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Home >> GMC >> 2003 >> Jimmy 2D Utility, Part Time, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing - 4.3L >> Fuel Systems >> Fuel Injector Coil Test >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Observe Engine Coolant Temperature (ECT) parameter with scan tool. Is ECT value within 50-90°F (10-32°C)? If yes, go to next step. If no, go to step  4.
  3. On Astro and Safari, remove engine cover. On all models, disconnect the multi-way harness connector of the fuel injectors. Using a DVOM, measure resistance of each fuel injector between the ignition 1 circuit and the fuel injector control circuit, at the multi-way connector. Is resistance within the 11-14 ohms for each injector? If yes, go to FUEL INJECTOR BALANCE TEST WITHOUT SPECIAL TOOL  or FUEL INJECTOR BALANCE TEST WITH TECH 2  . If no, go to step  6.
  4. On Astro and Safari, remove engine cover. On all models, disconnect the multi-way harness connector of the fuel injectors. Using DVOM, measure the resistance of each fuel injector between the ignition 1 voltage circuit and the fuel injector control circuit, at the multi-way connector. Record each fuel injector resistance value. Subtract the lowest resistance value from the highest resistance value. Is difference equal to or less than 3 ohms? If yes, go to FUEL INJECTOR BALANCE TEST WITHOUT SPECIAL TOOL  or FUEL INJECTOR BALANCE TEST WITH TECH 2  . If no, go to next step.
  5. Add all fuel injector resistance values to obtain a total resistance value. Divide total resistance value by number of fuel injectors to obtain an average resistance value. Subtract lowest and highest individual fuel injector resistance values from average resistance value. Replace fuel injector that displays greatest resistance difference, more or less than average. After repairs, go to step  7.
  6. Replace fuel injector(s) that are outside of 11-14 ohms range. After repairs, go to next step.
  7. Operate system in order to verify repair. Did you correct the condition? If yes, system is okay. If no, go to step  2.
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