| Yeah the dual pressure thing is ECU controlled as I've looked at it for the VEMS RB25 harness adaptor, I was told by a highly respected Skyline tuning company to not bother trying to control it because they often don't work, and the cars run fine without them.
I think its there to lower fuel pressure for low RPM emissions purposes (less fuel pressure = longer injector opening times which means more control resolution).
You should be able to use the standard fuel relay control wire, to pin 86 on James' diagram. |