I am having trouble getting rid of engine noise (engine whine that follows RPM). I have searched everything on the internet....here is where I am at.
C5 Corvette 1998
Installed Pioneer AVIC D2 with MTX 4 channel amp, MTX 2 channel amp for the sub. Battery is in back of car. 8 gauge amp power and ground(to chassis). does not contact or come near any other wires. Head unit is getting constant power and switched power from the plug in the passenger side kick panel. Ground is attached to the dash metal housing next to the ignition switch (key).

Here is what I have found.....When I disconnect the RCA plugs from the amp all noise goes away. When I re-attach the RCAs and disconnect them from the head unit I still get engine whine (seems as though I am getting interference in the RCA. SO...I took seperate RCA cables and ran them to the amp (basically suspended in the air)...as a test. The engine noise is 75% better but still present. When I un-hook the RCAs from the head unit and leave them connected to the amp (still suspended in the air) I still have some noise (still 75 % better)....so I have determined the problem lies in RCA interference..but from where?????

What suggestions do you guys have........why am I still getting noise when the RCAs are suspended in the air and only connected to the amp...??

I know my options are grounding the RCAs, Ground loop interupters. What are my other options..

Problem is not main grounds,.......keep in mind I am getting noise with the RCAs plugged into the amp only and not near anything (held in the air)

Any help is appreciated...thanks

Tom Ulrich

 

its definitly a grounding issue like you said. make sure you ran your rcas away from the power cables. also try changing your radio ground. this may be causing an issue.

 

i haven't read through this post :-) but it's a sticky over at mp3car.com
http://www.mp3car.com/vbulletin/showthread.php?t=79248

it should go through and show you how to isolate your problem

 

I DONT think it is a ground issue.....My thread focuses on the RCA issue....my ground is perfect...I get the noise without the head unit hooked up...so re-grounding the head unit will have no effect on the noise

Thanks Tom

 

i'm not sure i'm sold that it isn't a grounding issue on the head unit or amp. it seems like it's trying to find a ground through the rca's. i could have sworn that was an issue with; at least, some pioneer decks but it could extend to other equipment. try hooking up an ipod or portable device (isolated from the car's electrical system) to the amp and report back to us

 

I just hooked up a disc player............no engine noise. But if I touch the rca plug with my hand....I get noise.

I feel it is coming from the RCA

But.............it must be picking it up from the air...as I only have the RCA plugged into the Amp and suspended in ther air

Any suggestions?

Tom

 

how close are your crossovers to the rcas and power wire?

 

Where is the main ground at? You list it just to chassis, does this mean seat post, or back to the battery itself, or ?

For the power you are pushing your wire gauge is a touch low IMO, I would try adding a 4 gauge ground (and leaving your existing 8 guage if you want) to see if it helps with the noise issue at all. I have personally never done a battery in the back install, but I am wondering what gauge wire you have running back to the alternator as well. Are you using distribution blocks? Are all components grounded at the same location?

Most engine "whine" is usually associated with ground issues, IE poor grounds, multiple grounds, wire that is too small for the power draw, RCA's ran too close to existing power wires in the car, near crossovers, etc. As was mentioned it sounds like the RCA's are trying to become the ground.

Now another thing to consider, and this is just a guess, but if you have the battery at the back of the car I am guessing that you car is not exactly "stock" in the power department. You may be getting some interference from your ignition components (IE wires possibly).


I am not sure you mentioned what type of RCA's you are running, but the Dayton's that I got from PE are solid for the money, as are of course Knukonceptz wires. Worth the $20-25 or so.

Last thing I would check being that you were noise free with an outside source is to find a new location, or use the factory wiring for your HU ground.

IMO check these 3 things:

HU ground (patch into the factory wiring)
Increase the size of your wire for your ground, and if this does not work change the location while maintaining 1 ground point.
Replace the RCA's with a better/different set.

Fej

 

In my C6 install I used the factory ground for the head (stock NAV head) and a chassis ground for the amp and wound up with a ground loop as you're experiencing. I ran a new ground wire from the head and hooked it to the same ground connection as the amp - problem solved. Multiple grounds is one of the most common ground loop sources.

 

i agree i feel that either A you dont have a solid amp ground or B your gains are way to high

 

USED GROUND LOOP ISOLATORS.....ALL NOISE IS GONE...

aNYONE SEE A PROBLEM WITH THIS?...i KNOW IT IS A BANDAID...BUT NO NOISE!!

tOM..THANKS FOR ALL THE HELP

 

nothing wrong with it it bascially just tells u it was a ground loop you had but its not hurting anything to have it in there

 

I may have jumped the gun. I still have noise....but better.

Here is what I did today......4 gauge groung to the battery. Grounded the HU to the battery also. I noticed when I put the ground loop isolators near the air bag unit in the dash that I got engine whine.

So I moved the isolators away from the air bag unit.....noise is mostly gone...BUT when my cooloing fans turn on I get noise again.

I DONT think it is grounds....I am straight to the battery for a ground...still seems to be picking up noise through the RCAs.(which are not near anything)

very frustrating....if I didnt have these ground lood isolators I would be at square one no matter what I did with the grounds....

Tom

 

it definitely sounds like a ground because you said that when you hooked up the cd player and it was fine, but when you touched it the noise came back. When you touch them, you are grounding the wires by using you. I cant remember if you said if you tried using a diff pair of rcas or not.

 

i cant believe i missed this, try this behind the radio run a wire from the ground to the outer ring on one of the rca's not the tip just the outer ring and see if the noise on that channel disappers... pioneers are notoriuous for blowin grounds on pre outs

 

i was just going to suggest this too. you beat me too it.

 

when I ground the ring on the RCA the noise gets real bad.

keep the ideas comming

 

Have you gotten rid of the RCA's or changed them yet? Could just be shyt rca's making what may be a tiny problem in your signal gigantic when it is amplified.

Have not seen this said or done yet .. make this your next change please

Fej

 

 

tried new rcas running in the niddle of the car...same senerio....I think there is too much electrical interference in the C5 ....so the rcas are picking it up...

Tom