MAZDA TRIBUTE/FORD ESCAPE V6 – MISFIRE AFTER REPLACING SPARK PLUG OR IGNTION COILS The initial cause of misfire may be a result of a malfunctioning spark plug or ignition coil, but, the problem compounds when the electrical harness that connects the coils to the engine control unit and power supply is incorrectly re-­‐fitted on reassembly. This problem is generally experienced when replacing spark plugs and [or] ignition coils on the front bank [closest to the radiator, cylinders 2, 4, 6]. Symptoms •
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Misfire from cylinder’s number 4 and 6 after spark plug and [or] coil replacement. Backfire from inlet and exhaust. Runs rough. High exhaust temperature. Problem -­‐ The wiring harness may have been incorrectly fitted to ignition coils 2, 4, 6 The coil connectors are ambidextrous. The most common mistake is connecting cylinder No. 4 to No. 6 ignition coil and respectively cylinder No.6 connector to No. 4 ignition coil resulting in incorrect ignition phasing. Note: The above image is provided as a reference guide only and outlines in general terms the correct wiring routing. Always consult manufacturer’s information resources for clarification. Test Procedure •
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Test the ignition coil power supply using a multimeter [Ignition On, Battery Supply Voltage to positive terminal of ignition coil]. Test the ignition coil negative trigger using an LED test light [Check for primary ignition pulse]. Check wiring routing to the corresponding ignition coils and verify correctness. Note: Ensure to check for air leaks around the inlet manifold, air leaks are symptomatic with engine misfires, this is a common occurrence. Remedy Correctly connect wiring to the corresponding ignition coils as required, The wiring colour scheme for each ignition coil is as follows:-­‐ •
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Cylinder #1 – supply white/pink and negative [Ignition Pulse] green/white Cylinder #2 – supply white/pink and negative [Ignition Pulse] green/purple Cylinder #3 – supply white/pink and negative [Ignition Pulse] orange/yellow Cylinder #4 – supply white/pink and negative [Ignition Pulse] white/red Cylinder #5 – supply white/pink and negative [Ignition Pulse] pink/white Cylinder #6 – supply white/pink and negative [Ignition Pulse] green yellow C9314 MAZDA TRIBUTE Locate your nearest dealer click here MAKE FAULT FINDING EASY OTC D730 OE LEVEL COVERAGE FOR AUSTRALIAN, ASIAN,
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