Fuel Injector Coil Test

Verify the resistance of each fuel injector with one of the following methods:

• If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14 ohms.
  • If the injectors measure OK, perform the Active Fuel Injector Tester (AFIT) Test Procedure.
  • If not within the specified range, replace the fuel injector.
• If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms.
  • If the difference is equal to or less than 3 ohms, refer to Fuel Injector Coil Test .
  • If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

AFIT Test Procedure

1. Turn OFF all accessories.
2. Turn OFF the ignition.
3. Install the AFIT. Refer to the AFIT User Guide.
4. Turn ON the AFIT and select the vehicle.
5. Turn ON the ignition and perform the Injector Test.
   • If the AFIT aborts testing due to fuel pressure or fuel leak down, refer to Fuel System Diagnosis .
6. View the test results.
   • If any injector exceeds the recommended tolerance, replace the injector(s), E-85 only. All other engine, refer to Fuel Injector Cleaning .