Stock AE86 Rev counter

[gunni]

Can I share the 12v that goes to the relays turning the ECU on and off, or will the tacho wire from the ECU make the power relays turn off?

yes you can,
they will not.

[rob@vems.co.uk]

Ok thanks, is there a rule of thumb of what resistor to use? Or just try one? Like 330Ohm

You want to use the largest resistor that still works as you want to keep the current as low as possible.
I = V/R = 13.8/330 = 0.0418

[Will]

Tried a 470ohm one, so going to go out and buy some lower value ones and give it ago.

O I'm using pin 6 of the 36pin plug.
Do I set the tach output to Inject channel 6 or 7? As I have read that pin being referred to both name.

[gunni]

I´ve always used a P259 channel.

And I have normally used a 1kOhm resistor but have had a 2k one work.

[rob@vems.co.uk]

Tried a 470ohm one, so going to go out and buy some lower value ones and give it ago.

O I'm using pin 6 of the 36pin plug.
Do I set the tach output to Inject channel 6 or 7? As I have read that pin being referred to both name.

If 470 worked use it, 40mA is fine through a p259 channel

Rob