DIY – Toyota Starlet Tacho Modification for Standalone ECU’s
A common issue for anyone wiring a standalone ECU into their 90’s Toyota Starlet is that the tachometer will not work if you replace the stock ignition system and try to drive the tacho with an output on a standalone ECU such as Link, Haltech, ECUMaster etc.
The reason this doesn’t work is because the tachometer is driven by a high voltage output (upwards of 40v) from the stock ignitor and most aftermarket ECU’s will only output a 12v+ square wave.
In this article I’ll explain how to modify your tachometer to allow it to be driven by an ECU output.
Soldering
If you are new to soldering or self taught, I would highly recommend you watch the EEVblog videos on soldering. Before watching these myself I was “self taught” and I really didn’t have a clue what I was doing but these videos changed all that. I would highly recommend investing some time in learning how to solder properly before you attempt this task!
Tools and parts required
- Screwdrivers – Flat heads and philips heads to remove and disassemble the tachometer
- Soldering iron – basic one will work fine but if you can borrow or purchase something better then I recommend it (see the video series above on recommendations of brand/model)
- Solder wick (or another way of removing solder)
- 1k ohm resistor