I/O pin default low.

[pescador]

Top secret electronic ignition ??? ....
MC3334P clone ?

- ADC inputs have a maximum input feed impedance to respond as fast as required ... see Pic datasheet for details.

so, I presume @ first sight your current detection is wayyyy too slow, and your coil enters saturation ...

add to that your IPB protection is wayyy too weak and slow !!! be prepared for in-use failures, after some running time.

Now, automotive circuits need lots of filtering to avoid pic supply surges ...

Alain

no - not a clone of MC3334P - it just turns on a load if IG is present.
by the time I get the IG signal its been filtered.

What coil?

IPB?

[tumbleweed]

Your ANSELA statement is incorrect... you don't set it that way.

[pescador]

Your ANSELA statement is incorrect... you don't set it that way.

ok - please elaborate..

[tumbleweed]

ANSELA is an 8-bit register... you set it just like any register, 0-255

If you want RA2 to be analog but all others digital then ANSELA = %00000100

You have something very different... ANSELA = PORTA.2, which will read the value of the port pin and assign it to ANSELA (whatever that results in).