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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1172 (Engine Controls - 6.0L - Alternative Fuels (Troubleshooting)) >> Troubleshooting >> Fuel Injector Coil Test >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  This step tests each fuel injector resistance within a specific temperature range. If any of the fuel injectors display a resistance outside of the specified value, replace the fuel injector.
  2. 4:  This step determines if all of the fuel injectors are within 0.5 ohms of each other. If the highest resistance value is within 0.5 ohms of the lowest resistance value, then all of the fuel injector coil windings are OK.
  3. 5:  This step determines which fuel injector is faulty. After subtracting the highest and lowest resistance values from the average value, replace the fuel injector that has the greatest resistance difference from the average.
Fuel Injector Coil Test

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check Alternative Fuels - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Alternative Fuels (Engine Controls)
2 Observe the engine coolant temperature (ECT) with a scan tool.
Is the ECT value within the specified range?		 10-32° C (50-90° F) Go to Step 3  Go to Step 4 
3 
NOTE: Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.
IMPORTANT: Calibrate the DMM and test leads to 0 Ohms in order to prevent misdiagnosis.
Measure the resistance of each CNG fuel injector with a DMM. Refer to Testing for Continuity in Wiring Systems in the C/K Truck Service Manual.Do any of the fuel injectors display a resistance outside the specified range?		 1-2 ohm Go to Step 6  Go to Diagnostic Aids
4 
NOTE: Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.
  1. Measure the resistance of each CNG fuel injector with a DMM. Refer to Testing for Continuity in Wiring Systems in the C/K Truck Service Manual.
  2. Record each fuel injector value.
  3. Subtract the lowest resistance value from the highest resistance value.
Is the difference equal to, or less than, the specified value?		 0.5 ohm Go to Diagnostic Aids Go to Step 5 
5 
  1. Add all of the CNG fuel injector resistance values, to obtain a total resistance value.
  2. Divide the total resistance value by the number of fuel injectors, to obtain an average resistance value.
  3. Subtract the lowest, and the highest, individual fuel injector resistance values from the average resistance value.
  4. Replace the CNG fuel injector that displays the greatest resistance difference, above or below the average. Refer to Fuel Injector Replacement .
Did you complete the replacement?		 - Go to Step 7  -
6 Replace the fuel injector or fuel injectors that are out of the specified range. Refer to Fuel Injector Replacement .
Did you complete the replacement?		 - Go to Step 7  -
7 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
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