There have been some interest lately in my AEM Infinity EMS install on my 2006 MX-5 so I might as well make an update.
I bought the AEM Infinity 7108 back in 2013 as I was not happy with tuning the stock ECU. I successfully tuned my 1.8 for E85,ID1000 and FI with the FMSC but the process was tedious and with lots of trail and error. As far as tuning goes it was a step back from any EMS I have been working with previously ( Link, Adaptronic, Hydra ). I could write a lot about why I think it's is a dead end for serious tuning but I'll save that for a later post.
The reason I ended up with the Infinity was :
- DBW support
- CAN bus support/integration
- Lots of inputs for logging external sensors
- Feature rich (all unlocked) options and tuning suite.
Since CAN was supported I aimed at replacing the stock ECU completely and mapped all input/outputs using the Infinity diagram and FSM. The layout and functions of the ECU's appeared very similar. I could reuse all stock power/relay related wiring, DBW worked on the first try. The only real challenges looked to be CAN integration and getting the PWM controlled generator to work.
Eager to verify that I could control spark/fuel I threw together a minimal harness.
But it did not fire. Infinity tuner showed no sync of the crank/cam triggers.
The reason was simple. I assumed it had 36-2 trigger wheel and a 1 tooth cam wheel.
But it actually has an awkward 36-2-2-2 crank and a 12-2-2-1-1 cam ( teeth) .
I never had the engine out to have a proper look at the crank pulley or cam. Also the GRC SuperCar Lites which uses a destroked MZR 2.5L uses the Infinity so I kind of thought it was supported. I later learned that they were converted to 36-2 / 1 using duratec pulley and custom cam. Crap.
But I was not about to give up yet.
So I registered a post on the AEM forum for a possible solution but they had no plans for the MX-5 NC trigger pattern support.
I got even more disappointed when I asked about doc on how to access the CANbus interface which is not end user configurable. That means AEM needs to make a fully supported plug&play application for that to happen. The NC market is not big enough I guess.
My last effort was to check with MazdaEdit if there was a possibility to reflash the stock ECU to change trigger pattern. NO.
So basicly I was stuck with an expensive box and a heap of wires not able to control the engine or anything relying on CAN bus (cluster, locks, hvac etc.).
Still not giving up I started googling about trigger pattern converters which exist for some rare applications involving new/old GM v8's and some AUS only Nissan stuff which was of no help.
That is when I learned about the ardu-stim project which is a Arduino based crank/cam wheel simulator that can be programmed to simulate trigger outputs. It's part of a larger project LibreEMS. Of course the MZR trigger pattern was not supported. But after a lot measuring and info back and forth via the LibreEMS support forum Mr. David Andruczyk implemented the pattern and I could now successfully feed the stock ECU with a preset rpm or sweep.
My plan was to convince the project of implementing support for a tach signal input or even reading one of the supported patterns as input and converting it to a new pattern for output.
While working on this I feeded some of the pattern descriptions and measurements over to AEM which I might have motivated them implement the trigger patterns as they a month later announced support for the MX-5 trigger pattern in the forthcoming V96.1 firmware ! That meant a parallel install sharing trigger signals might work.
But this was in March 2015 and the new firmware didn't get released until end of May. I was then focused on getting my current setup working with MazdaEdit reflash and restart the Infinity project in 2016.