Engine noise from stereo...anybody have a solution?

[porsche_virus]

I have an aftermarket Pioneer cd player with AUX input for my DVD system. Two Punch 300's in the trunk, grounded to rear of trunk. I have just re-wired the RCA's for a second time, using a different brand than before, and running them right down the center of the car instead of along the door jams as before. My engine noise is a lot worse now. I've disconnected the DVD system completely, and the noise persists. Is there a special place to ground the deck or the amps that will eliminate this? The noise wasn't as bad when I had a Sony XPLOD deck in the car, but I'm seriously doubting that the Pioneer deck is bad. When I hook up the Pioneer deck straight to the speakers with it's whopping 25watts of power, there is little, if any engine noise. I've been installing custom audio systems for 10 years and never had this kind of problem in any vehicle, but this is my first BMW. I guess it's possible one of my Punch amps has a bad circuit, but of the hundreds of Rockford amps I've installed over the years, I've yet to come across a bad one (except when running 8 speakers in parallel at 1/2ohm on a Punch 45 in the 1980's during Summer).

[RRysedorph]

You can always get a "Pyramid" noise eleminator for the RCA cables. You can also do one for the Power cable, but it's usually a 18ga or higher cable so it makes it hard to attach that to 4ga wire on your amp.
While this will lower some of your amps performance, it's about the only thing you can do. Most likely the problem is in your amp. If it's out of warrranty, take the cover off and check the solder on the large capacitors, those are usually your noise eliminators. Just wiggle them back and forth to test. It's rarely where you have your RCA cables running anymore, they just make them better now.


'92 325i
RRysedorph@aol.com

[Jared at Pelican Parts]

Better grounding...

Run a heavy gauge ground from your amp to the body.

[trknox]

I know, sounds stupid but... If it's worse on AM, change the plug wires. Worked like a charm on my old SE-R

[matthew-m]

I believe the problem will be solved if you avoid the computers under the dash. I haven't had a chance to definitively test this theory. A while ago I swapped cables, but I just quickly threw them over the interior, straight out from the radio. Engine noise was gone but it was ugly. You can also try grounding directly to the battery since it is in the trunk anyway. Good luck in your search.

[Jared at Pelican Parts]

That is exactly what you want to do. Better grounding will solve the problem.