Thread: Do P12 20v coil plugs have built in ignition modules?

All i can say is the factory b13 harness was kinda retarded the way it was routed. lol. Especially the knock sensor.

When i made my harness i took and used the shielded section and just shortened the wires to the length i needed them for the tucked harness.

Well, I'm done testing to my satisfaction with different options for getting a timing signal. From low to mid RPM I couldn't tell the difference with the timing light between getting the inductive signal from the coil ground wire (like Ashton does) and getting the signal from combining the coil signal wire and coil power wire like the factory harness. It looks like I'm going to use the factory style but really I don't think it matters much one way or the other.

Onward and upward!

Also this should have been painfully obvious, but if you do this the right way, you'll have both options available to you for getting an inductive pickup. If you group the power/signal wires and isolate the ground wire, you have both sitting there free to use. :o

Good to hear.

When I'm done I'll double check with a spark plug wire to make sure the timing isn't any different.

done the check yet?

[[/I]Can you run a Cdi box with these coils? I've heard that you cant run cdi boxes with smart coils.

Not yet. I got the car to fire up and run strong after an initial hiccup with having two of the coil signal wires swapped.

However, right now it has a seriously jumpy idle where it finally oscillates itself to death. I need to figure that out, and then I'll run the test.
Honestly, I think my issue might be a bird family that took residence in my exhaust.

I do believe that is correct, but I can't say 100% for sure, or why.

I have the definitive answer to the question of whether or not you can get accurate timing info from the power+signal wire, or from the ground wire on this type of COP setup.

The answer is no, you cannot.

Timing info from the power+signal wire is about 7 degrees retarded from actual at idle speeds. As RPM climbs, the error gets worse and worse so by the time you're around 4k RPM you're off the timing marks entirely on the advanced end.

Timing info from the ground wire is about 10 degrees advanced from actual at idle speeds. As RPM climbs, the error gets worse and worse so by the time you're around 3k RPM you're off the timing marks entirely on the advanced end.


Using the coil to drive through a high voltage spark plug wire to the spark plug gave me accurate readings, and the readings stayed rock solid as RPM climbed to around 5k RPM where I traditionally stop testing.




I have an inkling that if the OEM loop in the 20V/VET/S15 wiring harness is designed to let you time the engine with a timing light, I believe the procedures probably dictate idle RPM only and tell you to set the timing 7 degrees or so retarded from actual. Meaning the FSM probably tells you to set timing by the marks at 10 degrees BTDC but in actually the ECU is locked at 17 degrees BTDC. That's my best guess anyway.

really. i have dont this both ways on my car and they come out exactly the same.