Does anyone know the specs on the stock FC leading coil? Specifically resistance and voltage.

 

I read the FSM about that this week when I was thinking that T2 firing off the marks was my problem. It appears you need a special ignitor test tool to do any testing with the coils. Be careful. Coil's pack quiet a punch. Ask me how I know.

 

I'm not going to be testing it. I've zapped myself with a MSD Blaster2 and ir didn't feel good. I wanted numbers in order to compare to aftermarket coils in a custom application.

 

well the resistance should be less then 1 ohm, I dont know about the voltage though.
I dont even think you can measure the voltage on them, unless you have an expensive measurement tool for voltage that can go up to 50k volts
The 0nly voltage testing you can do on the coil is from the BLK/YEL wire terminals, and thats for seeing if there is 12 volts there.

 

on each coil, you'll measure the resistance between the primary terminals(where the spark plug wires slide in). the resistance should be 0.2-1 ohm

 

What exactly are you trying to do? Don't upgrade your ignition system unless you've got spark blowout. You won't get spark blowout until you are making over 300whp at least, and some people have made way over that with completely unmodified stock ignition.

 

It's actually not as crazy as it sounds to measure coil output voltage. Any good electronics store will have a high voltage probe in stock that connects to a regular multimeter. It looks like a large wand with a LOT of insulation and a probe tip on the engine. Inside is a resistor network that divides down the voltage many times so you can display it on a regular voltmeter. They are designed primarily for the TV repair industry.

Though honestly, measuring the coil output voltage is not important. As long as it fires the plug, it's fine.

Also be careful when testing the coil input voltage with your meter. When the coil fires it kicks back several thousand volts. You can fry cheap meters and give yourself a nasty surprise.

 

So does anyone know the primary resistance or secondary resistance? I think my coil might be bad because it's getting very hot under normal driving conditions.

 

Well all the FSM says is that it should be below 1Ohm, but if it's too low it could be bad too. Huummmmmm Well see.

 

The FSM indicates you are supposed to check between the input terminals...is that right?

 

yes. primary voltage should be checked from the + and - on the coil and it should be below 1 ohm. now the reason I'm bumping this is because noone ever posted if they know what the secondary voltage is supposed to be. on all other coils all you do is measure the load from the coil output to the - terminal. I'm not getting any load at all. does anyone know why or what it should be? Primary is at .5 ohm, but I cant figure out any way to read secondary resistance or what it should be. FSM says nothing about the secondary resistance. (which is really dumb for them to leave out) And yes i'm getting spark blowout.

 

I have never seen what it should be on a RX-7. I MIGHT go look at a spare coil in the shed later today or tomorrow. Maybe compare a hot one to a cold one. It's a bit of a bother to go out to a working car and mess around with it.

 

I tried that on a spare LEAD coil and there is no reading at all. Not even a milli ohm. So that test isn't valid for RX I suppose. There's no reason for me to believe the coil I looked at is bad. I've never ever had a coil failure...ever. I'm talking about the secondary coil resistance test in the second depiction in my jpg in the above post.

In the first test above I get 0.3 ohms. But heck, my crummy meter leads touched together give 0.1 ohms, so I suppose the real reading is 0.2 ohms for that.