ECU and EFI system Upgrades for Fuel Injection Vehicles and Engines

  • Again the basics, the fuel injection system runs on pulses of electricity to fuel injectors inside the engine. The fuel injectors do not care where the impulses come from, and will energize as long as their voltage and amperage minimums are achieved.
  • Fuel injectors are designed for higher pressures than manufacturers specifications.
  • Fuel pressures at ridiculously high numbers are not outside operational tolerances for many fuel injector models.
  • Therefore most fuel injectors are already a performance part in your engine.

    Remember that fuel system upgrades will affect the fuel efficiency, mileage, and emissions of your vehicle. Please adhere to all rules and regulations regarding emissions, noise, and horsepower in your area.

    ECU Chip Upgrades

    This is the easiest fuel injection computer upgrade available for most vehicles and engines The ease is contributed to the single part being replaced with a similar part. Anyone can put the round peg in the round hole.

    This type of upgrade is a downloaded fuel map into your factory ECU (Electronic Control Unit) to improve the performance of the engine in your vehicle. These come from the manufacturers of the engine, and some aftermarket models are available. Ask the dealership where you bought your toy for more info.

    This is the simplest method for upgrading the amount of fuel input into the engine. However, as a racer, engine tuner, or hobbist; you get no control of the fuel maps.

    Piggy Back Controllers

    Piggy Back Controllers connect into the OEM (Original Equipment Manufacturer’s) wiring harness to make changes to the fuel map by changing what the vehicles computer “SEES”. These little electronic boxes receive the info form the vehicle sensors and alter that signal on the way to the computer. The effect is telling the vehicle it needs more fuel by a percentage based on temperatures……“fooling” your factory ECU into providing a different amount of fuel than the real engine conditions warrant.

    Again; you get no control of the fuel maps.Piggy Back controllers can directly or indirectly extend the time the fuel injectors are open, but you have no control over the timing and such.

    Engine Management Software

    Software packages are available for motorcycles, semi trucks, ½ ton and full size pickup truck engines systems. These software packages, patch cords, and a laptop allow you to literally tap into the computer and program it yourself. You are actually making changes the internal fuel maps for the EFI. Many software programs give you control over one or all of the following sensors; ignition, O2, temperature, and knock sensors. Complete control of the system is what we want when we are building an off road, small bore performance engine, race engine or an above average street engine for any purpose.

    With anything good comes the bad, this isn’t easy. The level of education, patience, and ingenuity necessary to “Learn” to use these software packages can be daunting. The average mechanic is unlikely to optimze their fuel maps. Many have ruined engines trying……Get trained to understand how to use these software packages.

    ECU Replacements

    There are a couple of companies that make EFI replacement ECUs. These ECU’s replace the factory EFI and provide a completely separate fuel map. Some are software compatible and have their own software to control fuel mapping, some have presets and are simple, others aren’t so much. Aftermarket ECU’s are predominantly more sophisticated than OEM ECUs. They are either more capable, more user friendly, or have the ability to expand the number of fuel injectors in the system. Many OEM units are limited in their upgrade and software capabilities so aftermarket companies have stepped up to fill the need for tuners, enthusiasts, and racers.

    Auxiliary ECU

    This is a interesting way to basically fool the fuel input signals into your engine’s fuel injectors. By simply adding a second ECU (electronic control unit) to your EFI (Electronic Fuel Injection) system, you can elongate the pulse the fuel injectors receive. This method is useful for fuel increases, but worthless for efficiency and emissions. Each fuel control unit acts independently, one factory OEM ECU and an auxiliary. Each ECU charges the wires independently, and the fuel injectors don’t care where the energy comes from.

    This system is absolutely awesome for unusual configurations. The secondary ECU can be turned on exclusively for times with NOS, or for secondary fuel rails at higher rpms with turbo and supercharger configurations. Many a racer race engine utilizes these tricks or unusual engine configurations. With a secondary ECU, one can install secondary and tertiary sets of fuel injectors in each cylinder. Each can then be controlled to compensate for situations where a lot of extra fuel is required.

    For the average home mechanic, a simple Chip Upgrade or Piggy Back Computer that plugs right into the machine is usually fair game. On the other hand race vehicles, and specialized engines builders are encouraged to be all they can be with full control of the systems. Remember Racers, you are limited by the rules of the sanctioning body. The rest of us are limited by our own engineering skills .

    Fuel Injection System Tampering Disclaimer

    Modifications to a modern engine’s electronic fuel injection system, or EFI system, are not guaranteed to produce more power, performance, or enhance operation. Modern engines are generally factory tuned using computers and very high Q&A tolerances. While proper changes to an engine can result in significant power increases, the owner of the engine or vehicle must ultimately assume responsibility for the changes made. The author does not endorse or condemn any of the modifications listed in this article, nor assumes responsibility for changes a mechanic may make to his or her vehicle/engine based on this information.

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