The 4-stroke engine introduced fuel injection and simplified the involved task of jetting the carburetor when running rich or lean.

However, it also brought an electronic component to ensure the right ratio of gas and air that on the surface seems like another complicated piece of equipment that takes months to figure out and years to master. The ECU (Engine Control Unit), ECM (Engine Control Module), or CDI (Capacitor Discharge Ignition - replaced by ECU/ECM on modern engines) - all pretty much the same thing - controls the ignition and fuel system, whereas tuners allow you to tweak the fuel system and sometimes the ignition with the touch of a button.

The problem many riders have is the need for speed and the idea that turning all tuner dials to "maximum" means more torque and faster response. Actually, that's a great way to ensure a slow, sluggish and overall crappy ride.

Most EFI (Electronic Fuel Injection) programmers are "plug and play" meaning you plug them in between the ECU and the throttle body's electronics (injector and TPS) and this allows for quick modification of the stock ECU mapping. It's the same as jetting your carb, without jetting your carb and making adjustments to the pilot jet, needle jet, and main jet. Some tuners install and remain with the bike others unplug after programming. It's an on-board computer, in many respects, eliminating the need for expensive dyno testing. These basic "plug and play" tuners offer easy step-by-step instructions on how to map configurations for common situations. Yet, it sounds a bit daunting for some to handle this technology and others think it best to turn the dials to 11 once connected.

However, that can't work for your 2008 Honda CRF and work for your friend's 2012 Yamaha YZ, can it? So how do you use a fuel injection tuner?

Read the instructions.

Yes, it's that simple. We can't give you a step-by-step process on using a tuner because it depends on the individual set-up and the specific controller used. Keep in mind that not everyone needs a fuel management programmer because the stock mapping generally works for most riding applications. If you're not experiencing backfiring, hesitation, stalling or other intake and fuel control issues you don't need one.

FMF EFI Power Programmer

The big BUT here is whether or not you've performed any upgrades or other changes to your fuel or ignition system. We'd recommend an EFI tuner if you've done any of the following to your fuel injected 4 stroke or 2 stroke dirt bike or ATV:

  • Performance exhaust upgrades (pipe or complete system)
  • Valve train modification such as oversized valves, or aftermarket cams
  • Air Intake Upgrades (intake kit)
  • Big bore kits or oversized pistons
  • Changes to crank or rod stroke

In short, any modifications in engine displacement or valve train on a fuel-injected bike needs at a minimum a basic EFI tuner. These allow changes to the throttle position sensor, the injector and a few other sensors that help determine air/fuel ratio. More advanced systems (aftermarket programmable ECU) essentially replace the factory computer (stock ECU) allowing modifications to the ignition as well as air and fuel delivery. These units use the original ECU harness for installation. When installed, the basic EFI tuners position inside the airbox, attach to the subframe or locate under the seat or behind the airbox panel.

Honda PGM-FI Tuning Kit

The DIY EFI programmers include:

The more advanced ECU systems for the serious racer benefit most from a professional tuning mechanic with the use of a dyno or testing at the track:

Factory electronic fuel and ignition systems adapt to most conditions quite easily so if your friends race up a sand hill faster than you or you can't keep up in the C class, try some upgrades to your engine or exhaust system first then grab an EFI tuner to compensate for the changes.

Information is your best friend. Check out these related articles to help get you up to speed:

Written By: AndrewT