So a while ago, my car started running like crap, and I thought I bent some valves. Turned out a coil on my COP system was fried. Here's what the coil looked like.





I swapped out all 4 coils and everything was good. I also completely rewired the setup with heavier gauge wire, to alleviate any issues that may have been caused there. I chalked the issue up to a bad junkyard coil, and called it good. The car has been running great on the COP setup ever since...until now. Fast forward from the last time I had an issue till now (about 1,500 miles later). I've been driving the car to work while the weather is still nice. I'm almost home after a 40 mile drive, and the car starts to cut out a bit. I can tell it's the same feeling I got last time when the coils sh*t out. I make it home fine, and pull the car in the Garage. I immediately pull out my stock coil and plug wire set and swap it in. I hit the key and the car runs perfect.

At this point, I do a visual inspection on the coils. No crazy damage like last time. All the coils look good, but I know one or more of them are garbage. I used up all my spares, so I can't just swap in a new set like I did last time. I derped around on the net trying to find the test specs for the coils and didn't find much. However, I did find a post from a guy who had a ground issue and fried one of his coils. It looks strikingly similar to the first bad coil I had:


Here's the thread ---> click
Quoting dude from internet:
The engine ground decided to take itself off the engine. After about 30 min of no ground, a coil exploded and my throttle cable is slightly welded. Dumb mistake /ubbthreads/images/graemlins/mad.gif. At least I figured out that the coils I'm using are 2.7L Dodge Intrepid coils and they're $50 a pop! /ubbthreads/images/graemlins/rofl.gif



After reading that thread, it makes me wonder if the coils aren't grounded well?

Here are my questions:
-What are the test specs for the intrepid coils, and how do you test them?
-Can you add a secondary ground or something to the COP system to supplement the ground already provided through the ignition harness?
-Anyone ever have any issues with COP coils shitting out on a consistent basis?
-Should I add more engine grounds. Right now I have a custom ground kit I built consisting of about four 8ga wires running from a body ground to various places on the trans and block.

I would have already swapped the stock ignition system back in if I had a good mounting point for the coil pack that actually looked clean. I'd like to continue using the COP setup if at all possible, but not if I keep having issues with reliability. Can you guys help a brotha out? Thanks in advance.

on the side of the coil with the numbers and letters mine are different. top left is : 04609 bottom left is : 088ah bottom right is : 0525. im not sure if its a different coil as i bought it already built, but all 4 are matching. maybe the ones you have are from a different car.

How long have you been running that particular cop setup?

Upon closer visual inspection, I found this. Now, I'm wondering when/how this happened? It clearly got hot...



I tested all the coils I have. They all measure 0.6 - 0.8 ohms (testing between the 2 connector terminals). Even the bad coil measured ~0.6, so I'm going to make the assumption that testing the coil's resistance isn't a very good way to tell a good coil from a bad one.



Quoting Vader:
How long have you been running that particular cop setup?


This system has about 2,000+ miles on it. I also used it on 1813 for a while, so some more can be added there.

Sorry to say the finding of more damage awaits you. while running a missing ground will slowly overheat things but during cranking it'll take any route it can & overheat melt any circuit that cant take the load.

I don't believe testing a coil with an ohm meter will give you the results that you are looking for. The coil winding's are far to small and spaced to closely together for your ohm meter to push a voltage through. If you had access to an megger to actually push a variable voltage through the coil, you could possibly get a result.

I would say at this point figure out where the coil harness is grounded and check/clean the ground. Replace the pigtail pictured and associated coil. If your still in the dog house after that i would be looking in to building a new cop harness. Are all the connections on your harness soldered or did you use asshole connectors?

I've had a cop set up on #224 for about 4k with out any problems and we're both using the same style coils.

Ditch the COP setup altogether. People have gone 9's, possibly faster on the stock coils.

The COP systems do change the way the spark current flows to ground, compared to the stock dual output coils. So a good ground to the head is more important than our OEM configuration. But that probably isn't what you are seeing here.

It looks more like long dwell(or excess energy in) is leading to severe overheating. A short in the wiring would do it too. I'd tell you about all the coils that I melted in a similar fashion while testing ignitions, but then you'd want proof. Maybe the problem is being made worse by underhood heat. Is your alternator output good?

Just out of curiousity, are you using the COP on an otherwise stock ignition? If so, it is generally a performance downgrade from the OE coils, comparing new to new.

Quoting SouthCaliVR4:
Sorry to say the finding of more damage awaits you. while running a missing ground will slowly overheat things but during cranking it'll take any route it can & overheat melt any circuit that cant take the load.


There's no missing ground, so I'm not sure what you are referring to. I actually have a ground system that's more robust than the factory system. In addition to the factory grounds, I have added my own in various places on the car.


Quoting bradrs:
The COP systems do change the way the spark current flows to ground, compared to the stock dual output coils. So a good ground to the head is more important than our OEM configuration. But that probably isn't what you are seeing here.

It looks more like long dwell(or excess energy in) is leading to severe overheating. A short in the wiring would do it too. I'd tell you about all the coils that I melted in a similar fashion while testing ignitions, but then you'd want proof. Maybe the problem is being made worse by underhood heat. Is your alternator output good?

Just out of curiousity, are you using the COP on an otherwise stock ignition? If so, it is generally a performance downgrade from the OE coils, comparing new to new.



Thanks for the info. My alternator is brand new. Typical output voltage is around 14.2v according to ECMlink.

I am running the COP system on a stock ignition system (no CDI box). The main reason for this is because of my Magnus SMIM. There's not a great place to mount the coil pack where it still looks clean...at least not as clean as the COP system. In addition, the area I want to custom mount the stock coil requires extra long spark leads, which need to be purchased individually. A typical wire set wont work for a remotely mounted coil pack. In short, the COP was just an easier option for me at the time. At this point, it is proving to be more of a pain though, and I'm looking into other options for an ignition setup.

So, if keeping the COP is my goal, what would you suggest, Bradrs?

Just FYI I'm running a magnus SMIM, factory coil, factory wires and all it took was the ~40 dollar JMF coil bracket, fits great.

That JMF bracket won't work on cars that still use AC.

Me and Andre fabbed me a bracket that puts my stock coil under my SMIM, but I had to custom make wires from an MSD kit. The stock leads were too short.

I'd like to go COP to simplify things and clean up the bay as well, but too many horror stories like this keeps me away.

Quoting GSTwithPSI:
I am running the COP system on a stock ignition system (no CDI box). The main reason for this is because of my Magnus SMIM. There's not a great place to mount the coil pack where it still looks clean...at least not as clean as the COP system. In addition, the area I want to custom mount the stock coil requires extra long spark leads, which need to be purchased individually. A typical wire set wont work for a remotely mounted coil pack. In short, the COP was just an easier option for me at the time. At this point, it is proving to be more of a pain though, and I'm looking into other options for an ignition setup.

So, if keeping the COP is my goal, what would you suggest, Bradrs?



The problem with COP is that the dwell from the ECU doesn't work optimally with the dwell for the coils. A CDI like the ARC-2 is a quick solution. A really nice guy even went out of the way to make them plug n play.

But to be honest, I'd want to track down why you are burning up coils before changing the coils out. It could be something else causing the issue. And if so, changing the ignition may not solve the problem, you might just wind up with a burnt out CDI box too.

Have you double checked your wiring to make sure the coils are in series as they should be. I have occasionally seen people wire them in parallel. I'm surprised your PTU wasn't fried also. Does the PTU still seem to work? It that makes me wonder if there wasn't a short that was the cause of the coil being cooked, because a PTU can only supply so much current on these cars.

I wire the system up according to this video: click
And this thread (same thing): click

I have enough stuff to build second COP plate, so I decided to completely redo the whole system. I got a new set of coils (all 4) and rewired the whole thing. I didn't reuse anything from the other COP system I was having issues with. I bolted the new plate in and the car fired right up. I also added a couple ground wires going directly to the head, which terminate at a clean body point. I'm going to keep an eye on the system and check the connectors a few times a week.

I screwed with trying to find a mounting point for a custom bracket for the stock coils, but it was going to be a huge pain in the ass. Especially with the intake manifold still in the car, it's almost impossible to get positioned to mock up a bracket.

I thought about something like this:


But I don't love how it looks, and it also requires custom spark leads which I don't have just laying around. I'm going to give the new COP another run and see how it performs. Thanks very much to everyone who helped out in this thread. I appreciate it.

That install looks like it is wired correctly, but (and I don't mean offense to the guy who wrote it) that looks super ugly to have that many solder joints all over this one little subharness. I understand he did it because he was working with a bunch of precut pigtails, so he did what he had to connect them.

One thing to keep in mind with your ground points on your head. I can't tell if your valve cover is painted or anodized. But anodized aluminum doesn't make for a very good ground path either. On the stock coils, the spark current basically recirculates across the head and doesn't go to the system ground. But with the COP, you are completely changing the spark ground path, so that it has to go through the system ground.

My valve cover is just painted. I'll post up some pictures of the grounds I added to the head in a bit. So far, the car seems to be running fine, but that's not to say it doesn't sh*t out in the near future.

Could you explain a bit about how the spark ground path is changed? I'm trying to comprehend how I could improve the ground side of this circuit (the harness). Or, would that even help?

Since I have you here answering questions, could you take a quick look at this thread when you have time? click

^The Denso coils have a third wire exclusively for a ground. I would love to fab up a system like this and try it out on my car, but I'm not familiar with all the technical specifics of these particular coils (and honestly, I'm not even exactly sure what coils they are...Civic coils?). I gather from the few hints you've alluded to, you have quite a bit of experience developing aftermarket ignition systems (CDI, and more specifically the ARC-II) for the 4G63 platform, and would probably be the best guy to ask about such a venture. Hell, maybe you've already done it and can tell me not to waste my time. The extent of my insight is pretty much summed up by saying it worked on some random dude's 4G63, so why not give it a try? Thanks again for your help, Bradrs.

Edit 1: Found the coils ---> Denso FTW?

Edit 2: Drew this up real quick. Can someone check my work?


Here's the diagram/thread I stole this from: click

On electrical circuits, current flows in loops. It will flow from 12V to ground through a load, but there is also a matching current going from ground to 12V through your voltage supply(or battery). This is a basic electrical theory. So when you picture the spark current, you need to draw the loop. I really should make drawings for these sometime to post them.

The dual ouput coils are very simple. Each end of the secondary is tied to one of the plug outputs. The voltage is generated in the coil secondary. This causes current to go out one plug wire, to the plug. It jumps the gap, goes to the head. Then it goes to the other plug, back through the gap, up the plug wire, and into the coil. That is your loop. And it doesn't really use vehicle grounds for anything on the coil secondary.

Now if you have a single output coil, it is wired differently internally. One end of the secondary goes to the plug, and the other end goes either to a ground post, or it is tied back to the 12V line.

Lets look at the case where it is tied to the ground first. When the coil fires, the current goes down the plug wire, to the plug, jumps the gap, goes to the head. From there, it has to get to that ground post. On the coils you showed a link to, it is a pretty straightforward ground path. But if it is tied into the vehicle ground elsewhere, the spark current has to get to that location through the vehicle grounds.

If the coil secondary is designed so that it is tied to 12V, then the path is even longer. It goes through the coil, plug wire, gap, to the head. Then it goes to your system ground, through your charging system/battery to the 12V/feed wire that feeds the coils.

If you have paint, anodizing, or any other coating that blocks these current paths, you can run into issues.

The real problem with using other coils, is getting the dwell right. That is why the CDI simplifies that. But if you are just trying to use the coil, then you want to pick one that is similar enough to the DSM so that it charges well enough, in the same time as the DSM. BUT, you don't want to charge much more than that, because the stock DSM ignitor limits you to about 6-7A. You can use workarounds on this, but most are complicated, or not cheap. And I don't think that anyone right now is adjusting dwell times with a factory based DSM ECM.

That was an Evo in that 25 page link right? I didn't read it all. But if it is an Evo, then it will wire differently from a DSM, since their PTU is basically built in to the coils. And I know some Evo guys have figured out how to adjust their dwell in their ECU. Aside from that, I don't know enough on the coils to say if it is a great idea or not. But most of these swaps have their issues.

I tried a few years back to use the newer Mitsu coils to make a COP system (for the GVR4) that would eliminate the power transistor also. But I am not enough of an electrical expert to figure out how to use the stock ECU to power them correctly. I still hope to get back to that eventually.

You need hayabusa pencil coils. Quit being cheap. Or these high output coils (smart/ dumb) >> click

Forget about the aem pencil coils in the link, those are only good to about 15 psi.

The last time I looked at the EyeAbuser pencil coils, they were a horrible match for the stock PTU.

The other coil is a strong coil, but it also wants a lot of current, and I'd be concerned about dwell time being too long for these, over time. I suspect they'd run great for a while if you have your wiring done right though.

Quoting G:
You need hayabusa pencil coils. Quit being cheap. Or these high output coils (smart/ dumb) >> click

Forget about the aem pencil coils in the link, those are only good to about 15 psi.



Hayabusa pencil coils, eh? Could you draw up a wiring diagram and show me how to wire them in?

I've noticed you throwing around the term newb an awful lot lately. What's ironic, is in just the few years I've been here, I've never once read one of your posts and said to myself, "Damn, this guy knows his sh*t". Quite the contrary, actually. I read most of the stuff you post and just lol at the amount of incorrect or misinformation.

Maybe you should stick to crying about rust, peddling overpriced parts and posting when parts are NLA /ubbthreads/images/graemlins/dunno.gif

Quoting bradrs:
The last time I looked at the EyeAbuser pencil coils, they were a horrible match for the stock PTU.

The other coil is a strong coil, but it also wants a lot of current, and I'd be concerned about dwell time being too long for these, over time. I suspect they'd run great for a while if you have your wiring done right though.



When you say wired right, would that differ from the diagram I drew above? I basically just adapted the Denso coil in place of how an intrepid coil would be wired into the system. Thanks for the help.