Engine Noise through Speakers

[Carbon_z]

Well I did a bunch of searches and assuming i have to ground my RCA's but want to verify. The first Head unit I had was a Sony xav70bt. It didnt produced any engine noise. The ground wire, amp, speakers etc are all still in the same place. The new replacement headunit is a Pioneer Avic-x920bt. Only difference setup wise is that a bypass was done on the harness of the new unit for dvd and nav usage. Once the unit is turned on, the pioneer produces alot of engine noise through the speakers. The second the unit is powered up the noise is NON STOP. If I turn the car ON but without cranking it, the noise only appears when the car is in gear but if in neutral the engine sound does not come through the speakers "WEIRD". . When car is cranked on or turned over, engine sound comes through speakers whether in gear or neutral, unlike the on position did in my previous sentence. I ran the power wire down the passenger side, amp is located behind the passenger seat. Ground wire is bolted on one of the passengar seats bolts. I have a 3 channel amp and have tried replacing the RCA's with another pair and the same sound occurs. I figured replacing the RCA would fix it but i tested the NEW RCA's without tucking them in, just loose away from everything but the sound was still there

Any help would be great.