Coil on Plug stutter
 

Hey guys, been lurking around for a while but I've ran into a problem which either me or my mates can figure out.

Before I get flamed, i want everybody to know I've already tried searching for stutter, surge, sputter, etc.. but haven't been able to get the answers I'm after

Basically what I've got is a stock NA6, with a pod filter and a set of extractors and a 2.5" system. I've just made up a Toyota COPs setup using the wiring diagram in the garage section of miata.net. I've noticed better response and bit more pace.

But the problem is when cruising at around 3-4000RPM, the engine would have this problem where as if it felt like a misfire, a single surge where I'd loose a bit of power and then it'd come back on again within a few milliseconds.

It happened about 5-6 times within a hour of first installing the COPs at that certain rev range and then when I wired in the 10,000uF capacitor, its probably done it about 2-3 times within the last week, but thats also because I haven't been driving it much so I can't know for sure.

I'm running a set of NGK Iridium plugs, I'm also sure its not the coils because I tried another set of Toyota coils along with a different COP loom and still the same.

Any ideas of what could be causing it?

bump! does anybody have an ideas?

Might add that it seems to be a ignition issue, like the spark is getting cut as if you were running on the rev limiter

Just 3 posts... Anyway: do you have a sync-loss?

sync loss?

have you taken any logs? I am experiencing a similar issue. Are you going tich or lean during this episode?

I'm running a stock ECU so nope

Errr... Crap.
I hate stock ECU's.
Did you had some kind of dwell adjustment? If not: you are overcharging the coils and they will become superhot and unstable. I have seen overheated COP's causing problems before.

I thought you needed a dwell reducer for the stock ecu???

No dwell adjustment, can that be causing it?

My coils are hot, like unbearable to touch hot.
wierd thing is i know two others running the exact same cop setup with their stock MX5's and stock ecus and have no problems at all..

Yeah, that's going to be a problem.

Do yourself a favor, save the money, and get MS. It will make your life significantly easier.

Megasquirt has been on the cards for a while now, still trying to save up :(

Ive had similar problems in the begining with my setup which uses k series coils. check to make sure the plug well is dry and at the spark plug use a bunch of dielectric grease to help seal in the spark. mine was arcing out in the well and wasnt tightly seated down on the plug. it made all the difference. if its not these details its the dwell or temp