06 Mercury Milan Amp Turn On Pop

I,ve got an 06 Mercury Milan. After installing a Double Din Pioneer unit, I get a turn on pop when I turn on the ignition through the rear deck speakers which are the factory subs which are on a dedicated factory amp. The speakers in the front and rear doors make no pop...only the rear deck speakers. Everything is stock except the head unit. Any suggestions?

The factory amp is turning on before your HU.

The factory turn on lead runs on 5 volts, not 12. You need to put a 1.5K ohm resistor inline on the turn on lead.My ex once told me I have a perfect face for radio.