HELP WEIRD THINGS HAPPENING WHEN STARTING
 

Alright so let's me start from the beginning. I just replaced my computer with another MSPNP2 and also replaced injectors at the same time. So I went to the Dyno and went smooth like normal. Then we shut the car off like normal and when we went to turn it back on it just cranked and cranked. So we checked sparkplug wires. We unplugged the wire and it clicked when unplugged(indicating electrical current). This is where it gets weird, only after I unplugged and plugged back in the spark plug wire did it fire up. It ran just fine and no problems so we continued on. Weeks later I was filling up gas and when I got back in it just cranked just like it had before. It would sound like it tried to fire for a sec and then would crank and no start. Tailpipe smelled like fuel and when I towed it home I check the injectors with noid light. Put the light on cylinder 3 and car fired up on of course less than 4 cylinders. So plugged back in the injector wire and still ran on three. Waited for next morning and sounded great and was on all four. I believe this has nothing to do with the CAS because it was getting fuel and the CAS would not explain why it ran on 3 cylinders. Also some side information, after the tune the Miata has cranked sounded like it was gonna fire then cranked again then fired. I can not recreate the issue.(also just bought some coil packs I am gonna put in).

Intermittent, keep this thread going, loose wire ? ground? Or worse , wire which looks ok failing inside ? When it runs fine , for weeks…. Ugh. Probably why you don’t have more input yet. Once, it begins happening more frequently you will find it, hopefully before you hate the car. Preventative maintenance, check a suspected circuit completely , it might mean replacing connectors. I’m guessing, others may know common wiring spots that get weak with age, or because they are moved for maintenance more often. Throwing coils at it might not hurt, perhaps something opens inside on certain conditions but …. Good luck, keep us informed.

I mean that makes sense but only if I was having problems while driving. We have rough roads here in Vegas and I can't see how it would only be a starting problem if it was a wire. If a loose wire was a problem I would expect driving problems too but I am not having any. Now I can't say if what I am about to say is 100% true or maybe my mind made it up. But when unplugged the sparkplug wire that time at the gas station it seemed as though it was delayed and then started to click(spark). Maybe it didn't start because it had week coils and then since it cranked so many times the 650cc injectors fouled out the plugs which is why it ran on 3 and then 4 after waiting but I really am not sure.

Do you drive the car every week? These are two didn’t start events. Both times were spark it seems. Did the coils help?

So the could should be in today and I drive this thing every day. But me and you are in the same page, seems like a intermittent spark issue and the plug wires are some what new and the best ones I could get.

Alright I have some very helpful information. So put the new coil packs in today and before I took them out the car ran fine. Took the old ones out and replaced them and the car cranked. So I hooked up the noid light just like last time and did the exact same thing. Ran on 3 but after I plugged the noid light back in this time I ran it for a sec and car sounded to be back on all four. Must be fuel and the only thing changed about the fuel system since it's had starting issues was I wired up the injectors and replaced the injectors

One bad injector dumping too much fuel ?

I would say no, afrs are fine no sign of to much fuel