Coil Wiring

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The coil was first up in the wiring sequence. This is the stock Ford part with the oval connector port. The coil assembly, including new plug leads, totaled $205.81.  I re-used the old mounting bracket.

NGK 6510 Iridium IX plugs were recommended. $9.95 each.


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Hand drawn wiring diagram regarding coil wiring. M01 goes to the pin to the left (looking into the coil). Power comes into the center pin of the coil from Pin 87 on the Ignition Relay. The coil pin to the right is for the signal wire coming from M04.

The Zetec powerplant operates on what I learned was the “wasted spark” process. Two coils fire all four spark plugs. One cylinder is firing when it is supposed to, while another cylinder is firing at the exact same time but on the exhaust stroke. Since that other firing is on the exhaust stroke the perspective is that there is no harm in “wasting” that spark.


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The coil connector is a stock Ford part. The part number is 3U2Z-14S411-TNA. $77.00 with the pigtails. Picked up the “write-on” heat shrink at Home Depot. Helped in ready identification during the what-wires-go-where process.

Also visible here are the clear heat shrink butt connectors used to connect up the pigtail wires to the wires coming from the ECU. These fabulous little connectors are color coded for correct matching with various wire sizes. The color code band is placed at the recommended crimp point. After crimping you can see, through the clear covering, the actual positioning of the wire and the result of the crimping. And when the heat gun is applied, the clear covering shrinks to fit and an adhesive material is released to seal the connector around the wire.   These are available from Del-City. They also provide two-to- one, multi wire, clear cover, shrink tube butt connectors where one side is larger than the other (say 20-18 gauge on one end and 16-14 gauge on the other). Perfect for two-to-one splices.  And the Del-City web site has instructional videos.


Next Chapter: Injector Wiring