Product Description
Wisher Performance Auxjection Fueling Kit - Cadillac CT5-V Blackwing LT4
Need more fueling than the LT4 DI system can support, but don’t want to rely on meth injection or invest in a full port-injection setup?
AuxJection fills the gap with a clean, factory-style solution that installs easily and integrates seamlessly with the ECU.
HOW IT WORKS
AuxJection is a fully integrated auxiliary fuel-injection solution engineered to work within your vehicle's factory ECU—no external controllers, or piggybacks required. By utilizing custom ECU software (detailed instructions provided in your kit) that gets written to the ECU, AuxJection drives additional port-style injectors with the same precision you would expect from the stock controller.
AuxJection's internal calibration logic uses real-time ECU data to calculate and deliver auxiliary injector pulse width on the fly when a user-specified duration of direct injection window is met. After installation, the vehicle tunes no differently than if it were equipped with a higher-capacity fuel system from the factory.
The included fuel line set reroutes the low-pressure feed from the DI system at the firewall, through the throttle-body assembly, and returns it to the DI system inlet—allowing the auxiliary system to share the OEM low-pressure circuit without modifying factory hard lines. The plug-and-play harness combined with the pre-made fuel lines make this kit the EASIEST installing product on the market for adding an auxiliary fuel source.
COMPATIBILITY: 2022+ Cadillac CT5-V Blackwing
FLEX-FUEL SETUP OPTIONS:
OPTION 1: I Already Have a Flex Fuel Sensor – Includes the AuxJection harness, integrated flex-fuel sensor wiring, and required fittings. Your existing flex-fuel sensor will be reused.
Note: Flex-fuel sensor must be mounted in the same location as shown in the product photo. If you already have a flex-fuel kit installed, proper fuel line fitment cannot be guaranteed, as the lines are designed for a specific routing configuration. Existing hardware may need to be removed, but your sensor can be reused.
OPTION 2: Add a Flex Fuel Sensor – Includes AuxJection harness, required fuel line fittings, and flex-fuel sensor for a complete installation.
IMPORTANT: Custom ECU software is required. You must send us your current tune file to modify. (See custom software | tune file process dropdown below) AuxJection will not function until the modified file is written to the ECU. *ECU flashing tools are not included.
WHATS INCLUDED
- Billet throttle-body flange with matching fuel rail (compatible with stock throttle body up to 103mm bore)
- (2) FID2200 Injectors - flow-matched pair
- Pre-assembled, crimped PTFE AN fuel lines with all required fittings
- Plug-and-play wiring harness
TUNE FILE PROCESS

Each AuxJection kit includes an instruction card with your Kit ID #. Use the steps below to generate your custom tune file:
- Email: AuxJection@wisherperformance.com
- Subject Line: Your VIN # _ Your KIT ID # [Example: 1G1Y82D47L5000324_#010126_01] *Include both VIN and Kit ID # to avoid delays
- Attach Your Tune File: Accepted formats: .HPT or .BIN
- Turnaround Time: Your modified file will be returned within 1-3 business days
Once your file is received: You MUST "WRITE ENTIRE" for the first flash. Failure to do so will result in the system not functioning.