensor detects the flywheel/drive plate teeth as they pass during engine operation and provides engine speed and crankshaft angle (position) information to the PCM.

The flywheel/drive plate has a larger trigger tooth and a notch located 90 degrees before each Top Dead Center (TDC) position. There are 12 small teeth between the notch and TDC.

When a small tooth and notch pass under the magnet core in the sensor, the concentration and then collapse of the magnetic flux induces a small voltage (spike) into the sensor pick-up coil winding. These small voltage spikes enable the PCM to count the teeth at they pass the sensor.

When a larger tooth and notch pass under the magnet core in the sensor, the increased concentration and then collapse of the magnetic flux induces a higher voltage (spike) into the sensor pick-up coil winding.

The high voltage (spike) indicates to the PCM that a piston will be at TDC position 12 teeth later. The ignition timing for the cylinder is either advanced or retarded as necessary by the PCM according to the sensor inputs.

Chrysler Multi-Point Fuel Injection (MFI) System

The MFI system is used on 2.2L and 2.5L turbocharged and flex fuel engines.

2.2L TURBO III ENGINE

See Figures 3, 4 and 5



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Fig. Fig. 3: The crankshaft position sensor used on 2.2L Turbo III engines is a Hall-effect device



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Fig. Fig. 4: The CKPS, since it is a Hall-effect device, can sense the slots cut into the outer edge of the torque converter driveplate or flywheel



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Fig. Fig. 5: The CKPS is mounted in the transaxle housing beneath the throttle body assembly

Only the 2.2L Turbo III engine utilizes separate crankshaft and camshaft position sensors; the other engines use distributor reference signals to perform the same functions.

The Crankshaft Position Sensor (CKPS) perceives slots cut into the transaxle drive plate extension. There are 2 sets of slots, each set containing 4 slots, for a total of 8 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 (CPS) input. It may take the PCM one engine revolution to determine crankshaft position during cranking.

The PCM uses the CKPS to determine fuel injector sequence and ignition timing. Once the crankshaft position has been determined, the PCM begins energizing the injectors in sequence.

The CKPS is located in the transaxle housing, below the throttle body. 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.

2.5L FLEXIBLE FUEL AND TURBO I ENGINES

The 2.5L Flex Fuel and Turbo I engines utilize distributor reference signals, like the EFI system. For the proper service procedures for the distributor pick-up sensors, refer to those procedures later in this section.

TESTING



Eagle Throttle Body Fuel Injection (TBI) System
  1. Disconnect the wire harness connector from the crankshaft position sensor.
  2.  
  3. Place a suitable ohmmeter across the terminals marked A and B on the connector.
  4.  
  5. The meter reading should be 125-275 ohms on a hot engine.
  6.  

If the sensor fails to meet the specifications during this test, replace it.

Chrysler Multi-Point Fuel Injection (MFI) System
2.2L TURBO III ENGINE

See Figures 6 and 7

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Fig. Fig. 6: Crankshaft position sensor circuit wiring schematic for 2.2L Turbo III engines



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Fig. Fig. 7: The CKPS connector terminal identification

  1. With ignition ON and engine OFF , measure voltage between terminals 1 and 2 of the camshaft position sensor harness connector. If the voltage reading is approximately 8V, the power circuit to the sensor is OK.
  2.  
  3. While varying the engine rpm, measure the voltage between terminals 3 and 2 of the CMP sensor with a DVOM on AC scale (to monitor less than 5.0V). If the reading varies more than 0.1V AC, the sensor is OK.
  4.  

REMOVAL & INSTALLATION

Eagle Throttle Body Fuel Injection (TBI) System

The CKPS is located on the torque converter housing behind the rear face of the engine on the left side.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the CKPS mounting screws.
  4.  
  5. Disengage the CKPS electrical connector.
  6.  
  7. Remove the CKPS from the transaxle.
  8.  

To install:
  1. Install the CKPS into the transaxle housing.
  2.  
  3. Install and tighten the mounting screws to 71 inch lbs. (8 Nm).
  4.  
  5. Attach the electrical connector to the CKPS.
  6.  
  7. Connect the negative battery cable.
  8.  

Chrysler Multi-Point Fuel Injection (MFI) System
2.2L TURBO III ENGINE
  1. Disconnect the negative battery cable.
  2.  
  3. The sensor is located on the side of the transaxle (front of vehicle).
  4.  
  5. Unplug the CKPS electrical connector from the wiring harness.
  6.  
  7. Unscrew the CKPS retaining bolt.
  8.  
  9. Pull the sensor straight out of the transaxle housing.
  10.  

To install:
  1. 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.
  2.  
  3. 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 108 inch lbs. (12 Nm).
  4.  
  5. Plug the CKPS wiring connector into the wiring harness.
  6.  
  7. Connect the negative battery cable.
  8.  

 
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