Alright this is going to be a long one but will try and keep the wordiness down as much as I can, nobody wants a wall of text but have tried a lot before coming to you guys.2000 miata has been on diypnp for like 10-15 years. Ran OK on just wastegate but never got car completed enough (couldn't ever get bigger injectors working so went back to stock, leaks, suspension stuff, manifold/exhaust problems blah blah) to the point of being able to turn it up and properly dyno tune it. End of last year I worked to get it back together/going mechanically and in October the car was running and happy. I was finally ready for the last step, upgrading the injectors (flow force 640) and tuning for them.

Fast forward a few months after the garage got back above 20 degrees. I bought the 640s and I wanted to get ready to tune for the injectors but my 15 year old laptop was fubar. Set up a new laptop, set up new version of tunerstudio and decided hey let's get the diypnp on the latest firmware before I start all this, it's quite old. I went through upgrading the firmware and then all hell broke loose. Cranks and cranks no start, I turned to ChatGPT (def could have used THAT 15 years ago) and went through a bunch of troubleshooting. I had it summarize my steps to keep this shorter, I can expand on anything, grab any logs, check whatever you might wonder about. But basically uncovered my cam and crank sensors are pulsing at 1-1 instead of 4-1. On the 3.4.4 firmware I wasn't even getting a cam signal.


Here’s a timeline of everything I’ve tried so far to troubleshoot my persistent no-start/sync issue.

1. Initial Setup & Firmware Upgrade
   • Car ran fine on an older MS2/Extra firmware (3.1.0).
   • Upgraded to a newer 3.4.4 firmware (MS2/Extra).
   • After upgrade, the engine would crank but showed no RPM in TunerStudio; never synced.
2. Checked Tune & Ignition Settings
   • Re-confirmed Miata 99–00 spark mode, Rising Edge input capture, Going High (Inverted) spark output, Wasted Spark, 10° offset.
   • Tried flipping Rising ↔ Falling Edge; no change in sync.
3. Tooth Logger & Composite Logger
   • Observed pulses in the Tooth/Composite Logger, but discovered a 1:1 ratio between the crank (blue) and cam (red) signals.
   • Expected a 4-tooth crank + 1-tooth cam pattern, but instead both lines pulsed at the same frequency.
   • This indicated the ECU sees two separate inputs but not the correct 4:1 pattern, preventing sync.
4. Rolled Back to Old Firmware & Old Tune
   • Flashed back to 3.1.1 firmware (couldn't find 3.1.0) and reloaded the old MSQ.
   • Still saw the exact same 1:1 crank/cam pattern; no sync, no RPM.
5. Loaded a Fresh Base Tune
   • Grabbed the official 1999–2000 Miata DIYPNP base tune from DIYAutoTune.
   • Set up basic calibration (TPS, IAT, CLT), set “Miata 99–00,” Verified ignition settings, disabled noise filtering.
   • Cranked again—still 1:1 in the Composite Logger, no sync.
   • Reverted back to previous 3.1.1 tune

ChatGPT thinks it's likely a crank sensor, cam sensor, or wiring/board jumper issue causing the ECU to see only one pulse per revolution on the crank (matching the cam). Nothing changed physically and I inspected the 4 tooth wheel and sensors, everything LOOKS ok and it's getting at least SOME signal so I find it hard to think it happened to die during the firmware upgrade. Nothing has changed from wiring or inside the DIYPNP but if I really need to I can pull it out and inspect stuff. I'm attaching the tune, composite logger and screenshot but I'm obviously an idiot with this stuff so I'm happy to grab whatever I can to help, any advice is appreciated!

 

You are missing the cam signal entirely. The red is error, not cam. Blue is crank, green is cam, red is error. You have no green.

 

Ahh thank you Reverant. That makes way more sense than cam and crank being at the same time. Still have to figure out WHY but that gives me something specific to look into.

 

So, little update. Still not sure where to go from here. I have replaced the cam sensor, no change. Pulled out the ecu and checked continuity all the way from the harness 3H pin to the vr2 pickup connector and is good. Verified resistance of the 470 (was like 466 on the board) resistor on the pickup just because. So I THINK the wiring is ok? Or do I need to go farther and trace leads wherever that vr2 goes?

Inside the car I have verified continuity between the 3h pin on the harness connector and the cam sensor connector. Verified that with the key on the sensor connector is getting 12v. I'm getting 0.0 resistance on the ground pin in the connector. So I THINK that rules out wiring? But I've "ruled out" wiring, the sensor, the connector and the Ecu so surely I'm missing something?

I'm sure these aren't helpful but feel free to have a laugh at my soldering from 15 years ago. Looks like one of the inj2 wire sheathings have melted a smidge but isn't touching anything. CLT and TPS wires look friendly but both of those were working.

 

It's alive!
Figured I had checked everything and had to have done something wrong, firmware was the only thing I could think of, so started there. Turns out I had used the wrong firmware s19 when I upgraded. Not sure why going back didn't work maybe I got the wrong one there too but going forward to 3.4.4 and using the microsquirt-module fw worked. Idk I even ran the terminal command to check it but I think the confusion came from there not being a version named microsquirt in older versions? At least I don't see one if I go look at the 3.1.1 download folder.

Anyways, just wanted to check back in and provide an update on my fix since all the threads I found searching never ended with an answer. At least this one fixed my issue. It runs like **** (after checking the tune, don't currently have an idle valve so probably lost that setting in the fw upgrades) but I can research and work through all that. I'm sure I'll be back again when I get stuck

 

Just went through this with an ancient microsquirt on a Lotus 7 rep. Firmware looked like the stone age, I know MS pretty well, and it was damn near untunable. I think I found a few versions newer that was labeled obsolete in 2015, don't even want to know when the original firmware became obsolete.

Anyways, any update to recent firmware made the EDIS (basically crank with simulated cam sensor) no longer sync. Very frustrating, ending up swapping for one of these, just to have modern firmware:

https://www.diyautotune.com/product/...xoC_GkQAvD_BwE

neat little option if you need a MS and don't need an PNP model.