VETuner

VETuner is a browser-based ECU tuning application for Speeduino and Megasquirt ECUs. It runs entirely in your web browser; no software installation required. Use it on your phone, tablet or laptop.

What can VETuner do?

• Connect directly to your ECU over USB or serial using the Web Serial API built into Chrome and Edge
• Start Doctor Watches you as you crank your engine, diagnoses common problems and offers advice on how to get your engine running and idling
• Read and write tuning tables (VE table, ignition advance, AFR targets, and hundreds more) directly on the ECU
• Visualise real-time data with live gauges, a configurable dashboard, and colour-coded heat maps
• Analyse volumetric efficiency by recording a drive log and letting VETuner calculate the adjustments your VE table needs
• Monitor external sensors over Bluetooth - connect temperature probes via Shelly Pill and display readings alongside ECU data
• Load and save tune files in the standard MSQ format, compatible with TunerStudio

Getting started

Choose a topic from the navigation menu, or jump straight to Starting Your Engine if this is your first time.

Suggested reading path

If you are new to VETuner, follow this sequence:

1. Connecting to Your ECU - establish a stable connection and verify serial comms.
2. Starting Your Engine - run first-start checks and use Focus Mode.
3. Configuration Health Check - understand the sanity checks VETuner runs on your ECU.
4. Start Doctor - diagnose no-start and unstable cranking behaviour.
5. Editing Tuning Tables - make safe table changes and burn/save correctly.
6. VE Analysis - automate VE correction once the engine is warm and stable.

For theory and deeper tuning concepts, continue into the Advanced section:

• Volumetric Efficiency Theory
• The Fuel Equation
• Lambda and AFR
• Ignition Timing Theory
• Closed-Loop Fuel Control
• Data Logging for VE Analysis