This is a section of a support leter I wrote a while back. I will edit it to make it more generic in some areas and more specific in some other areas.
Check TuningSession/VEtuning for notes related to the improved procedure, closed loop tuning
Tuning guide:
First of all, you have far too many load bins. It will make the tuning time consuming. I suggest that you put load bins at: 20, 30,50, 70, 90, 102, 120, 140, 160, 180, 200 and 250 kPa. These are the ones I have always used in the Autronic and they work well.
It's very important to understand that any WBo2 readings taken when the engine has missfires, bogs or just acting strangely is unlikely to be correct. For example a missfire reads lean (no matter how much fuel is injected) ! because the sensor only measures burned petrol, liquid petrol is ignored and only the air will be measured. Under conditions like this you need to read the plugs to get it right.
I also suggest that you disable closed loop lambda control: Settings->EGO(Lambda) control. Set Lean limit(%) and Rich Limit(%) to close to 0 (eg. 0.5%). This way the authority range is very narrow, you have total control, but you see immediately which direction to change. With a higher ego_lean_limit (usually 10..20%) the advantage is that you see in advance when you're approaching the desired VE (not just at the last moment, when you go leaner than you liked). In any case, you are recommended to review logs, but with EGO correction=0% you have to look up the desired lambda for every loadsite (and compare with actual lambda, and calculate the necessary correction), while with non-0 ego-correction the controller does the lookup and calculation and you can judge the situation immediately by looking at the ego-correction.
We start with the extremely low(-power) load sites.
Start off by letting the car idle, now tune the VE at the loadsite the engine use until the actual Lambda is the same as the target lambda (the value in the Lambda table under Settings-> Lambda table). No need to be anal about this, within 0.02-0.03 is good for now. You will probably need to blipp the throttle a few times to clear up the engine when doing this, especially when going from a pig rich base tune.
Now increase the RPM somewhat, 2k or so is fine. Do the same here, tune VE until the actual AFR is the same as the target. Same 0.02-0.03 applies here. Continue doing 3k in the same way.
We assume that the injector opening modeling parameters are ok, they probably aren't but as your injectors are very small it won't matter as much as if you had 1600cc injectors as some ot the other customers. have :) Learning to tune with the small injectors will make it much easier. Comment made about 200cc injectors -JK
You can now copy the value you have at 3k to 4k and so on all the way up to your higest rpm site. Now copy the low load sites upward toward 70kPa load or so. Normally I would go to 100kPa but as this is time consuming in megatune it's enough with 70kPa. You will do the 'copy upward' routine several times and doing it all the way to 100kPa every time in megatune will SUCK :)
It's now time to take the car for a spin, mentally prepare yourself to hold a few load sites and start the logger. If you still have the load sites from the msq file you sent you want to log these for five seconds steady state each: 50kPa: 1100rpm, 1600rpm, 2200rpm, 2800rpm.
Now check the log and compare the actual lambda and the target lambda for each of the tested sites, actual lambda/target lambda will give you a multiplier that you need to apply on the load site. After making the corrections on the above sites you copy upward and to the right. Now repeat the above 50kPa loadsite to check if the change was enough or if the sensor was bottomed out.
When the 50kPa sites above is tuned fairly well you can go to the next three rpm sites, still at 50kPa: 3400, 4000, 4600. Again copy upward and to the right after going through the 'test, adjust, test' cycle.
You are now ready to go to the next load level (70kPa) You need to be more careful now as problems can start causing engine damage now. Just let it run steady state for 2-3 seconds or so on each site the first time until you know that you are starting to home in on the settings. You also need to listen for detonation now and read the plugs for signs of detonation between the runs.
Now repeat for the remaining load sites.
The above assumes that it's a one person tune, I guess that most of you are stuck with that as the assistant or 'laptop jockey' has to be the one that is the better tuner and is the one in charge over the guy driving the car. I don't trust anyone and when tuning my own car I always use the 'one man tune procedure'.When doing a two person tune you can use the tuning screens in the 'Tuning' menu of megatune.
The next step:
This is where you enable ego correction if you choose to do so, or where you start to compensate for ego correction if it has been activated during the tuning process. In any case ego correction should be activated from now on. It is very important that the WBo2 sensor is calibrated now and that the ego correction limits are correctly set.
Make sure that the engine is properly warmed up, this includes that the oil temp is in the working range.
With the logger running you go out and run the car for a few seconds on each of the load sites, you don't have to make it steady state, just letting it accelerate slowly through the load site works well. I hope that you have long steep hills nearby :) You want to be strategic when you do this, try to run steady load (kPa). It is very important that you don't make sudden throttle movements as that will disturb the readings. Smoothness is the keyword here.
After collecting data for the load sites you sit down and check the log, this is best done in the comfort of your office with a notepad at hand.
Identify the load sites you have been holding and check the ego correction column for each of them. IIRC its called 'Gego', 100 is no change and below 100 means that it has been a negative correction. traditionally on WOT closed loop systems you try to keep the correction below 7%, in other words you want Gego to be between 93 and 107 at all times.
This secion can be pretty tricky as the ego correction is used to compensate for the intake air temp changes after the sensor and many other things that is hard to tune. You'll also notice if the ego correction parameters aren't optimal at this point, I have spent hour after hour dealing with these parameters on FAST engine management systems.