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2G Wiring in PTU pigtail

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v8s_are_slow

20+ Year Contributor
2,823
266
Sep 30, 2002
Panama City, Florida
I deleted my ptu due to issues I was having and going with a M&W ignition and coil-on plug setup. However, I think the M&W might be having issues and so want to send it off for inspection and use stock coils instead. But can someone please verify if this is correct on wiring it back in so I don't burn up (another one) my ecu please? Thank you!!!
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This is the stock 2G Ignition circuit. It looks like it matches.

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As you should be able to see here, the Brown/Red wire from the ECU pin 23 goes to Pin 2 on the PTU for Cyls 2 & 3.
The Black/Blue wire from ECU pin 10 goes to Pin 7 on the PTU for Cyls 1 & 4.
The Blue/Black wire from the Cyls 2 & 3 Coil goes to Pin 1 on the PTU.
The Blue/Red wire from the Cyls 1 & 4 Coil goes to the ignition check connectoor on the firewall where it changes to a Black/White wire and goes to Pin 8 on the PTU.
That leaves the Tach, Power and Ground to connect. You can tell where those go.
 
So I'm a bit confused on the black/white power wire at the moment. Right "now" on the coil plug, I have 12 volts on the bottom wire, with no ptu. So if I were to cut that wire and connect to the ptu plug instead to deliver that power, then how does the coil plug now get power???
 
Didn't trust me LOL?
Heck, I'm getting feedback from everywhere I can to make sure I understand this crap. Lol. Not understanding it is how ecu's get burned up.....again. And I still don't know what to do with that power wire at the moment. Only place I'm getting 12 volts right now is at the coil plug. So guess I'm missing a power wire somewhere?!?!?!?
 
The +12v only goes to one side the coils primary. The other side of the coils primary is switched to and from ground by the PTU to energize the coil (think of it as turning the coil on and off). The coil's magnetic field builds up while the coil is activated (switched to ground so current flows through the primary). Then when the ground is removed (switched off by the PTU) the magnetic field collapses across the coil secondary and generates the very high voltage spark in it to go to one spark plug pair.
 
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The +12v only goes to one side the coils primary. The other side of the coils primary is switched to and from ground by the PTU to energize the coil (think of it as turning the coil on and off). The coil's magnetic field builds up while the coil is activated (switched to ground so current flows through the primary). Then when the ground is removed (switched off by the PTU) the magnetic field collapses across the coil secondary and generates the very high voltage spark in it to go to one spark plug pair.
Right, but the problem I have is that I have 12 volts at the coil plug. But if I have to also connect a wire to the ptu that's 12 volts, I'm unable to find where that wire is that supplies 12 volts.
 
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