The ECU (Electronic Control Unit) is basically a device in the
engine to determine the optimum fuel to be used. This is supposed
to be better in terms of fuel efficiency and performance. I'm not
really sure if you mean clearing or cleaning but clearing the ECU
would mean clearing or resetting the control codes in the ECU and
reprogramming it. Something like a format of the computer and then
upgrade to the next better version of the OS.
As for increasing the tacho range, what do you mean, in real life
or ID? In real life, that's illegal in Singapore. In ID, only the
AE86 can do this, I think you need to use Tune A and reach a
certain number of points. At least that's what my friend told
me.
