For 1990-2009 cars

## Backfire Petrol

Checks | Action
--- | ---
DEFINITION: The fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Preliminary Checks | Refer to Important Preliminary Checks in Symptoms - Engine Controls .
Ignition System Checks |

• | Remove and inspect the spark plugs for the following conditions:

- | Wet plugs

- | Cracks

- | Wear

- | Incorrect gap

- | Burned electrodes

- | Heavy deposits

• | Test for correct ignition system operation.

• | Test for crossfire between spark plugs. Test for spark plug wire failure.

Engine Mechanical Checks |

• | Inspect the engine for the following:

- | Intake manifold leaks

- | Incorrect valve timing

- | Correct engine cylinder compression

- | Sticking or leaking intake or exhaust valves

- | Exhaust system leakage

• | Inspect the intake and exhaust system for casting flash.

Fuel System Checks | Perform fuel system diagnosis. Refer to Fuel System Diagnosis .
Additional Checks |

• | Review service bulletins for LPG ECM PCM programming updates.

• | Verify that the correct LPG software and calibration has been programmed into the LPG ECM.

• | Test for correct operation of the AFO Enable circuit.