FAST EZ-EFI, Fuel Pump Control and ISIS...

We had a customer just ask a question on our website about integrating the Fuel Air Spark Technology (FAST) EZ-EFI system. He wanted to know how to control his in-tank fuel pump with our ISIS Intelligent Multiplex System and the EZ-EFI system.

If you look at the instructions that FAST gives you for the EZ-EFI™ Self Tuning Fuel Injection System, they detail the connections to their EFI wiring harness. There is a wire in their harness labeled "Fuel Pump Relay". This is designed to ground the coils of the fuel pump relay. Here is the diagram from the FAST manual.

You can download their entire manual here.

You connect the fuel pump input on the MASTERCELL directly to this wire on the EFI controller. In the ISIS standard front-engine configuration, this is input 19 which is the Tan-Yellow input wire. Essentially, you are replacing the fuel pump relay with ISIS.

When the EFI controller wants the fuel pump to turn on, it closes the "Fan Pump Relay" circuit to ground. This grounds the input to the MASTERCELL, which sends a command to the rear POWERCELL to turn on output 10, which energizes the fuel pump. There is no need to run any additional wire to the back of the car from the EFI controller. This command is carried through the ISIS CAN cable from the MASTERCELL to the rear POWERCELL.

Check out our reference library to get other tips and tricks on how to simplify wiring your car at www.isispower.com.