I don't think i ever programmed the chip with EA being tied to gnd. I let it float(not good i know).
1) it is !EA (NOT external access) tie it to Vcc if you use internal code memory.
2) if you use external memory your program will excite !RD and !WR p3.6 and p3.7 and really screw it up.
3) if int0 or int1 is enabled your program will generate interrupts galore
4) just to avoid all this why not use P1 instead of P3.

Erik