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

Yah stupid me. There's a capacitor there. Duh.

Jeeze Ben, now your quoting yourself and answering your own questions. hahahaha

No, that would not be a good place to check timing.

Until it is otherwise explained to me, I don't think you can get proper ignition timing information without running a spark plug wire from the coil to the plug and pulling timing from that.

There may be another way to get the correct timing info from one of the three coil wires, but I don't see how. The signal wire gets voltage milliseconds before the ignition event so it is not good IMO. The power and ground wires also get voltage milliseconds before the ignition event so they are not good for timing info IMO. The engine will have turned anywhere from 10-45 degrees between when the dwell time starts and when the spark plug fires. The only place you can reliably know when the plug fires is after the coil IMO.

Normaly on COP engines you just hook your timing light up to the coils negative wire on the #1 coil. The timing light works off of the pulses, The pulse isnt going to occur until that volage is released to fire the coil. The coil always has a constant 12v feed. When the coil grounds you lose that 12v on the negative side of the coil because its being used to power the coil. It wont see another 12V there until the coil ground is released which is the moment the coil fires. Its that pulse that the timing light picks up.

Trust me, we had to do this on my buddies F20c in the AE86 when we were checking ignition timing.

I believe the pulse would still show up on the positive wire as well but like i said the negative side wire would be your best and most accurate wire to use.

I wish my inductor knowledge were a bit better...
I'll take your word for it Ashton.

You know enough about the magnetics that a charged wire makes when it has current flowing through it. Thats what your timing light picks up is the change between current and no current. All i know is it works. I didnt think the timing lights would pick it up either but they do. As the field generated in the 12v wire is roughly 100 times weaker. but it does.

Yah... I just wish I knew more about how and where and when current flows at the beginning of charging an inductor, during, and near the end where the magnetic field collapses.
Dan knows all that stuff. If I knew it I wouldn't have to guess about where a timing event might be good to measure.

I learned a lot of my electrical knowledge when i attended UTI. Before that i kinda knew the basics but i also pick up on stuff really really fast. So not only did i Ace the basic automotive electrical and Advanced electrical systems and diagnostics i ended up with the highest grade in my class in the Advanced and got student of the course. Those were the two classes i thought were gonna be hard because i didnt know much about it going in. But yeah. After that i didnt end up wasting my money staying in for the rest of the classes. It just wasnt worth it to me.

But i will give it that, they UTI in houston has excellent electronics and electrical professors. Definetly learned a lot. I learned the rest just doing it and learning.

Someone should make a How To when all info is gathered. :P

What are the pro's and con's of COP, anyways?

There is a couple threads on this topic about COP's Im sure Ben will be more than happy to post them up.

Some quick off pro's when done right

Better spark energy due to a longer dwell time (due to one coil per cylinder instead of one coil for 4 cylinders) and more direct spark instead of wires
More control over timing
Much cleaner look

On the smaller motorcycle coils which Ben has found out, under boost applications you cant run very much boost or get timing where it needs to be without having ignition issues because the spark from the small coils is actually weaker if using the vehicles 12v power supply to fire them. The motorcycle coils are normally ran with a CDI box to increase coil voltage from 12v to around 450+v depending on system. This in turn creates a much stronger spark.

The automotive COP's are a bit larger so they should be fine as they were designed to be ran with 12v. They can be very powerful with a CDI box as well but were not originally designed for that type of volatage as were the motorcycle coils.

Cons:
You have to use a standalone to run them
Depending on which route you go, you might need a CDI box
You need to be good with wiring to have it set up properly and work as it should without messing something very expensive up.

Other than that, there are not many disadvantages to it.