Nathan F

Can someone help me 'read spark plugs'? My little franken-derp miata tried to commit seppuku again. Net result seems to be the 99-00 coilpack crapping its pants again. 2x over 2-3yrs. I ordered the fab9 kit to fix it. 04 engine, 99 miata, no vvt running right now since I need warmer weather to finish wiring the vvtuner.

I had one wet/damp plug, one with a tiny bit of ash, and one with a pretty good amount of ash. The codes were p0300 and p0303. Here's how they looked by the numbers (and as viewed from the front of the car)
#4 - a bunch of ash
#3 - a tiny bit of ash
#2 - a little wet
#1 - seemed normal

Since 2&3 fire from the same pack, I could see those two being borked. I really don't get why #4 would be ashy though, which as far as I know means it is running lean. Is there a correlation between a pad coil for 2&3 resulting in a lean #4 cylinder?

Girz0r

iTrader: (1)

Here you go.

And here is a helpful NGK page

Nathan F

Thanks, bud. I did look through some stuff like that. Just curious if there would be a link from the condition of a bad coil causing the good one to be ashy. From the pictures I guess it sounds like its unrelated.

I just don't want to miss a chance to diagnose something. Preventive maintenance I guess.

Girz0r

iTrader: (1)

I wasn't aware 99-00 coils work on a 04 vvt motor

And if you're burning oil, I don't think the fab9 kit will help all that much.

Nathan F

yeah, you can use 'em. Been 10k miles on that setup. The plug wires should be shaved a bit since the spark plug boots stick up about 1/16th" or so otherwise. The only differences between those engine setups should be spark source (cop vs coil pack) and VVT.

Girz0r

iTrader: (1)

I guess my real question is, why use them on a 04 motor when the NB2 coils are known to be of better quality?

Nathan F

Well, simplicity was the main reason. The articles I read about the NB2 into NB1 swap all seemed to point at just using the 99-00 setup. It doesn't mean it's right though. And, I probably didn't know any better at the time. However, that's why I've since gone to the FAB9 COP setup.