Electronic fuel injection (EFI) uses an electronic controller, sensors and an injector to meter fuel for an engine. For UAV engines, it provides a way to calibrate fuel delivery across operating conditions and, where supported, monitor engine data through a telemetry link.
EFI is not a guarantee of lower consumption or trouble-free operation. Its benefits depend on the engine, hardware, calibration and installation. This guide explains what to assess when comparing EFI with a carburetor.
How electronic fuel injection works
The ECU calculates injector operation using a calibration and the available sensor inputs. The location of the injector depends on the system architecture: throttle-body, port and direct-injection systems should not be treated as interchangeable designs.
A carburetor meters fuel through its mechanical arrangement. EFI moves that metering task into an electronically controlled system, which introduces its own requirements for electrical supply, sensors, wiring and calibration.
Starting and operation across changing conditions
A suitable calibration can address starting, warm-up and normal running separately. The settings must be validated on the selected engine and fuel, including the conditions in which it will operate. EFI does not make every hot or cold start automatic, and does not remove the need to check the fuel and ignition systems.
Pressure and temperature inputs can support fuel compensation as ambient conditions change. The available sensors and compensation strategy must be confirmed for the ECU. Changes in altitude also affect the engine’s available performance; fuel compensation alone does not eliminate that effect.
Fuel consumption must be measured at comparable operating points
A well-matched calibration can help avoid unsuitable mixture settings, but a universal saving percentage is not a sound basis for selecting a system. Compare the same engine configuration, fuel, load and operating conditions, with a documented measurement method.
Our guide to brake-specific fuel consumption for UAV engines explains how fuel mass flow and measured mechanical output relate. A single consumption figure without its operating point can be misleading.
Telemetry helps make engine behaviour visible
Depending on the ECU and interface, engine data can support monitoring and diagnosis. Confirm the actual fields, update rate and functions available in your configuration. Receiving telemetry is different from commanding engine operation.
ArduPilot’s EFI documentation describes several supported integration routes. Compatibility must be checked for the specific controller and firmware; it is not a blanket statement that every EFI supports the same connection.
What to check before converting an engine
- Exact engine model, fuel and lubrication requirements.
- Intake dimensions, throttle-body mounting and installation clearance.
- ECU, pump and accessory power requirements.
- Calibration scope, test conditions and support for the selected configuration.
- Required telemetry and engine-control functions.
Explore Löweheiser EFI systems, consult our engine conversion reference, or compare EFI engine options.
Discuss your application
Send us your engine model, intended fuel, operating requirements and available installation details. Discuss your configuration with Löweheiser.
English 
French 
German
It was quite informative when you told us that electronic fuel injection is a system that directly injects fuel into the throttle, which is suitable for small UAV engines that need an easy start and better fuel efficiency. I imagine if you own vehicles needed for your business, it would help to have an EFI system to use for them to properly manage your fuel source. I’ll keep this in mind in case I ever need fuel injection in the future.