ElvisDrivesAnMK
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| posted on 8/8/12 at 10:20 PM |
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ST170 Coil Wires
There are three wires coming from the coil on my Mk1 Focus ST170 engine (running standard fuel injection with a Megasquirt ECU) sitting in my MK Indy
R:
Orange and black
Green and blue
Green and black
Does anyone know what purpose in life these all have?
Thanks in advance,
Elvis
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coozer
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| posted on 8/8/12 at 10:31 PM |
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Yep, they serve the coil with info for sending volts to the spark plugs.
1972 V8 Jago
1980 Z750
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Dusty
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| posted on 8/8/12 at 10:39 PM |
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They are logically arranged. The zetec coil is two coils. looking at the plug on the coil the middle contact is ignition live, the left hand one fires
the left coil for 1/4 and the right hand wire fires the right coil for 2/3. Wasted spark.
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ElvisDrivesAnMK
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| posted on 8/8/12 at 11:07 PM |
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Thanks for the replies. More specifically which wire is the switched negative or am I missing something?
Thanks,
Elvis.
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coozer
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| posted on 8/8/12 at 11:24 PM |
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Middle one is 12v live, 1 & 3 are switched by the MS
No negatives.
[Edited on 8/8/12 by coozer]
1972 V8 Jago
1980 Z750
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big-vee-twin
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| posted on 9/8/12 at 04:40 PM |
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MS switches the two outer pins to earth, these are the ones you connect to pins 32/33 & 34/35 on the MS.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
http://www.triangleltd.com
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MikeRJ
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| posted on 9/8/12 at 04:49 PM |
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If you want to drive a tachometer from a wasted spark coil like the Ford one, then you will need to add a small amount of
external circuitry.
Simply hooking up the tacho to one of the switched coil connections will result in the tacho reading half the engine speed.
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ElvisDrivesAnMK
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| posted on 10/8/12 at 12:52 PM |
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Thanks for the responses everyone. I'm going to try a couple of things this weekend and will let you know how I get on.
Cheers,
Elvis.
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coozer
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| posted on 11/8/12 at 10:41 AM |
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Just a thought, are you using EDIS? Is the MS edis type or does it have its own coil drivers?
1972 V8 Jago
1980 Z750
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ElvisDrivesAnMK
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| posted on 13/8/12 at 03:08 PM |
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Easy Peasy
This turned out to be a very straightforward job:
1. Splice into the left wire for cylinders 1 & 4 and connect to the
SPA Tacho.
2. The SPA gauge expects one pulse for each cylinder so I set the "Number of Cylinders" setting on the Tacho gauge to 2 rather than 4 so
that it multiplies the number of pulses per sec by 2.
It took all of 5 minutes
Thanks again.
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