Megasquirt, part 6

Well, I have missed my target installation date. I finished the base build yesterday, plugged in the 'stim, powered it up, LEDs started flashing... but not in anything like the correct order. It made me sad for a little while, but then I suspected the power supply was a little too weedy (9V 200ma), so dug out a 600ma one and it worked perfectly! My little face was smiling again!

Next step was the ignition mods, you can see them in the picture below. Annoyingly, the 330 ohm resistors required don't come in the kit, and nor does the 0.1uf capacitor required. The whole lot only cost 64p from Maplin though. Note that once you've made these mods, the 'stim tests no longer work properly. This confused me, I thought something was wrong so reversed them, but it's correct - the 'stim can't simulate the CAS so you get no tach signal, hence no injectors.

This is the point to install the required firmware. The system comes with the standard fuel-only firmware, you have to replace that with the MS1-Extra which adds (amongst other things) ignition control. I have spent hours researching that this weekend, and this is my solution for a stock car:
  • Download the MegasquirtPnP tuning software from DIYautotune (presently MS_PNP_Setup_021108.exe)
  • That will create a folder structure, C:\Program Files\MegasquirtPNP\MSpnp_MM9093 with MAF, or similar.
  • Run the DownloadFirmware.bat file in this folder; you'll be prompted to power up the Megasquirt and insert the boot jumper (left of the CPU). Don't be like me and forget to actually put the CPU in!
  • This will write the MS1-E firmware to the chip; it will take a minute or so.
  • Remove the jumper and reset the Megasquirt
  • Run Copyini.bat to complete the process

Now you need to run the Megatune .MSQ file you'll find in the same directory; this contains the config for the MX5. Write it to the CPU when prompted. Now with the 'stim attached, you should see almost everything working again, though there is still no working RPM.

Next steps for me are the fan mod (control the cooling fan) and boost controller. Both of these are to be built in the prototype area, still a big foggy on the details though. I've got to wire up the harness too, I've looked at the car and the wiring is as shown in this extremely useful thread on MiataTurbo.net.

So not a great deal done then. I'm blaming the dreadful weather, where did summer go?

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