Here is a little background: I have an EvoIX that I just started yesterday with the series 1 EMS. I’m using a full blown twin pump hanger with the second pump controlled by a Hobbs switch. Now that I have an EMS I could use an available output to control the second pump, but it already is working fine. I’m using the factory wiring on the primary pump, from my understanding this pump is speed controlled when configured with the factory ECU.

Where does this control speed exist, in the ECU or another module? The pump must be running slow since my idle fuel pressure is controllable. My only concern is to make sure the pump exits the “Slow” mode and enters “Fast” mode with the AEM EMS. I didn’t want to wire it to a direct source in avoidance of uncontrollable fuel pressure at idle, makes for easier tuning.

 

Pm mr fred is my best guess

 

the base map that comes with the S1 aem doesn't use the fuel pump speed output. So unless you enabled it, it's not on.

You can check how it's setup in your tune by looking at the low side 4 output in the configure outputs screen.

(activating LS4 output will put it in "slow" mode)