Isuzu Cars and Trucks 1981-1991

Ignition Coil

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TESTING

Use an ohmmeter to test the ignition coil primary and secondary circuits.

G180Z, G200Z and 4ZC1-T Engines
INPUT VOLTAGE TEST
  1. Place the ignition switch in the ON position.
  2.  
  3. Using a suitable voltmeter, measure the voltage between the positive (+) terminal of the coil and a ground.
  4.  
  5. The standard voltage should be approximately 12 volts. If the voltage is not within specification, check the wiring and connectors. Replace the coil if found defective if the wiring and connectors are found OK.
  6.  



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Fig. Testing ignition coil early model conventional externally mounted coils

PRIMARY COIL RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the ignition coil negative (-) terminal.
  6.  
  7. The standard resistance should be 1.130 and 191.529 ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  

SECONDARY COIL RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the high voltage terminal.
  6.  
  7. The standard resistance should be 10.20 and 1913.80 kilo- ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  

INSULATION RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the body of the coil.
  6.  
  7. The standard resistance should be more than 10 m ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  

1986 and 1989 I-Mark Non-Turbo (4XC1-U)
INPUT VOLTAGE TEST
  1. Place the ignition switch in the ON position.
  2.  
  3. Using a suitable voltmeter, measure the voltage between the positive (+) terminal of the coil and a ground.
  4.  
  5. The standard voltage should be approximately 12 volts. If the voltage is not within specification, check the wiring and connectors. Replace the coil if found defective.
  6.  



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Fig. Ignition coil input voltage test I-Mark (non-turbo)

PRIMARY COIL RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the ignition coil negative (-) terminal.
  6.  
  7. The standard resistance should be 1.2 and 191.5 ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  



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Fig. Primary coil resistance test I-Mark (non-turbo)

SECONDARY COIL RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the high voltage terminal.
  6.  
  7. The standard resistance should be 10.2 and 1913.8 kilo- ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  



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Fig. Secondary coil resistance test I-Mark (non-turbo)

INSULATION RESISTANCE TEST
  1. Place the ignition switch in the OFF position.
  2.  
  3. Disconnect the ignition coil terminals.
  4.  
  5. Using a suitable ohmmeter, measure the resistance between the ignition coil positive (+) terminal and the body of the coil.
  6.  
  7. The standard resistance should be more than 10 m ohms. If the resistance is not within specification, check the wiring and connectors. Replace the coil if found defective.
  8.  



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Fig. Insulator resistance test I-Mark (non-turbo)



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Fig. Checking ignition coil resistance I-Mark (non-turbo). When the ohmmeter is connected as shown, infinite resistance should be read

I-Mark Turbo
CHECKING FOR OPENS AND GROUNDS
  1. Using the high scale on the ohmmeter, check the ignition coil resistance by positioning the ohmmeter probes as shown. It should read infinite resistance.
  2.  
  3. Switch the ohmmeter to the low scale and check the resistance across the coil terminals. It should read very low or zero resistance.
  4.  
  5. Now, switch to the high scale and perform a second resistance test by placing the ohmmeter probes as shown. Infinite resistance should be read.
  6.  
  7. If the resistance readings are not as described, replace the ignition coil.
  8.  



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Fig. Checking ignition coil resistance I-Mark (turbo). When the ohmmeter is connected as shown, infinite resistance should be read



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Fig. Checking ignition coil resistance I-Mark (turbo). When the ohmmeter is connected as shown, very low or zero resistance should be read

4XE1 DOHC Turbo Impulse

Refer to the Electronic Ignition Diagnosis section in this Section for "Direct Ignition System" diagnosis procedures.

Amigo, P'UP, Trooper, Trooper II with 4ZD1 and 4ZE1 Engines
RESISTANCE TESTS
  1. Disconnect the wiring along with the ignition coil and high tension cable at the connector.
  2.  
  3. Using a suitable ohmmeter, measure the resistance of the coil across the appropriate coil terminals. The resistance should be as follows:
  4.  

Primary coil resistance



4ZD1 engines (CE): 1.2 and 191.4 ohms
 
4ZE1 engines (CE): 0.81 and 190.99 ohms
 

Secondary coil resistance



4ZD1 engines (CD): 8.6 and 1913.0 kilo- ohms
 
4ZE1 engines (CD): 7.5 and 1913.5 kilo- ohms
 

Insulation resistance



4ZD1 and 4ZE1 engines (C-Body): more than 10 m- ohms
 



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Fig. Testing the ignition coil Trooper, Amigo and P-up with 4ZD1 and 4ZE1 engines

Trooper, Trooper II and Rodeo with V6 Engine
  1. Disconnect the distributor wire and wiring from the coil.
  2.  
  3. Make sure the metal ground surface is clean.
  4.  
  5. Connect an ohmmeter as shown in position 1 . Set the ohmmeter to the high ohms scale and measure the resistance. It should read infinite resistance.
  6.  
  7. Connect an ohmmeter as shown in position 2 . Set the ohmmeter to the low ohms scale and measure the resistance. It should read very low or zero resistance.
  8.  
  9. Connect an ohmmeter as shown in position 3 . Set the ohmmeter to the high ohms scale and measure the resistance. It should not read infinite resistance.
  10.  
  11. If the resistance is not as described, replace the ignition coil.
  12.  
  13. Connect the coil wiring.
  14.  



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Fig. Ignition coil test on the Trooper and Rodeo with V6 engines

COIL REMOVAL AND INSTALLATION
G180Z, G200Z and 4ZC1-T Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the ignition coil, condenser and transistor leads.
  4.  
  5. Remove the coil and bracket assembly. Remove the bracket assembly from the coil.
  6.  

To install:

  1. Install the bracket to the coil and tighten the retaining screw.
  2.  
  3. Install the assembly to the vehicle and torque the mounting bolts to 15 ft. lbs. (20 Nm).
  4.  
  5. Reconnect all electrical connectors and battery cable.
  6.  
  7. Check for proper operation.
  8.  

1986 and 1989 I-Mark Non-Turbo (4XC1-U)
  1. Disconnect the negative battery cable.
  2.  
  3. Mark the distributor housing, cylinder block and rotor position for ease of installation.
  4.  
  5. Remove the distributor cap and disconnect the electrical connectors.
  6.  
  7. Remove the distributor from the vehicle.
  8.  
  9. Remove the two retaining screws and ignition coil.
  10.  

To install:

  1. Remove any sealing and packing adhering to the coil and housing.
  2.  
  3. Wash the coil clean with cleaning solvent.
  4.  
  5. Lightly apply RTV sealer to the areas around the coil.
  6.  
  7. Install the coil and tighten the retaining bolts.
  8.  
  9. Install the distributor as outlined in this Section.
  10.  
  11. Connect all electrical connectors and check operation.
  12.  



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Fig. RTV sealer application I-Mark (non-turbo)



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Fig. Distributor assembly I-Mark (non-turbo) 4XC1-U engine

I-Mark Turbo
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the ignition coil electrical connectors.
  4.  
  5. Remove the mounting bolts and coil assembly.
  6.  

To install:

  1. Install the coil and mounting bolts. Torque the bolts to 20 ft. lbs. (27 Nm).
  2.  
  3. Connect all electrical connectors and battery cable. Check for proper operation.
  4.  

4XE1 DOHC Turbo Impulse
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the intercooler and cover.
  4.  
  5. Label and mark the spark plug wires before removal. Remove the ignition coil cover and spark plug wires.
  6.  
  7. Remove the ignition coil by removing the two retaining screws from the module. Be careful not to damage the module.
  8.  

To install:

  1. Install the coil and torque the screws to 40 inch lbs. (4.5 Nm).
  2.  
  3. Install the spark plug wires to their original locations.
  4.  
  5. Install the coil cover and intercooler.
  6.  
  7. Connect the negative battery cable and check operation.
  8.  



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Fig. Ignition coil removal 4XE1 DOHC turbo

Amigo, P'UP, Trooper, Trooper II with 4ZD1 and 4ZE1 Engines
  1. Disconnect the negative (-) battery cable and coil connectors.
  2.  
  3. Remove the two retaining screws and coil assembly.
  4.  
  5. Install the assembly and tighten the bolts.
  6.  
  7. Reconnect the electrical connectors and battery cable.
  8.  



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Fig. Ignition coil Amigo, Trooper and P-up with 4-cyl. engines

Trooper, Trooper II and Rodeo with V6 Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the ignition coil electrical connectors.
  4.  
  5. Remove the mounting bolts and coil assembly.
  6.  

To install:

  1. Install the coil and mounting bolts. Torque the bolts to 20 ft. lbs. (27 Nm).
  2.  
  3. Connect all electrical connectors and battery cable. Check for proper operation.
  4.  

 
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