How did you adjust the mixture without a means of measuring the fuel air ratio. Or did you have such a means. Were you able to check exhaust pipe output
With the Omex ECU there is a closed loop system that gives feedback from the Narrowband Lambda sensor.
It does not give a direct reading of the air fuel ratio but it does tell you how much fuel the computer is adding or subtracting to get back to Lambda 1, i.e. the stoichiometric AFR of 14.7:1
If for example the ECU was showing minus 10% on the Oxygen Feedback (OXFB) readout, that means that the computer is deducting 10% fuel to get back to Lambda1.
That therefore means that the mixture is approximately 10% too rich in that particular load / speed site so simply reduce that mapping site number by 10% and play with it until the OXFB is as close to Zero as possible.
It's not ideal at the higher load and speed sites on the fuel grid as it is better to have a lambda of somewhere between 0.85 to 0.90 (i.e a richer mixture with an AFR between 12.5 and 13.2) for best torque and the Narrowband sensor will only read Lambda1.
However it does give a reasonably reliable indication of the mixture as a good starting point.
From there one can either work through a range of road tests using the data logging process ( which is what I think Gambalunga does) until the best overall configuration is found or use a wideband lambda sensor on a dyno to give a fairly accurate map and then refine it slightly after the road testing.
Both are equally valid but the wideband dyno system gets there a bit faster.
As Gambalunga will attest to, I think, this adds a whole extra dimension to Morgan ownership and engine tuning in general.