I'm trying to use the PBP Count function with a bit more stability than the 16F690's internal RC oscillator provides.

My problem is that I have the crystal oscillator running with the following edit to 16f690.inc file:
; __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _MCLRE_ON & _CP_OFF ------- original code
__config _HS_OSC & _WDT_ON & _MCLRE_ON & _CP_OFF --------my edit

BUT it matters not if I remove or short the crystal, the code still runs!
I've checked the 4 MHz crystal's pins with a scope & counter and it is active at about 3999990 Hz, close enough to 4 MHz for me.
MCLR is pulled high with a 4.7k Ohm resistor.

What else do I have to do to enable the crystal oscillator internal to the PIC ?
thanks
Bob