Forgive my ignorance, A/M ignition

NoDOHC · 12-12-2010, 12:55 AM

Wow ReTED, you should make that a sticky. I thought I was a little sparse in my description, but you have put me completely to shame!

Kudos to you!

The only question that I have is:

I thought that the stock coils fired using wasted spark. This is usually configured so that the current must pass through both plugs. It seems strange that a wasted spark system could possibly fire on only one of the plugs (are you sure about the cause of this symptom)? I am using the stock ignition and I only get misfires if I lean the mix up too much. Otherwise the engine purrs as smooth as glass. I think it might be more of an ECU issue.

Pete_89T2 · 12-12-2010, 08:35 AM

Quote:

Originally Posted by NoDOHC

I thought that the stock coils fired using wasted spark. This is usually configured so that the current must pass through both plugs. It seems strange that a wasted spark system could possibly fire on only one of the plugs (are you sure about the cause of this symptom)? I am using the stock ignition and I only get misfires if I lean the mix up too much. Otherwise the engine purrs as smooth as glass. I think it might be more of an ECU issue.

The leadings coils fire wasted spark, the trailings do not. The leading coil is essentially one coil with its output wired in parallel with 2 towers. So for every spark event triggered on the input side of the leading coil, in theory you get a simultaneous spark firing at both leading plugs.

RETed · 12-12-2010, 10:00 AM

It's just a lot of crap floating in my head...
Trying to type everything coherently is the big challenge.

Like Pete_89T2 said, the twin tower leading coil is just like a regular single tower coil except it has two towers...outputs...in parallel.
As long as the coil can discharge it's charge potential, it doesn't matter if it fires out one or both towers.
In an ideal situation, it fires two (identical?) sparks out the twin towers.
In reality, the wastespark system doesn't allow for balance loads across that twin tower leading coil.

One spark is firing in a pressurized, air + fuel combustion chamber - more resistance to firing a spark across the gap.
The other spark is firing in a highly charged, ionized (exhuast) gas, decreasing pressure combustion chamber which is a whole lot easier to fire a spark across the gap due to 1) less pressure and 2) ionized burnt particles of carbon.

It's this imbalance that causes the misfire of the twin tower coil.

-Ted

12-12-2010, 12:55 AM	#1
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	Wow ReTED, you should make that a sticky. I thought I was a little sparse in my description, but you have put me completely to shame! Kudos to you! The only question that I have is: I thought that the stock coils fired using wasted spark. This is usually configured so that the current must pass through both plugs. It seems strange that a wasted spark system could possibly fire on only one of the plugs (are you sure about the cause of this symptom)? I am using the stock ignition and I only get misfires if I lean the mix up too much. Otherwise the engine purrs as smooth as glass. I think it might be more of an ECU issue. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)