More Fuelish Pleasures

1. FiTech provides everything you need to convert to electronic fuel injection in one box—and it’s not much more complicated than installing a carburetor.

By Ron Ceridono Photography by THE AUTHOR

lthough the hobby we all know and love is steeped in tradition, hot rodding has always embraced technology. Early examples include aluminum heads for Flathead Fords; today, it’s electronic fuel injection systems like those offered by FiTech.

We cannot often conduct long-term testing on hot rod components, but we’ve accumulated nearly 50,000 trouble-free miles using a FiTech throttle body system. So, when it was time to select an induction system for a new project, we again chose the same system we used earlier: a Go EFI 4 600hp system. Although this system is rated for up to 600 hp, it is appropriate for engines producing 200 hp and above.

As often happens, FiTech has refined its products over the years, so we decided to check out the changes that have been made. From a functional standpoint, FiTech got it right from the beginning; the new systems are still self-tuning, and installation remains simple. After basic engine information is entered into the handheld controller, it establishes parameters for air/fuel ratios at idle, cruise, and wide-open throttle. In simple terms, the self-learning function involves the electronic control unit (ECU) using feedback from various sensors to adjust and maintain the air/fuel mixture under all conditions.

Manifold Absolute Pressure (MAP) for altitude compensation and load correction

Coolant Sensor (CTS) monitors operating temperature for fuel adjustments (think of it as the choke)

Throttle Position Sensor (TPS) feedback for fuel control

Idle Air Control (IAC) bypasses air to maintain a consistent idle speed

Inlet Air Temp (IAT) compensates for changes in air density due to air temperature

The Oxygen Sensor monitors the amount of oxygen in the exhaust to indicate how rich or lean the fuel mixture is

Besides the oxygen sensor and CTS, all other sensors are housed in the throttle body

Although there are minor differences in the throttle bodies (as noted in the captions), the installation procedure remains the same, as do the mechanical requirements. The engine must be in good condition; EFI won’t cure mechanical shortcomings. The exhaust system must be free from leaks, as these will disrupt the oxygen sensor’s readings, leading to improper air/fuel ratios. Likewise, intake manifold leaks create similar problems. The charging system must be capable of maintaining the correct battery voltage and the system must be properly grounded. Another consideration is the ignition system. Point-controlled systems and Mopar electronic ignitions with the typical rectangular controller and dual-element ballast resistor will not provide the correct tach signal to the FiTech ECU. However, FiTech now offers a line of replacement distributors that solve both problems.

Due to FiTech’s refinements over the years, there are four versions of ECUs and handheld devices. However, rather than making previous systems obsolete, FiTech offers updated software that can be easily installed in the handheld controller via a home computer.

To make software system updates, the original version of the system must be identified. This is done through the configuration of the handheld display. The older, smaller handhelds may have nothing around the joystick, while the later, larger handhelds may have four triangles on the right edge or may feature a plain surface with two dots. Once the handheld is identified, FiTech can supply the appropriate software updates, which is critical. Loading the wrong software into the handheld can permanently damage it, void the warranty, and require the purchase of a replacement.

Once the handheld is identified, a FiTech representative will provide the appropriate updated software file. After downloading the update to a desktop computer, the handheld is connected to the computer. Following the instructions on the computer screen, the original software is removed from the handheld, and the new version can be installed. Once the handheld is reinstalled, the ECU in the throttle body will operate on the new system. (FiTech has a complete video showing the update process.)

In subsequent installments of Modern Rodding, we will present more “fuelish pleasures,” such as the complete bumper-to-bumper procedure for installing a FiTech fuel injection system, along with tips on tuning, maintenance, troubleshooting, and additional information.

3. One of the changes made is the location of the secondary throttle stop; in the early design, it was located on the right rear side of the throttle body (arrow).

4. On the late-style throttle body, the secondary throttle stop is positioned on the left rear side (indicated by the arrow), making it easier to access.

5. Here, the difference in thickness of the mounting flanges can be seen; the new version on the right is slightly thicker.

7. In comparison, this is the idle bypass in earlier throttle bodies (arrow). On large displacement engines, the smaller bypass required the throttle valves to be opened further at idle.

9. A noticeable change has occurred in the handheld displays; the earlier versions featured small screens.

10. The new handheld screens are larger and easier to read; however, their function remains the same as that of the earlier design.

12. Electronic fuel injectors are rated by the pounds of fuel they flow per hour. FiTech fuel injectors have 36-, 55-, 62-, and 80-lb/hr ratings.

14. At the back of the throttle body is the IAC, which adjusts engine speed by moving its plunger in and out of the idle air passage as needed.

16. This is the CTS, which monitors operating temperature for fuel and spark adjustments. It is one of only two FiTech sensors not mounted to the throttle body; the other is the oxygen sensor.

18. For software updates, FiTech will provide the necessary downloads for a home computer.