Facts about Daihatsu Mira throttle body
When your mechanic tells.you that Daihatsu Mira L200 does not have a
throttle sensor hence air/fuel tuning is not possible, they're probably crapping
or they're not familiar with it.
The fact is..
The Daihatsu Mira DOES have a TPS (Throttle Position Sensor) but the TPS on a Mira is only an On/Off TPS (same like
what we've studied in logic, 1 or 0). Meaning to say, 0 Volts when the throttle is off and 5 Volts when the throttle is on;
even if you just touched it a tiny bit.
On a Potentiometered TPS has on/off feature as the Mira. Upon a little bit more throttle after "on", the voltage goes back
to 0 Volts. Then as you progressively step on more throttle till full throttle, you should get about 4.5volts to 5volts. So
wiring the throttle function in your Mira doesnt do anything as it does not have the progression of the potentiometer.
However, technically if you can fit a potentiometer type TPS to your L200 and still having the On/Off side hooked up to
the ECU, you might be able to get the piggy back air/fuel controller to work, but you would probably have to replace the
entire throttle body.
The disadvantage of this set up is that, if your vehicle is tuned for 14psi (1kpa or 1.0 bar) of boost, running less boost
might be a little richer than required. So to be honest, not much of a big deal as fitting a potentiometer type TPS, you will
get the air/fuel tuning to work, but the ECU would still have nothing to do with it.
To summarise that, myth said that air/fuel tuning is not possible on a L200 but the actual fact is, it is possible to be done!
Apexi S-AFC is a good economical start. The EF-JL management system does not run a TPS and therefore, you can't
tune your low throttle setting. However you can tune the high throttle at full wide open throttle, which may make your
mixtures slightly richer if you are running lower boost than what it is tuned for.