Begin by following the ‘Quick Start Guide’ that comes with the LM-1 / LM-2. If you lost that or need a copy of it for some reason you can download it here: LM-1 Quick Start Guide
LM-2 Quick Start Guide
In addition, DIYAutoTune recommends:
- If you are simply using the LCD display on the LM-1 / LM-2 to tune your car you have nothing different to do. However, if you are routing an analog output from the LM-1 / LM-2 into the MegaSquirt you should ground the LM-1 / LM-2 and the MegaSquirt at the same point. This is to prevent a voltage differential and will ensure accurate readings. You might even clip the cig lighter connector wire that comes with the LM-1 / LM-2 and put quick disconnects on it, and install the same type of quick disconnect connectors on the MS Harness so I can pull power and ground from the same source it pulls from, ensuring the MegaSquirt gets an accurate sensor reading.
Note– You do not ever need the 470 ohm resistor with the LM-1 or LM-2.