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Home >> Isuzu >> 2007 >> i-290 LS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 86 (Engine Control System & Fuel System - 3.7L - Diagnosis & Troubleshooting) >> Fuel Injector Diagnosis (w/CH47976) >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2007 Isuzu i-370, 2007 GMC Canyon, and 2007 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

Fuel Injector Coil Test

  1. Observe the ECT Sensor parameter with a scan tool. The engine coolant temperature (ECT) sensor should be 10-32°C (50-90°F).
    • If the ECT Sensor parameter is not within 10-32°C (50-90°F), go to step 3.
  2. Measure the resistance of each fuel injector with a DMM. The resistance of each fuel injector should be 11-14 ohms.
    • If the resistance of any fuel injector is not 11-14 ohms, replace the fuel injector.
  3. 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, perform the AFIT Test Procedure.
    • If the difference is more than 3 ohms, continue with the Fuel Injector Coil Test.
  4. 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 resistance difference above or below the average.
  5. Perform the AFIT Test Procedure.
IMPORTANT:
  • DO NOT perform this test if the 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.

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.
  6. View the test results.
    • If any injector exceeds the recommended tolerance, perform the following procedure:
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