Toyota Pick-ups/Land Cruiser/4Runner 1970-1988

Troubleshooting the Fully Transistorized Electronic Ignition System

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PRECAUTIONS



  1. Do not allow the ignition switch to be ON for more than ten minutes if the engine will not start.
  2.  
  3. When a tachometer is connected to the system, always connect the tachometer positive lead to the ignition coil negative terminal. As some tachometers are not compatible with this system, it is recommended that you consult with the manufacturer.
  4.  
  5. NEVER allow the ignition coil terminals to touch ground as it could result in damage to the igniter and/or the ignition coil itself.
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  7. Do not disconnect the battery when the engine is running.
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  9. Make sure that the igniter is always properly grounded to the body.
  10.  

TROUBLESHOOTING



See Figure 1

Troubleshooting this system is easy, but you must have an accurate ohmmeter and voltmeter. The numbers in the diagram correspond to the numbers of the following troubleshooting steps. Be sure to perform each step in order.

  1. Check for spark at the spark plugs by hooking up a timing light in the usual manner. If the light flashes, it can be assumed that voltage is reaching the plugs, which should then be inspected, along with the fuel system. If no flash is generated, go on to the following ignition checks.
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Click image to see an enlarged view

Fig. Fig. 1: Troubleshooting the electronic ignition system

  1. Check all wiring and plastic connectors for tight and proper connections.
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  3. (1) With an ohmmeter, check between the positive (+) and negative (-) primary terminals of the ignition coil. The resistance (cold) should be 1.3-1.7-. Between the (+) primary terminal and the high tension terminal, the resistance (cold) should be 12-16k-.(2) The insulation resistance between the (+) primary terminal and the ignition coil case should be infinite.
  4.  
  5. The resistor wire (brown and yellow) resistance should be 1.2- (cold). To measure, disconnect the plastic connector at the igniter and connect one wire of the ohmmeter to the yellow wire and one to the brown.
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  7. Remove the distributor cap and ignition rotor.(1) Check the air gap between the timing rotor spoke and the pick-up coil. When aligned, the air gap should be 0.008-0.016 in.. You will probably have to bump the engine around with the starter to line up the timing rotor.(2) Unplug the distributor connector at the distributor. Connect one wire of the ohmmeter to the white wire, and one wire to the pink wire. The resistance of the signal generator should be 130-190-.
  8.  
  9. (1) Checking the igniter last, connect the (-) voltmeter wire to the (-) ignition coil primary terminal, and the (+) voltmeter wire to the yellow resistor wire at the connector unplugged in Step 4. With the ignition switch turned to On (not Start) the voltage should measure 12 volts. (2) Check the voltage between the (-) ignition coil primary terminal and the yellow resistor wire again, but this time use the ohmmeter as resistance. Using the igniter end of the distributor connector unplugged in Step 5, connect the positive (+) ohmmeter wire to the pink distributor wire, and the negative (-) ohmmeter wire to the white wire.
  10.  


CAUTION
Do not intermix the (+) and (-) terminals of the ohmmeter.

Select either the 1- or 10- range of the ohmmeter. With the voltmeter connected as in Step 6 (1), and the ignition switch turned to On (not Start), the voltage should measure nearly zero.

 
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