CAUTION
Keep clear of sparks or flame during testing.
The simplest way to test the injectors is simply to listen to them with the engine running. Use either a stethoscope-type tool or the blade of a long screw driver to touch each injector while the engine is idling. You should hear a distinct clicking as each injector opens and closes.
| Fig. 1:Fuel injector testers can be purchased or sometimes
rented
|
| Fig. 2: Place the sound scope on the injector to inspect
for normal operation
|
If you have no sound scope, you can check the injector transmission operation with your finger. If no sound or unusual sound is heard, check the wiring connector, injector or injection signal form the ECM.
| Fig. 3: Place your finger over the injector if a scope
is not available
|
Additionally, the resistance of the injector can be easily checked. Disconnect the negative battery cable and remove the electrical connector from the injector to be tested. Use an ohmmeter to check the resistance across the terminals of the injector. Correct resistance is between 13.4–14.2 ohms at 68°F (20°C); slight variations are acceptable due to temperature conditions.
| Fig. 4: Testing the fuel injector with an ohmmeter
|
Never attempt to check a removed injector by hooking it directly to the battery. The injector runs on a much smaller voltage and the 12 volts from the battery will destroy it internally.
