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The Basics Of Fuel Injection With EZ-EFI

While the idea of making the switch to fuel injection may seem daunting, in actuality recent advancements in technology have made the conversion process easier than ever. An EFI system will provide any vehicle with a much more efficient method of delivering fuel to your engine than can be found with a carburetor.

Whereas a carburetor relies on suction created by intake air rushing through a venturi to draw the fuel into the airstream, fuel injection atomizes and forcibly pumps the fuel through a small nozzle under high pressure and shoots just the right amount into the engine. This allows the user to have more control over how much fuel is delivered for a variety of scenarios, such as when traversing steep hills or driving in rough weather conditions, and also provides a noticeable increase in fuel mileage and efficiency.

Just as its name implies, the FAST™ EZ-EFI system provides an easy way for users to take advantage of the benefits of electronic fuel injection, even if they have no tuning experience. The EZ-EFI is made up of several main components: the throttle body, an Engine Control Unit (ECU), a wiring harness and a hand-held user interface. If the user is swapping out his carburetor for an EFI system, the EZ-EFI bolts onto any carbureted manifold and works with the original carb-style throttle linkage. Users simply need to hook up the necessary clearly labeled wires, answer the basic Setup Wizard questions about their engine on the included hand-held display and the system tunes itself. Here, we will take a look at how the EZ-EFI makes fuel injection so easy.

The EZ-EFI throttle body takes the place of the carburetor by bolting on to any intake manifold with a 4150 square flange. The throttle body is a metal plate that allows varying amounts of air into the engine. It is flanked by fuel rails on which four or eight injectors are mounted, dependent upon vehicle make and engine type. While Precision-Flow™ Injectors come with the EZ-EFI, OEM injectors may also be used. Just as with a carburetor, the more pressure that the user applies to the accelerator, the more the throttle body will open to allow air into the engine. However, in an electronic fuel injection setup such as the EZ-EFI, the position of the throttle blades is measured by a Throttle Position Sensor (TPS) and the measurement is sent to the ECU. The ECU then increases or decreases the amount of fuel being sent to the fuel injectors to obtain the desired air-fuel ratio. Unlike a carburetor, an ECU can compensate for a variety of driving conditions, such as humidity, temperature changes and inclines. The ECU can be mounted either in the engine compartment or in the interior of the vehicle itself.

In addition to the TPS, other sensors include the Idle AIR Motor (IAC), Manifold Absolute Pressure (MAP) Intake Air Temp (IAT), and Coolant Temp Sensor (CTS). These sensors, with the exception of the CTS, are located in the throttle body and work in unison to provide the ideal fuel setup. The Idle Air Motor is controlled by the ECU and adjusts the idle speed to what you would like it set at. It lets a measured amount of air bypass the throttle plate and into the engine at idle, and makes the idle speed consistent whether the ambient air is hot or cold. The MAP sensor alerts the ECU as to the load on the engine when accelerating, decelerating or cruising. It does this by watching the amount of vacuum in the intake manifold. Under heavy load, such as when accelerating, this sensor will make the fuel mixture slightly richer in order to allow the engine to produce more power. Conversely, during deceleration or cruising, the mixture will be leaner to reduce fuel consumption. Meanwhile, the Air Temp and Coolant Temp sensors tell the ECU what environment the engine is in (i.e. whether it is running hot or cold) and corrects any deficiencies. If the engine is running cold the injectors will stay open longer to let more fuel into the engine, while they will close sooner to let in less fuel if a hot environment is detected.

Finally, a wide-band O2 sensor, mounted in the exhaust system, samples the exiting exhaust gas of the engine (air/fuel mixture) and compares it to the commanded Air/Fuel Mixture Target in the ECU. It determines if the engine is running too rich or too lean and makes adjustments accordingly. In essence the O2 sensor then is responsible for making the final calculations within the EZI-EFI setup.

The EZ-EFI is also ready to accept all OEM sensors, including standard GM versions available at any auto parts store. It does not require proprietary sensors that are only available from the system’s manufacturer. Therefore if one sensor goes out the user can quickly and cheaply replace it, a luxury not available with other EFI systems.

Engine speed is a fundamental element of fueling calculations as well. In order for the EZ-EFI<span style=”font-size: 0.65em; font-weight: bold; vertical-align: text-top;”>&reg;</span> to operate properly, it relies on the ignition system for a steady RPM signal. This can be accomplished either through an aftermarket capacitive discharge system, or through an inductive coil. For the inductive coil option, the included RPM module is required.

The EZ-EFI also features a variety of other options and add-ons. A second throttle body as part of a Dual Quad Upgrade Kit is available, capable of supporting 1200+ horsepower engines and allowing for double the fuel capacity. Meanwhile, the Master Kit with an in-tank fuel pump system is self-cooled by the fuel in the tank for a more reliable and longer service life. The EZ-EFI Multiport Retro-Fit Kit is offered to bring all the benefits of the EZ-EFI system to existing factory or aftermarket equipped multi-port fuel injected engines – including GM’s TPI and LS-based engines and Ford Mod motors including the newest 5.0s. Jeep kits are available with both inline and in-tank fuel pumps to work with the unique engine requirements of older 6-cylinder Jeep applications.

Finally, a sister product, the EZ-TCU™ (Transmission Control Unit) featuring self-diagnostics, is capable of real-time switchable shift calibrations, which allows for multiple setups. This is particularly beneficial to racers, as it allows them to run one calibration on the way to the track, and then with the push of a button, have a more aggressive setup ready for the race. Compatible with most popular GM transmissions, as well as the TCI 6x Six-Speed™ Transmission, the EZ-TCU™ allows for maximum electronic control over shift points, shift firmness and shift speed. Packages featuring both the EZ-EFI and EZ-TCU™ are available for total vehicle control.