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lt1_fd3s · 03-17-2011, 11:13 AM

To bring this thread back to life and provide more information that i've discovered while looking into FD wiring..

The Fuel Pump Relay is used to force 12v to the fuel pump (by passing the Circuit opening relay and fuel pump resistor). From my research, this happens in hi-boost. The Circuit Opening Relay is for sending power to the fuel pump through the Fuel pump resistor...

The EGI main from the wiring diagrams appears to send power to the ECU. The Circuit Opening Relay gets a signal from the ECU to send power to the fuel pump through the previously mentioned Fuel Pump resistor...

So... to prevent the fuel pump from engaging during start up, pulling the Circuit Opening Relay might be sufficient... if the ECU doesn't send a signal to the Fuel pump relay to build pressure... so maybe pull both relays... or EGI main...

03-17-2011, 11:13 AM	#9
lt1_fd3s WNC Tour Guide Join Date: Feb 2008 Location: WNC Posts: 780 Rep Power: 18	To bring this thread back to life and provide more information that i've discovered while looking into FD wiring.. The Fuel Pump Relay is used to force 12v to the fuel pump (by passing the Circuit opening relay and fuel pump resistor). From my research, this happens in hi-boost. The Circuit Opening Relay is for sending power to the fuel pump through the Fuel pump resistor... The EGI main from the wiring diagrams appears to send power to the ECU. The Circuit Opening Relay gets a signal from the ECU to send power to the fuel pump through the previously mentioned Fuel Pump resistor... So... to prevent the fuel pump from engaging during start up, pulling the Circuit Opening Relay might be sufficient... if the ECU doesn't send a signal to the Fuel pump relay to build pressure... so maybe pull both relays... or EGI main... __________________ WNC Tour Guide - Including the Tail of the Dragon - PM for details Last edited by lt1_fd3s; 03-17-2011 at 11:15 AM.