The inputs checklist
- Throttle position sensor (TPS). Tells the ECU how far the throttle is open. See TPS input.
- Coolant temperature sensor. Drives warm-up enrichment and many safety strategies.
- Air temperature sensor. Lets the ECU correct for air density. See inlet air temperature.
- MAP sensor. Essential on boosted engines; optional on many naturally aspirated ones.
- O2 sensor. Optional, but a wideband makes tuning far easier and safer.
- Crank angle sensor to Trigger. This is the ECU's main engine position signal, often called the crank trigger. Some engines drive it from the cam, but it still reports crank position.
- Cam angle sensor(s) to Home, where fitted. This tells the ECU which stroke the engine is on.
Leave room to change the trigger wiring
Don't permanently seal, tape and loom the Trigger and Home connections until the engine is running and the trigger is confirmed. It's common to need to swap signal polarity or move a wire during setup, and that's much easier with the wiring still accessible.
For more detail on the position sensors, read trigger wiring. Once inputs are done, move on to the outputs summary and power and ground wiring.
