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
• Work with no internet connection - VETuner caches itself on your device and keeps running in a garage or anywhere with no signal. See Using VETuner Offline

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. Using VETuner Offline - what keeps working with no internet connection.
3. Starting Your Engine - run first-start checks and use Focus Mode.
4. Configuration Health Check - understand the sanity checks VETuner runs on your ECU.
5. Start Doctor - diagnose no-start and unstable cranking behaviour.
6. Editing Tuning Tables - make safe table changes and burn/save correctly.
7. 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