No go. Misfired only twice over 2 hours. So a little better. But not fixed. Sanded grounds. But still no definitive fix.

 

Passed with flying colors

 

Look at the cluster of grounds under the brake booster, I had to pull the spade connectors out of the clip and clean everything, reassembled and used a stud on the fender by the fuse box so it wasn't sitting where water/oil might get. Was having issues with the tach flipping out as well.

 

Thanks. I'll try that tomorrow. Need to prep the car for the track. Taking a half day off to swap pads, do a general bolt check and probably flush the radiator. I should have enough coolant. Cat also needs to come out.

Its funny I almost want the misfire to get worse so I can actually diagnose it instead of just replacing parts. If it was consistent I could just scope the damn thing.

 

Are the nb and NA ignition switches the same?

 

You did say you wanted the misfire to get worse...

 

I seriously doubt it is the switch. While they do get all gummed up and look like hell, it's has been my experience that they either work or they don't. Mine sometimes clicks with no start, so I figured that was the first place to look.

Jiggling the switch (and even hitting it fairly violently) while running produced no stumble or cutouts. I just couldn't reproduce the stumble while stationary. Mine happens after hitting a bump, so I'm convinced it's a loose electrical connection, but damned if I can find it.

That said, there are write-ups on disassembly (http://www.miata.net/garage/CleaningIgnitionSwitch.html) of the ignition that are very helpful. Doesn't hurt to take it apart and clean all the gunk out then put new contact grease in. Like the shifter, it improves the feel.

 

Swapped switches last night. Problem disappeared for an hour. Swapped back tobky original one. Problem still gone. So still a mystery.

 

One session down. Still no misfire.

 

Bad connection at the switch, fixed by re-seating it?

 

That's my guess.

 

Track day rundown:

Day was epic car was amazing. I had a nice 60mph off that included the shifter falling out. Otherwise the twin disc is magic, turbos are awesome, and I ******* hate air cooled 911s.

 

Shifter fell out???
Air cooled 911s are epic, what is your beef with them

 

Bit of an exaggeration. But there were 3 or 4 of them that wouldn't give point bys all day. I had to pit twice because I was stuck behind them.

Shifter was crazy. I had an off on turn 1 (I'll have video tomorrow) and then I went to shift into first and the shifter had basically come out. The bolts that hold it down were too short and only had a couple threads of engagement. I was able to shove it into 3rd and limp into the pits. So we rigged this up with bolts that were way too long.



Had an 8 second improvement over the day. Not too bad.

 

Holy crap haha.
Lap times?

 

I started at a 2:13 (traffic, morning etc) and did a 2:05 my last session. I think Ed went from 2:10 to 2:01

 

 

That's my kind of track -- minimal concrete, just room for 4x4 action.

I actually had a contact come loose from the ignition switch connector once. Pushed out just a bit, but enough to be intermittent. That was a fun one to find. Contact cleaner/lubricant, a good light and an inspection mirror are your friends.

 

Yeah. I didn't realize that ignition power came directly from the switch.

@patsmx5 was right, something was causing power to not be delivered to the coils.

 

Ok longer track day story now that I have time at a computer.

All week I had been slowly getting the car ready, and the misfire wasn't horrible. It happened so rarely that I was fine driving it to the track. I took a half day friday to finish prepping the car, and left just in time to be shafted by traffic. Misfire started within 5 minutes of driving, and continued to happen every minute or so. Started stressing out, but kept on truckin. Just tried to get to the hotel and work on it.

Got to the hotel, and while everyone else drank beer, I worked on the car. I had basically checked all the ignition power connections in the engine bay and wondered where the 12v for ignition came from. I pulled up some wiring diagrams (thank god for motel wifi) and realized it came from the ignition switch.

I started brainstorming how to jumper and bypass the ignition switch, but all I had was 18 gauge wire. And even I'm not that stupid. So I grabbed one from 's car and plugged it in. Went on a 30 minute drive. No misfires.

Called my roomate in portland, at 11:40 he went out and pulled an ignition switch from the parts car. Hes never worked on a miata, and I had to talk him through it on the phone.

Ed then picked it up at 4:30 the next morning and brought it to the track.

ORP is awesome. Love that track. And the car was great. The twin disc+mr short shifter is heaven. I didn't have to think about shifting, it just happened effortlessly.

Im still a slow driver but this car is a blast on the track. I beat on it all day and no issues (other than going off track and loosing the shifter). Got 35mpg on the trip down there too. Not bad.

ABS swap is great. I didn't worry once about flatspotting tires, and I probably saved a tire. I was working on pushing my braking zones and went a little to hard into one. ABS kicked in and worked great. I'm super happy with the brakes right now and have 0 regrets about doing the ABS swap. I think its great insurance for anyone learning to drive. It shouldn't be used as a crutch, but it can save tires.

Future plans: I need to stop working on this thing for a while. Just picked up a mountain bike for hailey, and some new dirt bike helmets for both of us. I'm tentatively planning some June days, but haven't signed up for anything. I purchased some splitter material and have some lexan, and want some front and rear aero before the next track day. I'm tired of ripping off my gv lip in the dirt/shrubbery.

Picture dump (the white porsche locking up its brakes was the guy that "didn't see" the passing flag for 4 laps):