3 42 ELECTIl CAL VI Ignition System Illaqnnsls Guida Condition Possible Cause Correction MOMENTARY 1 Excessive resistance in ignition 1 Perform checks outlined in Ignition INTERRUPTION feed circuit System Tests Repair as needed OF IGNITION 2 Excessive resistance in coil 2 Perform checks outlined in Ignition primary circuit System Tests Repair as needed 3 Excessive resistance in coil 3 Perform checks outlined in Ignition secondary circuit System Tests Repair as needed 4 Excessive resistance in sensor 4 Perform checks outlined in Ignition circuit System Tests Replace sensor and modify connector terminals as needed 5 Electronic Control Unit Faulty 5 Replace ECU and modify connector terminals as outlined in Ignition System Tests ENGINE FAILS TO 1 No voltage to ignition system 1 Check battery ignition switch and START NO SPARK wiring Repair as needed AT PLUGS 2 Electronic Control Unit ground 2 Clean tighten or repair as needed lead open loose or corroded 3 Excessive resistance in primary 3 Perform checks as outlined in ignition circuit Ignition System Tests Repair as needed 4 Ignition coil open or shorted 4 Test coil Replace if faulty 5 Electronic Control Unit Faulty 5 Replace Electronic Control Unit and modify connector terminals as out lined in Ignition System Tests 6 Control Unit 4 wire connector 6 Clean with Jeep fabric cleaner and corroded or loose modify connector terminals as outlined in Ignition System Tests 7 Faulty sensor 7 Check resistance of sensor circuit as outlined in Ignition System Tests Replace if faulty ENGINE BACKFIRES 1 Incorrect ignition timing 1 Check timing Adjust as needed BUT FAILS TO START 2 Moisture in distributor cap 2 Dry cap and rotor