OrionThade
Member
The 5521 and 5068 use 2 differen cam and plunger arrangements. The 5068 outputs slightly more fuel, but it does it in a quite a bit different way than the 5521 does. To swap pumps you have to swap to the correct programming to match the cam and plunger arrangement in order for it to regulate the fuel delivery correctly.
That's what I thought. I guess my question is whether a tune written for a '95 would work? Do I need to get a whole EEPROM? I would think they were the same physical chip, just different tunes. I think that's essentially what you're saying, right Ferm?