REV2 Board: Secondary Fuel Pump Wiring and Calibration in Map Editor (Port Injection) - bootmod3 CustomROM V2
Overview
REV2 Board provides a a pulsed ground output for the secondary fuel pump which can be used with brushless or brushed fuel pump controllers.
WARNING: Pulsing standard (non-solid state) automotive relays is not recommended as it shortens their lifespan. If you’re using a standard automotive relay, which is most often used out there, and you hear your relay buzzing (pulsing) while driving/idle/ignition on, make sure to adjust your fuel pump calibration.
When used with a standard automotive relay and a standard brushed pump (e.g. Walbro 450/520, etc), the Fuel Pump duty cycle should be set to 100% in areas where the pump should turn on with minimal to no interpolated scaling so the table setup virtually acts as a toggle switch from OFF to ON to the relay instead of it being pulsed.
We strongly recommend having the OEM DI fuel lines fully separated from the PI fuel lines as described below.
Ideal fuel feed/pump setup for secondary port injection is the following:
Fuel lines for DI left dedicated to the DI side of the fuel system.
Adding a Y-split on the DI fuel system and cranking up the LPFP fuel pressure is often used out there but is
In-tank secondary fuel pump(s) having a separate feed (possibly through a surge tank) with a return line back to the tank (or surge tank) that is regulated through a Fuel Pressure Regulator (FPR) with a vacuum line from the intake manifold to the FPR for a 1-to-1 rise in fuel pressure with the rise in intake manifold (boost) pressure providing a constant/regulated differential fuel pressure at the secondary fuel injectors.
Secondary Fuel Pump Installation - Connecting with REV2 Board
REV2 Board provides a ground output for the automotive relay that triggers the fuel pump, see diagram below. Red is 12v, yellow is the pulsed ground output from REV2.
WARNING: Fuel pump must not be directly wired to the REV2 Board. Fuel pump needs be wired to the battery and chassis ground for triggered through an automotive relay as outlined above.
Failing to wire the pump correctly may cause fuse blowout in the bulk connector on the REV2 harness that houses a relay and fuses inside.
Secondary (AUX) Fuel Pump Table
To activate the LPFP fuel pump output, use the following Aux Fuel Pump Activation table.
To control the pump the following, the following table is available to set up fuel pump duty cycle based on Intake Manifold Pressure vs. Engine RPM. DME sends the desired duty cycle over FlexRay to the REV2 board which in turn pulses the LPFP output.
While the LPFP output can be set up for any duty cycle 0-100%, for brushed style fuel pumps that are activated through a standard automotive relay, we don’t recommend pulsing them as discussed in the warning at the beginning of this document. If using a brushless setup, the LPFP output can be connected to the brushless fuel pump controller’s PWM input to regulate fuel pump flow.