use MS for logging ignition timing of *existing* ECU?

[OctaneMatt]

I have a 1.6L Miata and I would like to do some logging of the stock ECU ignition timing vs AFM, IAT, ECT etc. I'm not an EE but pretty comfortable with electronics and basic programming. Would some sort of MS variation be suitable for this? The only off-the-shelf solutions I have been able to find are lab-grade devices. Some of the Innovate Motorsports boxes used to do this but they dropped these features quite a while ago.

Thoughts?

Cheers,
Matt

[kjones6039]

Although I am not sure about timing specifically, an MS could certainly read and log any number of sensors. I do know that some users have had difficulty sharing sensors between MS and their OEM ECUs though.

Ken

[trakkies]

Just trying to think what you'd need to log an ignition map. Think you'd need two tach signals - one showing a fixed point like TDC and one reading the actual spark. And, I'd guess, special software.

[Bernard Fife]

OctMatt,

I wanted to log an OEM engine's variables (like timing, air flow, pulse widths, etc.) a few times, and it turned out that the easiest way was to get a $20 OBD-II reader off eBay (I think mine is elm327 based), and there's plenty of freeware logger programs for these on the web. I used that to log the signals (it will give you virtually everything you could want once you set it up).

Reconfiguring MegaSquirt hardware is going to take a lot of time, and then you would also have to write code from scratch to log the signals. That's because while MegaSquirt reports the timing, pulse widths, etc., it doesn't measure these. Instead, it is reporting what it commands these devices to do (just like OBD-II for the most part). If your time is worth anything at all, it really isn't worth it. Add that to the fact that it isn't too hard to tune an engine without any of that information (i.e. starting blind) by following the MegaSquirt manual.

Lance.

[OctaneMatt]

Thanks all for the responses.

I'm racing the car and have to retain the stock ECU, so I'm trying to optimize power by twidling with the AFM and fuel pressure. The AFM has some influence on ignition timing and I'm trying to quantify that influence, as well as see if there's any difference on the dyno vs track as the AFM flapper is influenced by g-loading. Any thoughts on a base project that might be a bit more suitable? I've searched high and low and surprisingly come up with no automotive projects that log (non OBD2) ignition timing.

Does anyone know if the tach signal corresponds to the coil firings? If that's the case then all I would have to do it measure the time between the cam signal and tach (picking the correct side of the signal and calculating degrees)? Here's one resource I found: http://www.rivercityroad.com/garage/ign ... nals_2.htm

Cheers,
Matt