Test 11 - Power Transistor Testing

TOP DEAD CENTER (TDC) SENSOR TEST


To test the Top Dead Center (TDC) Sensor located in the distributor, proceed as follows.

Distributor Connector:

OSCILLOSCOPE TESTING PROCEDURE:


1. Connect test leads from the oscilloscope to the Brown/Red wire of the distributor connector and run the engine at idle speed.

Scope Test Waveform--single Rotation Of The Distributor:

Check the waveform and compare it to the diagram shown. If scope pattern is not as depicted in image, continue with the rest of the test procedures before replacing the assembly.

VOLTAGE TESTING PROCEDURE:

1. Connect a voltmeter between the Brown/Red (+) wire and the Black (-) Wire of the distributor connector.
Brown/Red Wire: Top Dead Center (TDC) signal
Black Wire: Sensor ground

2. Measure the output voltage of the terminals while cranking the engine.
Standard Approximate Value

Terminal 4: 2.0 - 2.5v


3. If voltmeter readings are not as specified disconnect the distributor connector and check that the Black/White wire of the harness connector has near battery voltage with the ignition key in the ON position and that the Black wire of the distributor connector has very low resistance to ground. If test is as specified and there is still no output signal, replace the Top Dead Center (TDC) sensor. If power and grounds test properly and there is still no signal output, check controller signal.