I need help. I have 2 12” running on 1200w amp. I have had this system for about 5 months and never had a problem until now. I can hear the engine through my subs. I looked it up on the internet and I check the ground I checked the rca cable by using a new one and I also check the fuses in the amp and all are fine. Does anyone know what to do or has anyone had this happen. I may take the whole system out tomorrow and redue it but I rather try your suggestions first. Thanks for your help

There are 2 types of "engine" noises that usually show up.
1) from ignition system
2) from alternator

Radio shack or any audio house has flters for either / both of them.

Ignition sounds like dots from the spark plugs firing. Alternator sounds usually like a whine that is rather high pitch and changes with engine revs.

It is like thumping but real fast

Oh I might add it soounds like a helicopter. It also thumps when I hit break like if I tap the break it thumps through subs but don't hear it as much when I have music on. However it don't make noise constantly when only one rca is plugged in but as soon as I plug both in it goes insane.

it is like thumping but real fast

That sounds more like feedback if just the subs are affected. If that is the case you could isolate them with a inline diode and that might help.

How much will that cost on average

Depends where you get your diodes. They run anywhere for 10 cents to a dollar each depending on where you get them.

Allright thanks I will look around for one and see what happens