vworley

I've looked and looked, and I'm sure missed, a thread with info on the correct connections for Leading and Trailing coil connections. Also, leading and trailing rotors.
I did find a few threads, but one in particular seemed to contradict itself.

So I'll ask here. Which coil is leading, which is trailing?

And, to confirm, the top plugs are Trailing, bottom are Leading, with Rotor 1 closest to the radiator and Rotor 2 closest to the firewall?

Rx-7Doctor

iTrader: (13)

Trailing coil is the one closest to the battery.

Other questions are yes and yes.

74RX4

iTrader: (10)

Stock position is trailing coil in front, leading towards the rear. Both + coil terminals should have a larger gauge Black/white wire with a rubber cap. Trailing coil - terminal should have normal gauge Yellow/green wire. Leading coil - terminal should have Yellow/blue wire. Your descriptions of top, bottom, front and back are correct.

vworley

Ok. I see the Trailing coil has two normal gauge wires going to it, while the Leading only has one, the yellow/blue. I think I read this is due to the fact that it fires the two plugs at different times.
Since I posted this, I've looked at two other cars. Both of them were improperly configured based on the information provided above, but seemed to run. Glad I asked...

The car is running rough, and gas mileage is very poor. I wonder if one of the coils isn't firing properly.

gsl-se addict

iTrader: (3)

The (+) of each coil should have a BW (black w/ white stripe) or BY (black w/ yellow stripe). The (-) leading is YL (yellow w/ blue). The trailing (-) should be YG (yellow w/ green).

The 2nd wire on trailing is because the tach gets its signal from trailing. If the tach works, then trailing coil is firing. However, leading is most important. If leading is not working, then it will run very poorly and have no power. You can check spark with a timing light. An easy way to check without a timing light is to pull one of the leading plug wires and put a spare spark plug or end of a screwdriver in it and lay it on the inner fender. Crank the car and look for spark.

Running rough could be many things, but I would start with ignition. Check for spark, check timing, inspect/replace plug wires, distributor cap, and distributor rotor. The coils usually do not go bad (it does happen, though).

Let us know what you come up with and we can go from there.

Kent

vworley

alright, I've put new plugs, wires, distributor cap and rotor in. It's still running rough. It seems worst below around 4K rpm, then smooths out somewhat. Is there a way I can check the coils?
I made a quick pass checking all the little vacuum lines, but may just need to replace all of them. They all look pretty good though. Not dry or crumbling. Although, there is a large one up top that looks pretty loose.

At least it's running!

gsl-se addict

iTrader: (3)

Do you have a timing light? It will show you if timing is good, but can also show erratic/missing spark too. At least it can help to tell you if it is an ignition problem or if the problem is somewhere else.

vworley

No I don't have one. I'll see if I can borrow a timing light from someone.