OneGauge is compatible with all Fitech EFIs because, rather than using Can Bus (which is only available in newer Fitech units), OneGauge uses a splitter for the communication between the ECU and handheld.
OneGauge provides a small, “headphone style” splitter used to split the Fitech handheld’s connection to the Fitech ECU. There are two options for installing the splitter. The OneGauge hub needs to be grounded (black wire provided as one of the two main power wires) before the splitter is connected to the Fitech system. Only power on the Fitech, when connected to the OneGauge hub, when the hub is grounded or damage may occur.
- All Fitech systems have two connections coming out of the ECU/throttle body. One is a two-pin power connection, the other is a headphone style female connector. Typically, the male end of the cable for that connects to the handheld plugs in here. To install the OneGauge splitter here, insert the male end of the OneGauge splitter provided (also called a y-cable) into the female jack on the Fitech ECU/Throttle body. One wire of the y-cable will go to the ‘Fitech’ terminal on the OneGauge hub (see Section 1), and the other female port is used to provide a jack for the original Fitech handheld cable. See photos below.
The other option only works on older Fitech handhelds. Older handhelds also had a “headphone style” jack on the top of the handheld. Newer Fitech handhelds use a USB style (see pictures below) handheld connection. If you have an older handheld, you can use the splitter to split the signal where the cable comes from the Fitech ECU/throttle body in the same way as instructed above.
Once the handheld is connected using the splitter you can begin getting data from the Fitech system.
- There are currently two options for reading data from the Fitech setup. You can change these options on the Fitech Settings screen in the setup menu (see Appendix D).
- Automatic mode communicates with the Fitech ECU automatically. It is recommended to have the handheld either unplugged or unused if this setting is used. This mode will often disable the use of the handheld since both units cannot communicate with the Fitech ECU at the same time.
- Listen mode (“Fitech Comms” set to 2) requires the use of the handheld. After the Fitech system starts, push the main button one time to open the Dashboard menu and allow the Fitech handheld to start receiving data from the ECU. The handheld and the OneGauge dash will now both display data. It is important that only the “Dashboard” screen be used, however – other screens, tuning, and menus will likely send incorrect data to the OneGauge hub and give incorrect readings.
The user can also use the Fitech Settings menu to select between Standard Fitech ECUs and the Ultimate LS system, which has a different mode of communication.