FD3S Fuel Voltage Low, Resistor

[Rotary Evolution]

Originally Posted by Sharingan 19

I just did this on my FC, WOW what a difference. I used to get 8v cruising, and sometimes it would drop to 7v in boost, with a max of 10v.

I chose to keep the voltage regulator and relocate it to the rear near the pump running new wires directly from the battery to a new relay, to the regulator to the pump. I did this because I am still on the stock turbo so its not that crucial to have 12v all the time. This is also my daily so having some fuel economy would be nice as well.

Now I see 10v cruising and 13.5 wot!!!

To answer one of the original questions; I believe David Haynes (20b fd) has burnt up a pump running 12v constant, and it didn't even take that long. He was running dual pumps though, ,so I'm not sure if the additional amps played a significant role.

upgraded fuel pumps pull additional amperage, single stock fuel pumps running stock battery voltage levels may never see the connector on top of the fuel pump burn up but i do suggest doing the bulkhead connector modification when upgrading the fuel pump and/or rewiring it for higher voltage.

the FC S5's had the small 4 pin junction connector on top of the fuel tank as well as the FD and both have issues with that connector melting down when pushing too much juice through it. i have yet to see an issue with the S4 fuel pump housings. i have also had one customer who had his housing connector melt down with his walbro255 in his firebird superchicken WS6, had a similar connector to the S5/S6 tank connector styles.

bulkhead, bulkhead, bulkhead. do it in conjunction with upgrading your fuel pumps.

on the upside, the connector melting down usually won't take a motor with it but it will leave you stranded on the side of the road with a car that won't start.

anyone with a standalone should do both the rewire and bulkhead connector modification. if running the stock ECU still on an FD you can rewire the fuel pump to push better voltage through the relay by wiring the factory relay directly to the battery.