Noob. MS2 in a '94 blowing coils at idle. Lots of them.
 

Ok, so.... I bought a MS2 last year and sat on it for a while. Finally got around to installing it a couple weeks ago with Ari's (99MX5) help. Don't worry, I'm sure he'll chime in to straighten up any MS lingo that I screw up.

Setup was fairly straightforward, he ended up needing to solder in a WB lead to the DB15 and VREF signal?

Car idled almost immediately, set base timing, everything looked good and sounded better, however, after 2 1/2 - 3 minutes of idling, it blew a coil. Ari had spares, tossed one in and all was good again. Until it blew that one too... Went through 3 stock coils (it blew the same one every time, pretty sure it was 2/4) before I bit the bullet and ordered COP supplies.

Ari worked his magic on the COP and we had them in the car and running in about an hour or so. Everything seemed right until we felt the COPs, they were heating up pretty bad. He started his car for comparison and my COPs were an easy 20* hotter.

Did a lot of googling over the course of 2 weeks and neither of us found anything concrete. I know he tried to invert spark settings and ran through different coil settings on the MS but we're stuck.

Any insight for an idiot?

what MS2 do you have? DIYPNP? what exact hardware?

https://www.miataturbo.net/attachmen...ine=1373999846

https://www.miataturbo.net/attachmen...ine=1373999846

okay, a DIYPNP, so a microsquirt module.

Spark output should be set to inverted and should not have been touched/changed. there's nothing special about the settings that should be touched, just reducing the dwell number a bit to 1.9-2.1ms.

Tried spark output both ways, blew coils at stock values, still heating them up pretty nicely after un-inverting them.

Not sure about dwell settings and weather they were adjusted.

if the dwell wasn't reduced, i could see them overheating and failing. the stock value is 5.0ms, these needs to be more than half that. So you could be overcharging them.

Assuming the dwell settings were untouched, would your statement apply to both stock coils and the Toyota COPs?

most stock maps have the dwell set to 5.0ms, the toyota cops should be set to 1.9-2.1ms, so...

I've set my COPs to 2.5ms @ 12VDC (3.5ms cranking) per your thread Brain. That still OK? They seem to be running fine.

Thanks for the responses. Brain, here are the engine specs:
-NA block
-NB head and intake manifold

I used the DIYAutotune base tune for a 94 miata to start from. That tune has inverted spark settings. The tune originally on the ECU was set to normal. The only mod I see on the ECU is that it has the sequential injection board and it appears to be working fine.

I set the spark dwell from 3.0 to 2.0 and the max spark dwell from 1.5 to 0.7
Attached is the latest .msq file

Thanks!

Thanks for the help Brain! That did the trick, Stock's car is happily squirted with a COP setup! :)