Preparing for Flex Fuel Tuning: What You Need

Before configuring MG Flasher's advanced flex fuel functionality, ensure your vehicle's hardware and software are capable of handling ethanol-based tuning. Proper preparation is critical to achieving both performance and reliability.

Hardware Recommendations

Ethanol Content Analyzer (ECA)

Required for fully automatic blending. Its possible to manually set ethanol content by the driver to still allow blending for fixed ethanol values if an ECA is not installed or malfunctioning.

Network: The ECA must be wired to the PT-CAN2 network for proper communication with the DME.

CAN ID Configuration: The ECA’s CAN bus ID must be specified in the MG Flasher app during setup.

Supported Hardware: Commonly supported ECAs include Motiv Reflex (with a Genuine Continental VDO ethanol sensor), Zeitronix, and Fuel-It. However, any CAN based ECA can be used if it utilizes a supported CAN ID (set in app) and follows the same data layout as Zeitronix’s ECA.

High-Pressure Fuel Pump (HPFP)

Recommendation: While stock HPFPs may suffice for ethanol blends up to E30, upgrading is highly recommended for blends over E30, especially on Gen 1 B58 engines.

Optimal Blend: MG Flasher suggests tuning for E50 for the best balance of performance and fuel system efficiency. Ethanol blends above E50 yield minimal performance gains while increasing fuel demands.

For full E85: Upgrades such as the Dorch Stage 2 HPFP or FX-180 HPFP are strongly advised.

Low-Pressure Fuel Pump (LPFP)

E50+ ethanol blends: Although not always necessary, upgrading the LPFP is recommended for setups with E50+ ethanol blends to avoid fuel starvation under high load.
Pressure Sensor: We recommend using Motiv’s Reflex or Fuel-It with a low pressure fuel pressure sensor to monitor the LPFP. Since Custom Code v7.2, this sensor can be used to trigger limp mode and protect the engine from fuel starvation.

Software Recommendations

Custom Code v7.3

MG Flasher's Custom Code v7.3 or later is required to enable flex fuel logic. Verify compatibility with your ECU here: Custom Code Supported ECU Software Versions

Customized Stock Map

Our code runs map validity checks when the DME boots up. This verifies the mapping data has been populated and there is no null data (0x00, 0xFF, or 0xC3 filled maps) to ensure the engine operates smoothly. If the maps fail to verify, map switching and/or flex fuel blending will be automatically disabled. We have introduced loggable parameters to see which map slots are valid.

You can save time from copying stock map data to each map slot or flex fuel slot by utilizing the built in-app tools. Stock map binary files can be generated from the Custom Flash page when you selected with Custom Code v7.3.

Flex Fuel Blending Enablement

The binary file (custom tune) must have the minimum tables populated (describe here: Available Tables/Maps for Tuning). Per slot ethanol content override and other codewords may be set either in-app or in the tune (“Override Custom Code tables with binary” option needs to be selected while flashing to read codewords from file). Note, this override applies to all codewords, not just those related to flex fuel. Reference our map packs for a full list of codewords.

Flex Fuel can be activated using the following:

Automatic Mode (ECA Required) → Real-time ethanol adjustments.

Static Mode (ECA Not Installed) → Define a fixed ethanol value.

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