EFI fuel pressure ?

[supremeefi]

Originally Posted by camcojb

that's not entirely true............ Do you tune a car just enough to get it so closed loop can add or subtract and keep the desired a/f? Or do you tune it so the add/subtract from the O2's is minimal when in closed loop? Bottom line, bumping pressure from 43.5 to 58 psi is going to richen the a/f, and should be accompanied with a tuning change. My humble opinion anyway..........

Jody

I tune it for minimal correction so if you bump the pressure and the O2 is correcting it'll correct right back to the preprogrammed air/fuel, period.

If it's tuned to where the O2 has a big correction to begin with then yes it will fatten it, only because the O2 runs out of room so to speak.