Sorry to necromance this thread, but thought it was relevant over just opening another one. How can the re-wire make you go rich unless you are outflowing your pump? (I do realize that was the caveat you put in so maybe that's the answer). As long as you have good pressure and are under the flow limits of the pump, the ECU and injectors should be the ones taking care of the mixture, not the pump? Or is there a piece I'm missing?
For example, if I have an AEM 340lph and I've estimated my peak fuel needs to be about 181lph (ID1000s at about 74% IDC on e85 targeting 11.6AFR, 21psig in Denver, 17psig compared to sealevel and 12psig at redline compared to sealevel), re-wiring shouldn't affect my tune if I have good base pressure and my pressure is rising 1:1 with boost right? Even if my pump were flowing less due to the factory wiring, I should still have plenty of fuel as long as pressure is behaving as it should?
It can't -if your fuel pressure is correct and not falling below the regulator pressure, it won't change anything.
If your fuel pump (for whatever reason) can't keep up with the flow and pressure demands - generally at high load/rpm, fuel pressure will drop, and IDC would have been increased to compensate. Unless you're watching fuel pressure live as you do this, you don't know (but you could probably calculate it).
Obviously if you fix the fuel pressure/flow issue, your IDC is now increased vs what it should be, and you will run rich.
Upgrading Your Fuel Pump Wiring (4th Gen)
in Walkthroughs :: Performance Modifications
Posted
It can't -if your fuel pressure is correct and not falling below the regulator pressure, it won't change anything.
If your fuel pump (for whatever reason) can't keep up with the flow and pressure demands - generally at high load/rpm, fuel pressure will drop, and IDC would have been increased to compensate. Unless you're watching fuel pressure live as you do this, you don't know (but you could probably calculate it).
Obviously if you fix the fuel pressure/flow issue, your IDC is now increased vs what it should be, and you will run rich.
I've just done this modification myself: