just a seperate side note... this is problem not your problem, but i ex[perienced some funky readings using a cheapo timming light. Aparently the inducer was picking up the leading spark at the same time as the trailing and i was getting inconsistent readings.. bought a nice craftsman and no more issues...

 

Looks like the T1 and T2 plug wires may be switched

 

That's what I was thinking.

 

Yeah, you should really verify that everything is going where it is supposed to go. You don't want to end up with the trailing/leading switched around. Trace everything from the start and you might find your issue. Good luck...

 

can somebody draw out how the spark plug order is, like how i had done.? On my dizzy cap it reads the L1,L2,T1,T2 and i have the wires coming off of those and going into the plugs like how i have listed..

What i dont get is if leading is set how can trailing be THAT far off??????

 

The way I remember it is :

Leading are the "Lower" plugs
Trailing are the "Top" plugs
Rotor 1 is the rotor closest to the front of the car
Rotor 2 is the second one

T1 T2
L1 L2

So I the image posted looking at the engine from the driver's side is correct. I don't see how T1 and T2 could be switched unless they were done on the dizzy cap, or your dizzy cap is on backwards or something.

Jon

 

What I meant is, check to make sure that:

1. The leading ignitor (front of dizzy) is connected to the leading coil. I mean the small wires, not spark plug like wires.

2. Make sure that the leading coil is hooked up to the leading spot on the dizzy.

3. Make sure that the leading plugs are connected to the leading spots on the dizzy cap.

4. Repeat process for trailing system.

After much searching and tinkering, while trying to solve a strange running issue, I found that my leading ignitor was hooked up to my trailing coil. Needless to say, this caused some issues. I have no idea how it happened, and don't remember ever changing it, but these things happen I guess... I'm actually surprised that it didn't cause more issues than it did.

For the plug wires themselves, it should be pretty easy. Both the cap, and the motor, should be marked. So, just make sure that T1 on the cap goes to T1 on the motor, etc. and you should be all set there.

Good luck man...

 

So, I know this thread is super old, but it recently helped me tremendously, and I felt like my comments could help other readers since the op's problems were never resolved on this thread.

I have an '83 12a limited edition. I've been trying some ignition advance stuff I've learned off of this forum and various sites. Unfortunately, while timing the engine, I noticed my trailing was reading to be more advanced than the leading, just like the op's diagram. Kentetsu's recommendation of checking the ignitor wires to the coils led me to swap the coil-to-distributor leads (i.e. the ignitor-to-coils electrical wiring was "reversed"). Either way, changing the leads led to the desired effect: my leading plugs are finally showing to fire at more advanced timing than the trailing (exact opposite of before). At stock adjustments, my timing marks line up with the timing pin appropriately, though I now have them advanced per my desire.

Bad news (if any) is that it didn't change how my ignition fired (I had already advanced it by ear/sight/feel, despite the bad timing readings), but the good news is that I now see correct timing marks and adjustments.

Hope this helps future readers.