So my car was running great but then yesterday, it ran with no power. Seems like it was running on one rotor. I check today and I don't have spark in just one of the front leading coil. Isn't the leading coil one unit? What should i be checking? I also swapped the wires to confirm the wires are good. Just no spark on the Leading front coil (Top line of the leading coil pack)

 

Yeh it's almost always the coil, they have a habit of failing from all the heat and just being ~25 years old.

You can sometimes see a faint crack in the coil when they have failed but it's very hard to see.

 

There's a test in the shop manual for the coils, it's an easy test and I've found the results to hold water. I would also double-check the plug wires to make sure they are in good shape as well as the coil pack harness.

If it is bad, you can get a good used one for a fair price, get a new one from Mazda (pretty expensive if I remember) or go with an aftermarket ignition system. If your car is someone stock I would probably stick with a stock coil though. They really do a good job and failures, while not unheard of, are not super common.

Dale

 

I was looking at the manual and it just didn't make sense that one side would fail or so I thought. I swapped the wires and the wires aren't the issue. I went ahead and ordered a used one. Thanks!

 

Facing the engine from the driver side, left most coil is rotor 1 trailing, the center coil is both leading plugs, and the right most is for the #2 trailing.
Since the leading runs a wasted spark and fires both leading plugs, and you swapped wires with no change, then the #2 leading plug is internally shorting.

Or you are confused as to which is which.

 

Using an MSD test plug I've found that if you have a nuked plug/broken wire/unplugged wire in the front leading position the rear leading doesn't like to fire. Food for thought.

 

The middle one (leading) only half works. 1 shoots a great spark. The other 1 doesn't fire which I thought was weird since they both come from the same coil.

Are you saying the trailing plugs are more important than the leading? I always thought the trailing was for just cleaning up the rest of the unburnt fuel and you needed the leading to run the motor.

 

The top coil on the leading coil doesn't fire. I believe I have the top one plugged into the front Leading coil. Should I try to reverse them?

 

Since the leading coil is firing at lease 1 spark plug, then somewhere in the other 1/2 of the circuit is a short.
It could be in the plugs, plug wires or coil. If you switch both the wires and plugs, that will give you your answer.
The stock FD leading coil is known for being a weak part.
That is why I switched to a TII leading coil, and fire the trio by a HKS Twin Power.

 

Is the TII a direct switch? or modification necessary?

 

It's a decent amount of modification, definitely not a bolt in.

You're on the right path, get a good used one. It is also possible the coil pack harness is bad. The original harnesses have a ground wire that attaches to one of the coil nuts/studs. The revised version doesn't have that ground wire. THey're about $80ish new from Ray Crowe.

Dale