Nowadays, fuel injection is gradually replacing carburetors, which leads to a significant reduction in air pollution.

The benefits of fuel injection are plentiful: improved cold starts, considerably higher fuel economy, increased engine output across the powerband, etc. Regulating the fuel delivery on a continuous basis reduces engine overheating, improves throttle response under acceleration and optimizes the power delivery based on the load carried by the vehicle. But how does it work?

Many generations of fuel injectors have been introduced since the system was first invented. Motorcycles began using fuel injection in the late 1970s and manufacturers have kept improving the technology ever since. Here, electronics have played a huge role. Near the end of the 1990s, fuel injection made its way to all-terrain vehicles (ATVs).

Operating parameters
Several parameters determine the exact quantity of fuel required to ensure proper engine operation and full combustion. It all starts with the onboard computer, also known as the ECU, which analyzes the various data collected by the probes and sensors.

Depending on whether the information comes from a probe or sensor, the ECU calculates values in volts or variable resistance. It works pretty much like a team: every unit has to be activated, operational and in good shape. The computer monitors the status of each probe and sensor and then, if everything is normal, it activates the operating system. Pre-programmed mapping is used to control the start and duration of the injection process in relation to the data collected by the probes and sensors.

If one of those is reporting a problem, the computer will send an error message to the dashboard by flashing a warning light. This signal is similar to Morse code, except that numbers replace letters. These numbers allow the technician to identify exactly what went wrong (the source of the error). For example, a light signal made up of a single long flash followed by two short ones will be read "12". The technician will know what and where the error is, making it easy to find the faulty component and confirm the problem.

In some cases, the code will be displayed directly on the LCD screen of the ATV. The technician will have to perform a specific inquiry using an electronic monitor (Labscope) and the manufacturer's repair manual.


Reading parameters
Many control points operate simultaneously. These controls come from the probes and sensors. Factors that are taken into account include air, coolant and engine oil temperature, air pressure, engine speed as well as camshaft and throttle position. In some cases, the actual speed of the vehicle and the selected gear will also be factored in.

All of these serve to modify injection time and opening duration. As a result, the air-fuel mixture is injected with extreme precision into the intake manifold. Of course, at this stage, the computer controls everything based on said pre-programmed maps. Some manufacturers even offer upgraded chips to obtain additional power. There are also electronic modules, like the Dyno Jet, which increase power through various adjustments.


Photo Credit : Henri Lebarbé