Hondata

Hello. I have been facing the problem in many FN2 cars I tune. After some time on the dyno or some hard driving on the road, the ECU starts reading a lean AFR and starts adding extra fuel up to the max allowed 47%. This problem is also apparent with the stock calibration as well as MAF and MAP based tunes. Please find attached a datalog of the problem at idle, calibration used is stock FN2. Car is bone stock with just a cat-back.

Some FN2 owners have reported good results after changing the primary lambda. Some others have changed the secondary ECT sensor.

you have to post your calibration as well

This is a problem and I can't seem to figure it out. Car has only done 2000miles.

Try creating a new calibration and copy your tables to the new calibration and see if that fixes the problem.

Spunkster, the reason I did not post a calibration is because after trying virtually everything, I reverted the car to stock and just datalogged. So the calibration used is the bone stock calibration. So this might have nothing to do with the Flash Pro, may be is an inherent problem of the Euro FN2 ECU and/or primary o2 sensor. As I told you, I've seen this in 70% of the FN2s I tune. In most cases, the problem appears if you abuse the engine on the dyno and then goes away when you let it cool down for a while. In this specific car, the problem occured just after a dyno pull (aka very short time).

Now, in MAF based calibrations, there is no option to limit the short term trims (as in MAP based calibrations) or disable the primary o2 sensor. This could be a draft solution to the problem.

Any more ideas/experiences?

have you changed the lambda adjustment values in Fp manager?