Mitsubishi Pick-ups and Montero 1983-1995 Repair Guide

Diagnosis And Testing

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For further Diagnosis and Testing refer to Emission Controls in this guide.

CRANK ANGLE SENSOR



See Figures 1, 2 and 3

The crankshaft angle sensor functions to detect the crank angle (position) of each cylinder, and converts this data into pulse signals, which are then input to the engine control module. The engine control module, based upon those signals, calculates the engine rpm, and also regulates the fuel injection timing and the ignition timing.

The power for the crankshaft angle sensor is supplied from the MFI relay and is grounded to the vehicle body. The crankshaft angle sensor, by intermitting the flow (to ground) of the 5 volt signal applied from the engine control module, produces pulse signals.

This part is easy to test, but must be removed from the vehicle to do so.

  1. First test the circuit to the sensor. Unplug the sensor connector, turn the ignition ON and check for 12 volts between one of the terminals and ground. The other terminals are return signals to the ECU, do not use them for a voltmeter ground.
  2.  
  3. Turn the ignition OFF .
  4.  
  5. Remove the distributor assembly and reconnect the plug to the crank angle sensor.
  6.  
  7. Peel back the insulation-wrap just far enough to connect a voltmeter to the wires and ground the coil high tension wire.
  8.  
  9. With the voltmeter connected to a good chassis ground, turn the ignition ON and slowly rotate the distributor. One of the return signal wires should have 5 volts off and on with each degree of rotation. The other should have 5 volts off and on with each 120 degrees of rotation.
  10.  
  11. Visually check the rotor plate for rust or damage.
  12.  



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Fig. Fig. 1: The crankshaft position sensor location on the 3.0L (12 valve) engine



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Fig. Fig. 2: The crankshaft and camshaft position sensor wiring schematic for the 3.0L (12 valve) engine



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Fig. Fig. 3: Crankshaft position sensor location and wiring schematic for the 3.0L (24 valve) and 3.5L DOHC engines

IGNITION COIL AND BALLAST RESISTOR



See Figures 4, 5 and 6

2.0L and 2.6L Engines
  1. Measure the resistance of the external resistor on the coil by connecting the probes of an ohmmeter across the two resistor connectors. Resistance should be as follows or the unit should be replaced.

    2.0L engine (1983-86): 1.35 ohms
     
    2.0L engine (1987-89): 1.2-1.4 ohms
     
    2.6L engine (1983-86): 1.04-1.27 ohms
     
    2.6L engine (1987-88): 1.25 ohms
     
    2.6L engine (1989-90): 1.12-1.38 ohms
     

  2.  

  1. Measure the resistance across the coil primary circuit by connecting an ohmmeter between the (+) and (-) coil connectors. Resistance must be approximately as follows or the coil should be replaced.

    2.0L engine (1983-86): 1.2 ohms
     
    2.0L engine (1987-89): 1.08-1.32 ohms
     
    2.6L engine (1983-86): 1.04-1.27 ohms
     
    2.6L engine (1987-88): 1.25 ohms
     
    2.6L engine (1989-90): 1.12-1.38 ohms
     

  2.  

  1. Set your ohmmeter to the x1000 scale and measure the resistance between the connector inside the coil tower and the coil (+) terminal. This is secondary resistance and must be as follows, or the unit should be replaced.

    2.0L engine (1983-86): 1.2 kilohms
     
    2.0L engine (1987-89): 1.08-1.32 kilohms
     
    2.6L engine (1983-86): 7.1-9.6 kilohms
     
    2.6L engine (1987-88): 11.0 kilohms
     
    2.6L engine (1989-90): 9.4-12.7 kilohms
     

  2.  

  1. Inspect the unit for oil leaks and cracks in the coil tower, and replace it if any defects are noted.
  2.  



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Fig. Fig. 4: Checking the resistance of the external resistor



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Fig. Fig. 5: Checking primary coil resistance



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Fig. Fig. 6: Checking secondary coil resistance

2.4L and 3.0L (12 Valve) Engines

See Figure 7

  1. Measure the resistance across the coil primary circuit by connecting an ohmmeter between the (+) and (-) coil connectors. Resistance must be approximately 0.72-0.88 ohms or the coil should be replaced.
  2.  
  3. Set your ohmmeter to the x1000 scale and measure the resistance between the connector inside the coil tower and the coil (+) terminal. This is secondary resistance and must be 10.3-13.9 kilohms, or the unit should be replaced.
  4.  
  5. Inspect the unit for cracks in the coil tower, and replace it if any defects are noted.
  6.  



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Fig. Fig. 7: Coil assembly for the 2.4L and 3.0L (12 valve) engines

3.0L (24 Valve) Engines

See Figures 8 and 9

  1. To test the primary coil resistance, measure the resistance between the terminal (1) of the connector (power source) and the terminals of each coil.
  2.  
  3. Measurement points:

    A coil: Terminals 1 and 11
     
    B coil: Terminals 1 and 13
     
    C coil: Terminals 1 and 12
     

  4.  

Standard value: 0.67-0.81 ohms

  1. To test the secondary coil resistance, switch the ohmmeter to the x1000 scale and measure the resistance between each terminal for a high pressure.
  2.  
  3. Measurement points:

    A coil
     
    B coil
     
    C coil
     

  4.  

Standard value: 11.3-15.3 kilohms

  1. Inspect the unit for cracks and replace it if any defects are noted.
  2.  



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Fig. Fig. 8: The primary coil configuration and resistance check-3.0L (24 valve) engine



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Fig. Fig. 9: Checking secondary coil resistance-3.0L (24 valve) engine

3.5L Engines

See Figures 10 and 11

  1. To test the primary coil resistance, measure the resistance between the terminals for each cylinder (No. 1 & No. 4, No. 2 & No. 5, No. 3 & No. 6) of the ignition coil.
  2.  

Standard value: 0.69-0.85 ohms

  1. To test the secondary coil resistance, switch the ohmmeter to the x1000 scale and measure the resistance between the high voltage terminals for each cylinder (No. 1 & No. 4, No. 2 & No. 5, No. 3 & No. 6) of the ignition coil as shown in the illustration.
  2.  

Standard value: 15.3-20.7 kilohms

  1. Inspect the unit for cracks and replace it if any defects are noted.
  2.  



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Fig. Fig. 10: Checking the primary ignition coil resistance-3.5L engine



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Fig. Fig. 11: Checking secondary ignition coil resistance-3.5L engine

 
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