Attention Joe---Time for a Mea Culpa

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cammerfe

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Several years ago, I decided it was time to replace the COPs. I was doing a general mild upgrade of marginal components and there was beginning to be a groundswell of coil complaints.

I went through a period of study and finally decided that aftermarket---Accel---coils would best do the job. I bought them, installed new plugs and the coils and everything has been OK ever since. (I'd decided that the alterations in the mounting and the necessity for leaving the outside oblong rectangular covers off was of no consequence.)

I've added about 50K miles since that time and recently decided it was time for another set of plugs. But when I did a bit of googling to be sure I was 'up-to-speed' I found comments on line that suggest that it probably isn't best to do a simple straight substitution.

I have found comments that suggest that the polarity of the Mustang COPs I've been using are opposite of the ones the factory used on the LS. This means, as I understand it, that the wiring harness on the car needs to have the wires in the plastic connectors removed and reversed.

Coils will work OK with polarity reversed, but the efficiency is significantly less. In addition, I'm told that the reversed situation is not the very best for the ECU.

If there is someone who can comment on the reversed polarity of the LS as opposed to the early 2000-era Mustang GT---perhaps with reference to FoMoCo wiring diagrams---it would be of significant help.

And if, in truth, the wires need to be switched in the plastic connectors, I'll pledge to do a 'How-To' so that others can make improvements as well.

KS
 
I had the accel coils in my car wired up stock for about 30k, it always took a long time to crank over. Once I switched the polarity of the wires it cranked right over on startup like a new car and I've kept them that way ever since. Also, I used to go through a coil every 4 months or so it seemed, it didn't bother me because they were 40 bucks and could be picked up at autozone, but since I've switched I haven't had another fail. The power delivery seems smoother as well. I can't give you exact numbers, just personal experience. I don't see how switching the wires inside the sockets would do anything to the ECU. According to the first thread, you can actually do damage to the ECU by leaving the polarity incorrect. All you're doing is ensuring the correct polarity going out reaches where it was meant on the coil. If you look on the accel coil you can actually see the + mark of where the positive current is to be input. I have had nothing but improvements since switching polarity and it took all of 20 minutes. There's a pretty in-depth write up in my signature.
 
This is a plan of mine soon as well as some other small projects so this is great info to know before hand. It would be nice to know if they where making any bit of difference maybe I can get that aem dyno that goes on the tranny yoke
 
MMAFIGHTER121 said:
I had the accel coils in my car wired up stock for about 30k, it always took a long time to crank over. Once I switched the polarity of the wires it cranked right over on startup like a new car and I've kept them that way ever since. Also, I used to go through a coil every 4 months or so it seemed, it didn't bother me because they were 40 bucks and could be picked up at autozone, but since I've switched I haven't had another fail. The power delivery seems smoother as well. I can't give you exact numbers, just personal experience. I don't see how switching the wires inside the sockets would do anything to the ECU. According to the first thread, you can actually do damage to the ECU by leaving the polarity incorrect. All you're doing is ensuring the correct polarity going out reaches where it was meant on the coil. If you look on the accel coil you can actually see the + mark of where the positive current is to be input. I have had nothing but improvements since switching polarity and it took all of 20 minutes. There's a pretty in-depth write up in my signature.
Click to expand...

+1. I have been running the Accels for a year or so now with the polarity switched and no probs.
 
If I understand correctly, the problem with the ECU comes from the fact that the factory arrangement with the LS has the switch being in the ground side. This, from my understanding, alters the load the ECU sees. In any case, this may all be a tempest in a teapot, but I'd very much like some input from a knowledgeable person who has access to factory wiring diagrams and the ability to understand what he's looking at. And a big thanks to all!!

KS
 
cammerfe said:
If I understand correctly, the problem with the ECU comes from the fact that the factory arrangement with the LS has the switch being in the ground side. This, from my understanding, alters the load the ECU sees. In any case, this may all be a tempest in a teapot, but I'd very much like some input from a knowledgeable person who has access to factory wiring diagrams and the ability to understand what he's looking at. And a big thanks to all!!

KS
Click to expand...

I don't think that this is correct [I think that all Ford's have the switch on the ground side], but I don't have enough info to be certain.

You want all coils on all engines to be negative polarity on the high voltage side. This is because electrons flow from negative to positive. Electrons prefer to exit from a sharp point headed for a flat plain, so you want the center electrode of the spark plug to be negative.

All (single coil or coil on plug) Ford ignition systems that I know of switch the negative of the coil and power the positive side continuously. (This is from the 60's on, don't know about before that.) The main reason for this is that low side drivers are much simpler and less expensive than high side drivers. Also, the old point type systems worked the same way (on negative ground cars).

It seems to be accepted knowledge that some Ford coils have the positive of the primary on the left side of the connector, and others have it on the right. I really can't think of any good reason for the two pins to be swapped on some. I suspect that it was a mistake that someone made way back when and they are just stuck with it now.

Anyway, I can look up how the LS is wired tonight. My memory is that it is positive with switched ground.
 
joegr said:
I don't think that this is correct [I think that all Ford's have the switch on the ground side], but I don't have enough info to be certain.

You want all coils on all engines to be negative polarity on the high voltage side. This is because electrons flow from negative to positive. Electrons prefer to exit from a sharp point headed for a flat plain, so you want the center electrode of the spark plug to be negative.

All (single coil or coil on plug) Ford ignition systems that I know of switch the negative of the coil and power the positive side continuously. (This is from the 60's on, don't know about before that.) The main reason for this is that low side drivers are much simpler and less expensive than high side drivers. Also, the old point type systems worked the same way (on negative ground cars).

It seems to be accepted knowledge that some Ford coils have the positive of the primary on the left side of the connector, and others have it on the right. I really can't think of any good reason for the two pins to be swapped on some. I suspect that it was a mistake that someone made way back when and they are just stuck with it now.

Anyway, I can look up how the LS is wired tonight. My memory is that it is positive with switched ground.
Click to expand...

Yes, please. And is the LS opposite to the early-mid 2000s Mustang in their locations in the plastic connector, since this is the catalog use for the Accel coils that have become so usually used?
Thanx!!!

KS
 
I saved some pics of diagrams from alldata, lets see if they will attach,
first 2 will be wiring diagram coils and connector view LS,
second set will be 2005 Mustang 4.6 wiring diagram and connector view

ls coil digram.jpg


ls coil plug.jpg
 
Okay, that shows both of them being switched ground setups, but the polarity at the coil connectors is opposite.
 
A very fervent thanks to all for the help in answering this question. Backwards can't be good. Radio Shack sells a little dingus that simplifies the removal of the terminated wires from the plastic connector so I'll be doing the switch very soon. I'll take pictures.

KS
 
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