How the 4A-GE ECU works

[JMR_AW11]

NoHachi Wrote:Or just add a separate knock retard unit..You really don't want the ecu controlling knock unless you are running an Ion sensing setup. Basically you just want to tune the engine to a safe margine under the knock threshhold, and then have a sort of limp home function to cut in whenever it does pop up. Diagnose the problem, solve it and go back to std running mode..

I doubt whether the stock ecu will be able of handeling positive MAP. The sensor doesn't.

I think the ECU can handle positive MAP as all it sees is a voltage range at the input PIN. Just remap the existing tables to suit the new MAP sensor.

The ideal solution would be to have a new MAP sensor that 'carried on' a bit above the old one. I could easily extend the tables in the ECU to give a bit more range.

Also there is another 'secret' in the UK 4A-GE ECU I haven't told you guys.

There is a hidden two wire interface to the ECU MCU which allows you to alter the ignition timing in 4 steps using an external switch.

Form memory I think it was 0deg, +2deg, -2deg, and -10deg. The stock ECU supports this function.

It would be easy to add a standalone knock sensor unit to this interface.
Obviously with my retuneable ECU the adjustment range could be enhanced...