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. 

S300 ECU swap

Just got a P28 ECU prep by HA Motorsports for the S300.  My Hondata S300 is working fine with my current ECU.  But there is a reason, why I decided to spend the money to get a professionally done P28 for the S300.

Top: HA Motorsport P28 Below: Old P28

Old (left) and New (Right)

Old (bottom) and New(Top)

The reason for the swap is show in the pics below.

Old P28

Above is the picture of the board of the old P28 I was using.

Look closely and u will see the shoddy workmanship on the board. The soldering around the capacitors is really bad.  

To me it is like a time bomb, u never know when a circuit like this will fail!!

HA Motorsport ECU for S300

The circuit board and capacitors looks really new!!

S300 Module

S300 module installed!!

Hondata S300 and IAT compensation (IGN)

The previous article I mentioned that the Fuel Compensation for IAT was affecting my AFR readings.  After more datalogging and observations, I found that the bigger culprit was the Ignition Compensation for IAT.  Essentially it was retarding the ignition once the IAT sensor reads 51C and above, resulting in the leaning of the engine.  The leaning did not reoccur once I made adjustments to the compensation values.

However, the best way is still to relocate the IAT sensor to the air intake pipings like in the EKs instead of the intake manifold.

Hondata S300 and IAT compensation

More to share on tuning using S300.  

Background: I was tuning my car for part throttle (cruising) and managed to have a stable 14.7 AFR reading through column 1 to 5.  However after I shut down the engine for a while (couple of hours) and drove again,  I got lean readings (greater than 14.7).  I was expecting richer AFR than 14.7 rather leaner reading as the engine has cooled down.

I did a datalog and realised that the IAT readings were quite high which caused the ECU to reduce the duty cycle, resulting in a leaner AFR reading.  This might be the IAT sensor being heated up by the hot intake manifold.

2 lessons learnt:

1) When tuning your engine, try to make sure the IAT and ECT values are the same for each run as it affects the AFR value greatly.

2)   If possible, try to find a way to insulate the IAT sensor or minimise heat transfer from the Intake Manifold to get a more accurate reading.

Once u manage to tune your engine as desired (with constant ECT and IAT values),  you can adjust the fuel compensation for IAT and ECT accordingly since the default value may not be the ideal compensation required.

Hondata S300 closed loop operations

Since I had the S300 installed and tuned for more than one month ago, I have been trying to fine tune the fuel.  The main problem that I had was to enable closed loop operation after I have complete my open loop tuning.  The AFR runs really lean (17.0) after I enable the closed loop operation even though AFR reading during open loop operations were fine.

After going through the Hondata forum, I found some solution.

1) As the car was usually driven in closed loop operations, the ECU would have Long Term fuel trim inputs which will affect the duty cycle. The solution is to reset the ECU before tuning.

2) The symptoms above which I describe apparently affects only some ECU, the work around is to set the short term fuel trim settings under the closed loop tab to 0 for both maximum and minimum short term adjustments and tune the car in closed loop operation instead of open loop operations.  (remember set the values back to the original after completion of tuning)

3) Next is to adjust the Rate of change to the recommend setting by hondata as below:

This will minimise AFR fluctuations, thus improving drivability and milage.  The settings that I used was 5 for all slow value and 99 for all Fast value. 

Plse note: The tuning done on my car was based on the PLX wideband AFR.  Plse do not attempt to tune the car without at least wideband AFR, however u may try altering the rate of change even without a wideband AFR.

Definitions:
Short term fuel trim is the amount of fuel adjustment made by the ECU depending on the AFR reading

Long term fuel trim is the amount of fuel adjustment made by the ECU based on the average Short Term fuel trim made over a period of time

Rate of Change is the rate of change of fuel trim made by the ECU.

HONDATA S300

I had the Hondata for a while, but didnt get to install it and dyno-tuned until recently. I was running on APEXI VAFC2 beforehand.  

(Yes I know, the wiring is kind of a mess due to the VAFC2.  I will be getting it tidy up soonest.)

I am impress with the S300 due to the amount of parameters that be controlled. through the ECU. Simple stuff like things like Fan operating temp, idling fuel trim with respect to coolant temp, A/C switch off rpm, datalogging etc.  (Note to POWERFC Fans: POWERFC may be just as good or better, but I didint get a chance to play with the Tuning Program ;p)

The result after the dyno-tune was 11hp increase in horsepower and 10nm increase in torque, but u will also notice the drop between 5000-6000rpm range, which most likely mean that I have to it road tune too.

At the same time, I did find the engine was running a bit rich beyond 5000rpm at AFR 12.0 (Although it was running at 11.0 - 12.0 with SAFC2 before the tuning), so I decided to lean the fuel over  5000rpm band to AFR 12.5 which resulted in better response and power (butt dyno ;p). 

I would like to lean it further to 13.0 but I will only do that when I am able to monitor the exhaust temp.

I must make it clear that the original SAFC2 in my ride was only road tuned and it was doing well in terms of power and fuel economy.  But I feel that due to the original ECU close-loop functions, any tuning done on the SAFC2 will not be accurate in the long run. (however, a simple reset of the ECU once in a while will overcome this issue I guess)

OBD1 ECU Plug - Pin Removal

I have recently acquired a Hondata S300 and realised that it can have additional signal inputs (Sensors, secondary fuel map activation, etc).  To have such functions, I had to add additional pins inputs to the ECU plugs. I managed to get a spare ECU plugs for the pins.

I tried to google for instructions on how to do this, but I only manage to find vague answers to it.  For example: insert pin - wiggle pin both ends while pulling to remove pin... So I decided to have this how to when I figured how to remove the pin effectively.

This is one of the EG OBD1 ECU plug. I have removed most of the pins except two of them for this how-to demonstration.

First of all, u have the unhook the 'clamp' at the back of the plug.

Use a small flat screw driver to unhook the catch.

Once u are done, this is how it looks like from the back.

Insert a paper clip from the front to lift up the catch and plug the pin from the back.

This is how the pin is being held in the plug. Insert the paper clip (blue in the diagram) from the front at a angle and feel for the catch (black) , lift it up and u will be able to remove the pin easily.

Thanx to Amos again for the spare OBD1 ECU plugs :).