On a stock tune, what conditions need to be met for the high speed fuel pump relay to activate?

 

When I was wiring my swap I thought I read that the high speed was used when the car was running, low speed is used when cranking. I know you're trying to make your swap ridiculously complete and all, but for your engine's normal application, does the fuel pump have variable speed? The only detriment I can think of with always using the high speed is that there will be a small amount of pressure built up until the engine gets running and needs the full speed, but you could always put in an inline pressure regulator, which would probably be a better solution than running too lean when cranking. I've had no issues running my 5.3 swap just bypassing the low speed.

Good luck.

 

I'm adding a return line, in-line filter, Aeromotive regulator, and high volume pump. The in-tank filter and regulator will be bypassed. I plan on running my return line to the jet-pump. My concern is if the jet-pump's pop-off valve will flow enough volume not to cause a rise in pressure.

If it's anything more then RPM triggered, I probably won't be able to use the 2-speed option. The original application used a single speed pump.

 

If it was me doing it...I would wire the fuel pump to a relay straight off the battery and use the OEM wire as the relay trigger

 

I haven't seen the pump wiring so I couldn't say what gauge it is. I know that's common to run another wire and a relay when a larger pump is used. I don't know what aftermarket pumps fit the S1 housing either. Haven't had time to read through the fuel pump thread yet.