Component Testing

Fuel Injector Coil Static 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 Ω.
  • If the injectors measure OK, perform the Fuel Injector Balance Test and the Fuel Pressure Test.
  • 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 two should be equal to or less than 3 Ω.
  • If the difference is equal to or less than 3 Ω, refer to Fuel Pressure Measurement  for further diagnosis of the fuel injectors.
  • If the difference is more than 3 Ω, 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.

Fuel Pressure Test

NOTE:
• DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
• Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
• Before proceeding with this test review the User Manual CH-48027-5 for Safety Information and Instructions.
1. Install a fuel pressure gauge. Refer to Fuel Pressure Measurement .
2. Turn ON the ignition, with the engine OFF.
NOTE:
• The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
• DO NOT start the engine.
3. Command the fuel pump relay ON with a scan tool.
4. Observe the fuel pressure gauge with the fuel pump relay commanded ON. The fuel pressure should be 345-414 kPa (50-60 PSI).
   • If the fuel pressure is not 345-414 kPa (50-60 PSI), refer to Fuel System Diagnosis .
5. Monitor the fuel pressure gauge for five minutes. The fuel pressure should not decrease more than 34 kPa (5 PSI).
   • If the fuel pressure decreases more than 34 kPa (5 PSI), refer to Fuel System Diagnosis .