RxRolla

iTrader: (1)

I feel like I knew how to do this years ago but now I can't figure it out. I need to cut power to fuel pump for tuning purposes so that the pump doesn't build a bunch of pressure on lines while car is off but with ignition on. I know I can take off the engine fuse and that cuts power to it but then I can't tune properly. How can I do this without just disconnecting the pump? Any ideas? Thanks

j9fd3s

iTrader: (3)

i unplug the circuit opening relay, on an LHD car its right above the drivers right knee, so you can reach it from the drivers seat.

spectre6000

iTrader: (1)

I actually have a switch on mine. The weather and my work schedule are not conducive to taking photos of it right now, but maybe tomorrow if you can wait.

RxRolla

iTrader: (1)

Thanks guys Ill look into the relay today. Ive thought about just putting a switch for this I just hate messing with electrical stuff on this car.

misterstyx69

iTrader: (142)

another thing you can do is disconnect the fuel pump at the pump.
the connector is a little hard to get at but it will work for what you want to do.

Aaron Cake

iTrader: (1)

Why do you need to cut power to the pump for tuning purposes? Not build a bunch of pressure? Unless you have some weird rail setup, the fuel pressure is set by the regulator.

Or unless perhaps you have WAY to much fuel pump for a carburetor and the wrong regulator?

Also the fuel pump should NOT run with the car powered up unless the engine is running. Any EFI system will have a fuel pump output that cuts if the ECU doesn't see RPM.

If you have some sort of carb conversion, then it's a different story. But in that case the fuel pump should be relay controlled with a rollover switch anyway, so just trip the switch or disconnect the relay.