Toyota Cressida/Corona/Crown/MarkII 1970-1982 Repair Guide

Transistorized Ignition System

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Fig. Fig. 1 Schematic of the fully transistorized ignition system-1980 federal models



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Fig. Fig. 2 Schematic of the fully transistorized ignition system-1980 California and Canada models

Troubleshooting the fully transistorized ignition system is easy, but you must have an accurate ohmmeter and voltmeter and take certain precautions as follow.

PRECAUTIONS



  1. Do not allow the ignition switch to be ON for more than 10 minutes if the engine will not start.
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  3. Some tachometers are not compatible with the fully transistorized system. Check the tach's instruction sheet or its manufacturer if there is any doubt in your mind about compatibility.
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  5. When connecting a tachometer: On USA models, connect the tachometer (plus) terminal to the ignition coil (minus) terminal. On some Canadian models a service wiring connector (covered with a rubber boot) is provided for tachometer connection.
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  7. Never allow the ignition coil terminals to touch ground. Damage to the ignitor or coil could result if the terminals are grounded.
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  9. Do not disconnect the battery when the engine is running.
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  11. Make sure that the ignitor is properly grounded to the body.
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TESTING



Before testing the signal generator and the ignitor, several other ignition system components should be checked.

  1. Connect a timing light to each plug wire in turn. Crank the engine, if the light flashes it can be assumed that voltage is reaching the plugs. If there is no flash from the timing light, see Step 2.
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  3. Inspect the spark plug wires. Carefully remove the wires from the spark plugs by twisting the boots. Do not pull or bend the wire, damage to the inside conductor will occur. Inspect the terminals for dirt, looseness and corrosion. If the outside insulation is cracked or broken, replace the wire. Check the resistance of the wire with an ohmmeter. Do not disconnect the wire from the distributor cap. Remove the distributor cap, connect one lead of the ohmmeter to the distributor cap contact and the other to the terminal of the connected plug wire. Replace any wires with excessive resistance, over 8000 omega per foot of cable length (more than 25 kilo-ohms), or any that have no continuity. Inspect the distributor cap and ignition rotor for cracks, damage or carbon tracking. Replace as necessary.
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  5. Remove the spark plugs and check for electrode wear, carbon deposits, thread damage and insulator damage. If any problem is found, replace the plugs. If the old plugs are to be reused, clean them with a wire brush or have them cleaned in a spark plug cleaner. (Check your local gas station). After cleaning the plugs, check the gap and reinstall.
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If the engine still will not start, or the timing light test shows no spark, check the ignition coil resistances.

Ignition Coil
PRIMARY RESISTANCE

With an ohmmeter, check between the positive (plus) and negative (minus) terminals of the ignition coil. With the coil cold, the resistances should be:

1977-79 All models: 1.3-1.7 omega

1980 Fed. models: 0.5-0.6 omega

1980 Canada & Calif.: 0.8-1.0 omega

1981 22R engine: 0.8-1.0 omega (USA)

1981 Canada: 0.4-0.5 omega

1981 5M-E engine: 0.5-0.6 omega

SECONDARY RESISTANCE

With an ohmmeter, check between the positive (plus) coil terminal and the high tension (coil wire) terminal. Clean the coil wire terminal with a wire brush before testing. The resistance on all models except 1981 and later Canadian models should be 11.5-15.5k omega ; Canadian models (1981 and later): 8.5-11.5k omega .

Ballast Resistor/Resistor Wire

On models with a coil mounted resistor, connect the ohmmeter leads to the end terminals of the resistor. Resistance should measure 1.2-1.4 omega . On models with a resistor wire, disconnect the plastic connector at the igniter. Connect one ohmmeter lead to the yellow wire and the other to the brown wire. Resistance should measure 1.2-1.4 omega .

If the tests on the coil or the resistor show values far from the standard, replace the part or wire, perform the timing light test or attempt to start the engine.

Checking the Air Gap

Remove the distributor cap and ignition rotor. Check the air gap between the timing rotor spoke and the pick up coil. When aligned, the air gap should be 0.2-0.4mm. You will probably have to bump the engine around with the starter to line up the timing rotor. Refer to air gap adjustment in for adjustment procedure.

Signal Generator (Pickup Coil)

Check the resistance of the signal generator. Unplug the connector to the distributor. Connect one lead of the ohmmeter to the white wire, the other lead to the pink wire. Resistance should be 130-190 omega . If resistance is not correct, replace the signal generator.

Igniter
ALL 1977-80 MODELS AND 1981 CANADIAN
  1. Connect the negative (minus) probe of the voltmeter to the negative (minus) terminal of the ignition coil and the positive (plus) probe of the voltmeter to the yellow resistor wire at the connector unplugged from the ignitor. With the ignition switch ON (not start) the voltage should read 12 volts.
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  3. Check the voltage between the negative (minus) coil terminal and the yellow resistor wire again, but this time use the ohmmeter as resistance. Connect the positive (plus) ohmmeter lead to the pink wire in the plug connector. Connect the negative (minus) ohmmeter lead to the white wire in the connector.
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WARNING
Do not reverse the connection of the ohmmeter.

Select either the 1 omega or 10 omega range on the ohmmeter. With the voltmeter connected as in Step one and the ignition switch turned ON, the voltage should measure nearly zero. If a problem is found, replace the ignitor.

1981 MODELS (EXCEPT CANADA)
  1. Connect the positive (plus) probe of the voltmeter to the positive (plus) terminal of the ignition coil. Connect the negative (minus) probe of the voltmeter to the car body ground. Turn the ignition switch to the ON position. The voltage should read 12 volts.
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  3. To check the power transistor in the ignitor, connect the positive (plus) probe of the voltmeter to the negative (minus) terminal of the ignition coil and the negative (minus) probe of the voltmeter to the car body ground. Turn the ignition switch to the ON position. The reading should be 12 volts.
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  5. Unplug the wiring connector from the distributor. With a 1.5 volt dry cell battery in circuit, i.e. connect the positive pole of the battery to the pink terminal of the connector plug, and the negative pole of the battery to the white wire. Connect the voltmeter with the positive (plus) probe connected to the negative (minus) terminal of the ignition coil and the negative (minus) probe of the voltmeter to the car body ground. Turn the ignition switch to the ON position. Voltage should measure 5 volts, less than battery voltage.
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WARNING
Do not apply voltage for more than five seconds or the power transistor will be destroyed.

If a problem is found, replace the ignitor.

REMOVAL & INSTALLATION





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Fig. Fig. 3 On some models the igniter is attached to the ignition coil on the firewall

Igniter

The igniter is mounted on either the firewall separately or attached to the ignition coil.

  1. Disconnect the negative battery cable.
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  3. Tag and disconnect the wires attached to the igniter.
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  5. Unbolt or unscrew the igniter from its mounting place.
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To install:

  1. Attach the wiring to the igniter.
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  3. Place the igniter into position and tighten the mounting bolts or screws.
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  5. Connect the negative battery cable.
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Pickup Coil

Remove the distributor cap and ignition rotor. Disconnect the distributor wiring connector. Remove the two screws that mount the signal generator (pickup coil). Install the new signal generator with the two mounting screws, do not completely tighten the screws until you have adjusted the air gap. (See air gap adjustment, ). Reconnect the wiring harness, install the rotor and distributor cap. Check for engine starting. If the engine will not start, check the ignitor.

 
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