Symptom Troubleshooting [Non-Hybrid Engine): Backfires

BACKFIRES REFERENCE CHART

8	BACKFIRES
DESCRIPTION	Sound produced from exhaust system

DTC DETECTION CONDITION POSSIBLE COUSES CHART

STEP	INSPECTION		ACTION
1	PRELIMINARY CHECKS Carry out the following preliminary checks: Vacuum lines (check for damage and correct routing). Spark plug wire routing (correct firing order). Are all checks OK?	Yes	GO to the next step.
1		No	REPAIR as required. VERIFY symptom no longer exists.
2	CARRY OUT PCM QUICK TEST See PCM QUICK TEST . Are any DTCs displayed during Continuous Memory, Key ON, Engine OFF (KOEO), Engine OFF (KOEO) or Key ON, Engine OFF (KOEO), Engine Running (KOER) Self-Tests?	Yes	CHECK for cause. See DTC INDEX - PCM .
2		No	GO to the next step.
3	CHECK SECONDARY IGNITION SYSTEM Is a strong blue spark visible at each disconnected high-tension lead while cranking engine?	Yes	CHECK spark plugs. If OK, GO to the next step. If not OK, CLEAN or INSTALL new spark plugs. See SPARK PLUGS REMOVAL/INSTALLATION - 2.5L or SPARK PLUGS REMOVAL/INSTALLATION - 3.0L .
3		No	GO to the next step.
4	CHECK FUEL DELIVERY SYSTEM Carry out fuel pressure inspection. See TEST 8: FUEL LINE/FUEL PRESSURE HOLD INSPECTION . Fuel line pressure: 240 - 380 kPa (35 - 55 psi). Is fuel pressure correct?	Yes	GO to the next step.
4		No	If pressure is greater than 380 kPa (55 psi): INSTALL a new fuel pump module. See FUEL PUMP MODULE REMOVAL/INSTALLATION . If pressure is less than 240 kPa (35 psi): CHECK fuel supply line for restriction.
5	CHECK FUEL DELIVERY SYSTEM Check fuel pump fuel flow. See TEST 7: FUEL PUMP INSPECTION . Did fuel system flow the required amount of fuel?	Yes	CHECK injector for leakage. See TEST 9: FUEL INJECTOR INSPECTION . If injector leaks, REPAIR as necessary. See FUEL RAIL REMOVAL/INSTALLATION - 2.5L or FUEL RAIL REMOVAL/INSTALLATION - 3.0L 01-14A-29. If injector OK, GO to the next step.
5		No	CHECK fuel supply line for restriction.
6	CHECK BASE ENGINE Check for base engine concerns (such as improper compression, worn camshaft/valve train, gasket leaks). Is a fault indicated?	Yes	REPAIR as required.
6		No	GO to the next step.
7	CHECK EXHAUST SYSTEM Is there a restriction in the exhaust system?	Yes	REPAIR as required.
7		No	VERIFY test results. If OK, See DIAGNOSTIC INDEX to repair any additional symptoms.