Fuel Injector: Testing and Inspection

Fuel Injector Test

NOTE: Check the following items before testing: idle speed, ignition timing and idle CO%.

If the engine will run:
1. With the engine idling, disconnect each injector connector individually and inspect the change in the idling speed.
- If the idle speed drop is almost the same for each cylinder, the injectors are normal.
- If the idle speed or quality remains the same when you disconnect a particular injector, replace the injector and re-test.





2. Check the clicking sound of each injector by means of a stethoscope when the engine is idling.
- If any injector fails to make the typical clicking sound, check the sound again after replacing the injector.
- If clicking sound is still absent, check the following:
- Whether there is any short-circuiting, wire breakage or poor connection in the Yellow/Black wire between the main relay and the resistor.
- Whether the resistor is open or corroded.
- Whether there is any short-circuiting, wire breakage or poor connection in the Red/Black wire between the resistor and the injector.
- Whether there is any short-circuiting, wire breakage or poor connection in the wire between the injector and the ECU.
If all is OK, check the ECU.

If the engine cannot be started:





1. Remove the connector of the injector, and measure the resistance between the 2 terminals of the injector.

Resistance should be: 1.5 - 2.5 Ohms

- If the resistance is not as specified, replace the injector.
- If the resistance is as specified, check the fuel pressure.
- If the fuel pressure is as specified, check the following:
- Whether there is any short-circuiting, wire breakage or poor connection in the Yellow/Black wire between the main relay and the resistor.
- Whether the resistor is open or corroded.
- Whether there is any short-circuiting, wire breakage, or poor connection in the Red/Black wire between the resistor and the injector.
- Whether there is any short-circuiting, wire breakage or poor connection in the wire between the injector and the ECU.
- If all is OK, check the ECU.