Non Trouble Code Components

System Schematic:

To test the Injectors, located in the injection mixer chamber, proceed as follows.


OSCILLOSCOPE TEST

Oscilloscope Pattern:

1. Run the engine until it reaches operating temperature. Maintain idle speed for testing.
2. Connect the scope pick-up probe to the test points shown in the system schematic. Compare the scope pattern to the image shown. If scope pattern is not as depicted in image, continue with the rest of the test procedures before replacing the assembly.





FUNCTIONAL TEST

Operational Test:

Using a stethoscope, check the operational sound (tick) made by the injector during idle or cranking. Check that the sound is produced at shorter intervals as the engine speed increases.

Injector Operating State

Engine State Injector Connector Color Operating Sound

Cranking Black Heard
Blue Not Heard
Idling Black Heard
Blue Not Heard
Racing Black Heard
Blue Heard

CAUTION: Other injectors may produce sound as they operate even if the injector being tested does not operate. Ensure that the sound from an adjacent injector is not being transmitted to an inoperative injector.

Injector Test:

RESISTANCE MEASUREMENT BETWEEN TERMINALS:
1. Disconnect the connector for the injector.
2. Measure the resistance between the terminals.

Standard Value...2-3 ohm (20°C/68°F)


RESISTOR TEST

Resistor Test:

Disconnect the resistor connector. Measure the resistance between the terminals listed below.

Terminals Resistance
1 - 2 5.5 - 6.5 Ohms
1 - 3 at 20°C (68°F)

If the resistance is not within the specified rating, the assembly needs to be replaced.

HARNESS TEST

1. Disconnect the injector connector and turn on the ignition.
2. Using a voltmeter, measure the power supply voltage between each injector harness connector terminal 2 and ground.

Voltage: Approx 8 Volts.

1. Turn off the ignition. Disconnect the resistor connector and turn on the ignition.
2. Using a voltmeter, measure the power supply voltage between ground and the resistor harness connector terminal 2 and 3.

Voltage: System Voltage.


3. Turn off the ignition and disconnect the ECU connector. Using an Ohmmeter, check for continuity (short) to ground, between the injector harness connector terminal 1 and the ECU harness connector terminals 60 and 62.

Continuity: Should Not Exist.

4. Using an Ohmmeter, check for continuity between injector harness connectors terminal 1 and the ECU harness connector terminals 60 and 62.

Continuity: Should Exist.


If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, road test the vehicle to confirm that the repair has corrected the problem.
If the same problem reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.