Hondata S300 Tuning Basic

After messing around with the Hondata S300, there are couple of things that I learnt and found out which may not be cover under the S300 help files.

Before commencing tuning:

1) Chk all sensors are in working order: TPS, MAP, IAT, ECT, Idling Solenoid Valve and RPM.

2) Set your ignition timing with ignition timing gun by adjusting the distributor to 16 Degrees

3) If u decide to run in close loop, then tune it in close loop by setting the Short Term Adjustment to 0% for minimum and maximum under Parameter -> Close Loop Tab. This will prevent the ECU from adjusting the fuel value with reference to the AFR reading. Once the tuning is complete, set the minimum short term adjustment to -30% and maximum to 30%.

The reason being, fuel adjustment in close loop are affected by quite a number of parameters besides basic fueling and ignition. In Open Loop tuning, there are just too many parameter to adjust to ensure it works properly in close loop.  This is why that people are complaining that when they complete tuning in Open Loop and switch back to Close Loop, their AFR readings are very different or not running as desired (usually very lean).  Some of the parameters the affects the fuel inputs are Fuel Compensation and Ignition due to IAT and ECT.

4) ALWAYS tune with Wide-Band AFR sensor!!  Dont even try tuning without this...

5) Try as much as possible to have a constant IAT (Intake Air Temperature) during your tuning.

6) Forget about using the Lambda Target table in the S300 for tuning.  It is inaccurate as it includes the AFR value when u throttle off, which usually will cause the average AFR value to much lower than it is actually is.

What I do when trying to obtain accurate AFR value, is to maintain a constant throttle and hold it till the AFR reading stablises. After which I will adjust the fuel value accordingly.

The guide is mainly for part throttle tuning/cruising. For full throttle tuning, I strongly believe it has to be done on the dyno machine.