XNWRX

does anyone knows what kind of signals are needed on MY02 WRX/STi to control ignition and Injectors ?

I mean for each :
- is there a requirement to provide Power (voltage and current required) or is it high impedance (then what voltage) ?
- is it negative or positive logic ?
- is it a "load switching" process like the boost solenoïd (then switch the load to +12V or to ground and what current is needed) ?

Any help will be appreciated
Cheers,
Xavier

David_Wallis

Ecu switches ground's.

Injectors are are PWM I assume.. with varying pulsewidth between 0 & 100% (theoretically you could go beyond 100% duty by holding the injector open when the valve is shut.. ie spraying before the valve is opening.. (whilst on the top most of the exhaust stroke) iirc.

All voltages are 12v afaik.

David

XNWRX

Thanks David.
Are you sure ECU switches to ground ignition signals ?
I'm going to play with it and as you know, any error in my electronic can end with a desaster !

I'm surprised to hear that injectors would be controled by PWM. I'm would have say that they are kept wide open during a period of time relative to engine rev (100% corresponding to half a rev)...well, that can be seen as PWM.

More details ?

john banks

PWM with the period of the engine, so you are meaning the same thing.

Andy.F

Injectors are not PWM in the strictest sense, they are variable frequency timed pulses as opposed PWM being fixed frequency with width modulation.
Anything over 40% IDC and you are spraying on a closed valve as the 100% time available is for 2 revolutions of the engine. Even Davids lumpy intake cam is only open for around 270 degrees out of 720 available. In fact you are probably always spraying against a closed valve as the Injector on time can start before the intake valve opens even at idle.

Injectors and ignition are controlled by ECU switched grounds as far as I'm aware.

Andy

XNWRX

Thanks all, I'll try some tests and let you know