Tach Signal on Mitsubishi
The stock RPM meter has one wire towards ECU. I tried to tap it to one of injector channels, and added it to all h[0] masks. The gauge was working properly but there are two difficulites:
- Right now I use all injector channels, so I don't have free inj channels anymore
- No tach signal at deacceleration (decel fuel cut), so gauge shows 0 rpm at decel
Configurable tach output was made for this
You can simply connect a free
- injector output (or even the flybackless 2nd WBO2 heater output)
- or p259 output
- or stepper output
- or ignition output
If RPM needle rests at 0....
A 270 .. 2k4 resistor pullup (to +12V) can be tried (assuming they forgot it from the RPM gauge input). Not much risks here (any output can take 12V through 270 Ohm or higher limiting resistor without damage).
If RPM needle rests at 0....
If an RPM gauge originally got the input signal directly from the primary side of the ignition transformer, or you know the gauge needs high voltage to trigger, the above will not be enough for RPM signal. In this case...
Take a free ignition (not logiclevel, but IGBT) output (on Roland's ALS BMW 1.6 turbo we used EC36pin10, that is i259 channel 7 as seen on GenBoard/Manual/DigitalOut/Table), configure tach_channel and used an "inductive pullup" to 12V made from a [22 Ohm and 220uH] connected in series.