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Help with building your Speeduino, installing it, getting it to run etc.
By tx_haggis
Writing up my experience in case it helps others. If anyone has feedback, that's great too!

Car: NA Miata (1990)
Engine: NB2 (BP-VE aka BP-Z3)
Speeduino: NA6 PNP
Firmware: 202012

After initially getting the engine running on a modified NB8 base tune, I found that I had hot start sync issues: the Speeduino would not recognize any crank signal, resulting in the engine cranking but nothing happening (in TunerStudio, the "Cranking" indicator would not turn green).

I fixed this by changing the primary & secondary trigger edges to RISING (base tune uses FALLING). This gave consistent cold & hot starts.

I then set timing:
  • In TS set "Fixed/Locked" timing to 10 degrees
  • Use a timing light & adjust "Trigger Angle" until the timing light showed 10 degrees on the pulley indicator.
I ended up with a TS trigger angle of 5° (and then turned off "Fixed/Locked" timing)

Then I re-read (for about the 4th time!) the setup instructions for 99-05 Miata. Which recommend a zero trigger angle and the new ignition mode. Reading the code, the new ignition mode *only* runs with zero trigger angle. So I followed the recommendation (and reset trigger edges to FALLING).

The engine started OK when cold, ran smoothly when stationary. However, it had difficulty revving under load & a test drive required a lot of throttle finesse. After parking, I could *not* restart the engine.

The above happened incrementally, over a couple of weeks during which time I'd also attempted to modify the Speeduino. We then tried:
  • Reset trigger edges to RISING.
  • Checked sensor voltage and continuity to the Speeduino.
  • Checked trigger wheel clearance, orientation
  • Swapped in known good crank & cam sensors
Nothing helped.

With hardware checking out, I decided to ignore the setup instructions and reverted to using FALLING trigger edges, the old ignition mode & 5° trigger angle. Worked great!

Disappointed the new ignition mode didn't work out, happy the car is up & running.
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By GrantO
Hey great write up! Thank you :) 8-)

I’m hoping this’ll help me get my car up and running. I’m going through a similar thing and I was thinking perhaps I’d somehow broken the dual vr conditioner :lol:

I currently have a snapped bolt in my crank sensor bolt hole, and need to get a drill bit to take care of that :cry: :lol:
By tx_haggis
GrantO wrote:
Tue Jan 26, 2021 9:04 am
I currently have a snapped bolt in my crank sensor bolt hole, and need to get a drill bit to take care of that :cry: :lol:
Been there. With the engine in the car, it was a PITA :cry: Very difficult to get tools lined up with the bolt (I removed the sway bar). I tried a left handed drill bit, no joy. Ended up drilling out the bolt & retapping to M7x1.0 (because I didn't get the drill lined up right) - took it slowly over multiple evenings. It's not a common size, but it did fit through the sensor OK & survived multiple track days before I sold the car.

If I had to do it again, I'd remove the radiator as well as the sway bar to get better clearance. And buy decent drill bits & taps - it could have been retapped to M6x1.0 (the stock size) with enough clearance.
By tx_haggis
Just discovered the "Cold Advance" table - wasn't in the older firmware I was using. I'll swear in court I'd checked every menu item when we upgraded!

The cold advance was set to -15deg at all temperatures. Unlikely it affected the trigger settings, possible it affected the new ignition mode.

More testing needed.
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