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Home >> Isuzu >> 2002 >> Axiom Base, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing >> Fuel System >> Fuel Injector Coil Test >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform On-Board Diagnostics II (OBD-II) System Check. See ON-BOARD DIAGNOSTICS II (OBD-II) SYSTEM CHECK under SELF-DIAGNOSTICS in appropriate SELF-DIAGNOSTICS article. After performing OBD-II system check, go to next step.
  2. Turn ignition off. To prevent flooding of engine, relieve fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Turn engine off. Disconnect fuel injector tester 5 or 7-pin in-line harness connector. In-line harness connector is located near front of valve cover and is identified by Blue locking plate. Connect Fuel Injector Tester (J 39021-5V) and Injector Switch Box (J 39021-90) to fuel injector harness. Connect DVOM leads to tester. On tester, set amperage supply selector to COIL TEST 0.5 amp position. If engine coolant temperature is between 50-90°F (10-35°C), go to next step. If engine coolant temperature is more than specified, go to step  5.
  3. Set injector switch box to injector No. 1. Press PUSH TO START TEST button. Observe voltage reading on DVOM. After one second, record lowest voltage observed on DVOM. Voltage reading should be 5.7-6.6 volts. Move injector switch box to next injector and repeat test until all injectors have been tested. If voltage is erratic and does not stabilize or is outside of specification at any injector, go to next step. If all injectors voltages test within specification, go to FUEL INJECTOR BALANCE TEST .
  4. Replace suspect fuel injector. See FUEL RAIL & FUEL INJECTORS in REMOVAL, OVERHAUL & INSTALLATION article.
  5. Set injector switch box to injector No. 1. Press PUSH TO START TEST button. Observe voltage reading on DVOM. After one second, record lowest voltage observed on DVOM. Voltage reading should be 9.5 volts. Move injector switch box to next injector and repeat test until all injectors have been tested. If voltage is erratic and does not stabilize or is more than specification at any injector, go to step  4. If all injectors voltages test within specification, go to next step.
  6. Observe recorded voltages. Identify highest voltage reading (other than those above 9.5 volts). Subtract voltage reading of other injectors from highest reading. If subtracted value is 0.6 volts or more, go to step  4. If subtracted values are as specified, go to FUEL INJECTOR BALANCE TEST .
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