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Home >> Isuzu >> 1998 >> Trooper LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Trouble Shooting - Hombre 4.3L >> Engine Cranks But Will Not Start >> Ignition System

Ignition System

  1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in TESTS W/CODES - INTRODUCTION article. After performing OBD-II system check, go to next step.
  2. Install Tech 2 scan tool. Using scan tool, monitor Throttle Position (TP) sensor. Ensure is throttle closed. If TP sensor value is greater than 2.5 volts, diagnose using DTC P0123. See appropriate TESTS W/CODES - INTRODUCTION article. If TP sensor voltage is less than 2.5 volts, go to next step.
  3. Using scan tool, monitor Engine Coolant Temperature (ECT) sensor. If ECT sensor value is less than -22°F (-30°C), diagnose using DTC P0118. See appropriate TESTS W/CODES - INTRODUCTION article. If ECT sensor is greater than specified, go to next step.
  4. Turn ignition off for 10 seconds. Turn ignition on. Fuel pump should operate for about 2 seconds. If fuel pump operates as specified, go to next step. If fuel pump does not operate as specified, go to FUEL SYSTEM.
  5. Turn ignition off. Disconnect injector harness connector at intake manifold. Using a test light connected to ground, probe injector feed circuit. See WIRING DIAGRAMS article. Turn ignition on with engine off. If test light flashes, go to next step. If test light does not flash, go to step 8).
  6. Disconnect one spark plug wire. Install Spark Tester (J-26792). Crank engine. If spark is present, go to next step. If spark is not present, diagnose enhanced ignition system. See TESTS W/CODES - INTRODUCTION article.
  7. Reconnect spark plug wire. Turn ignition off. Connect fuel pressure gauge. Turn ignition on with engine off. Observe fuel pressure. Fuel pressure should be 55-61 psi (3.9-4.3 kg/cm2 ). If fuel pressure is as specified, perform fuel injector balance test. See INJECTOR BALANCE TEST under FUEL SYSTEM in I - SYSTEM & COMPONENT TESTS article. If fuel pressure is not as specified, diagnose fuel system. See FUEL SYSTEM DIAGNOSIS.
  8. Repair injector ignition feed circuit. See WIRING DIAGRAMS article. After repairs, go to next step.
  9. Using scan tool, select DTC, CLEAR INFO function. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and dies, go to step 2).
  10. Warm engine to normal operating temperature. Using scan tool, select DTC, FAILED THIS IGN function. If DTC(s) are displayed, diagnose DTC(s). See TESTS W/CODES - INTRODUCTION article. If DTC(s) are not present, go to next step.
  11. Select CAPTURE INFO, REVIEW INFO function. If additional DTC(s) are displayed, diagnose DTC(s). See TESTS W/CODES -INTRODUCTION article. If DTC(s) are not present, system is okay.
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