TEPHRA V3 FLEX FUEL SUPPORT
Introduction
Since Flex Fuel is the major feature addition to V3 this document will focus on exactly how to utilise it.
The V3 implementation is a little different to other implementations out there, for starters we have different interpolators for the different maps sets, which allows the tuner to set up the car perfectly. Additionally, and perhaps more importantly, the ECU averages the ECA signal over a time period. This means that the ECU doesn’t automatically trust the sensor output, and any changes will be slowly averaged over time. This also means we can alert the driver (by a Check Engine Light) that there is some inconsitancy between the Sensor and ECU, which allows the driver to take action.
Step 1 – Electical connection of your ECA
V3’s Flex Fuel implementation relies on a Ethanal Content Analsyer to accurately measure the Ethanal % in your fuel and then store this information in the ECU. Any sensor that outputs a 0-5v analog signal for ethanol content can be utilised, however Zeitronix ECA2 and FuelConvertor.com’s units have been tested sucesfully to date!
You will then need to connect the 5v analog output of the sensor to the ECU, at the moment we are hooking into the only “available” 5v input left on the ECU, this happens to be currently being used by the Fuel Tank Pressure sensor, which feeds into EVAP. Since we are overriding the pressure signal for flexfuel we send a fake signal to the EVAP system so that it doesn’t complain. Using the diagrams below connect the 5v output from the ECA to the ECU
The Fuel Tank Differential Pressure Sensor ECU Input is PIN 112, it’s worth noting that USDM is different from AUDM or EDM, the diagrams below will work for USDM, however for AUDM or EDM you will be required to install a pin into the ECU Wiring harness:
Note – that the cable colour is shown as brown below, however for later model cars it appears to be blue
You can tap into this in various places, but the “best” would be up near the dash; You should see the C47 conenctor on the left, and that runs straight down and into the tunnel that runs up the left side of the car:
