99 Miata. Just need two things confirmed real quick.
 

Hi, I've been doing a lot of reading as I'm installing a MSPNP2 with wideband on my 99 Miata this weekend. I feel I'm in a good spot in terms of what I've researched, I just have two things I'd like some more clarification on.

1. I'll be using the Innovative LC-2 Wideband/controller. From what I've read it seems I can splice it into the factory 02 harness which I'd rather do just for simplicity. It looks like I need to run a 12v to the controller, ground it where the ECU grounds and then run the output signal to the factory harness and then just cut the other wires on the factory harness. Is this right? It makes sense to me but there seems to be a lot of noise surrounding this from what's read so I just wanted to get a final answer.

2. I will be tuning with a wideband. The unit comes pre installed with a start-up map. it seems that I can use Tuner Studio (full version), with the wideband to auto tune the unit. Fine tuning will be needed obviously, but should that get me close enough for a safe tune until I can get it tuned properly? It's currently N/A, with a turbo going on at the end of summer, but not until I can at least get the N/A tune dialed in first. This is not my daily driver so it does not need to have a perfect tune this weekend but I'd like to get it in the ballpark.

Thank you! I have a lot of experience with working on cars but this is my first Megasquirt adventure so I want to get all my ducks in a row before I dive into it.

1. What you don't want to do is tie into factory "sensor ground", at least not with the wideband heater I have. We did a Spartan in our 99 Champcar build and I did it the same way my NA is wired up, it works great in both that and my NA. (My NA I add a ground wire to back of head b/c it doesn't have the updated 99 NB wiring as stated below)

• We use the Front o2 sensor port, near the cam gears. Your ECU might have a jumper to select front or rear o2 harness, just figure out what signal wire is what. (I don't know if all NA have dual o2, ours is a MA/CA car and the rear o2 seems like an afterthought factory addition)
  • Blue = Front harness wire o2 power. Use this for L2 power. (PIN 3c on 26pin ECU connector)
  • or
  • Red = Rear harness wire o2 power. (PIN 4j on 26pin ECU connector)
• Don't use the red/black wire if it is in the harness, that is sensor ground and will likely mess up your 5v sensors when the wideband heater cycles.
• 99s have a dedicated ground wire for both front and rear o2 sensors. It is a dedicated ground for the factory oxygen sensor heater, separate from the factory oxygen sensor ground. Many widebands share grounds internally which is why you don't want to use sensor ground wire on your car.
  • VIO/YEL = FRONT o2 heater ground, dedicated. Use this for your L2 ground. (PIN 1U on 22pin ECU connector)
  • or
  • RED/YEL = REAR o2 heater ground, dedicated. (PIN 4v on 26pin ECU connector)

2. Good startup strategy. I did the same, I had a MS2, did an engine rebuild, stayed NA to break in and then added boost. You are on the right track, good luck.

I appreciate the reply, thank you very much!