So my buddy installed my new stereo system into my 92 sc300 and there is a horrible high pitched whine that goes up with the engine RPM. This guy has been doing stereo installs professionally for 10 years and he is just about stumped! The power and speaker wires are run down opposite sides of the car, the amps and headunit are grounded properly and cleanly (he even sanded down the paint inside my trunk to get a solid ground.) It's all brand new JL audio speakers and amps and a pioneer head unit. My buddy even hooked up his RF amp is place of mine and it still made the sound. I even bought brand new Kicker ground distro blocks but that didn't help anything.

I just ordered a grounding kit for my car but I'm hoping that isn't the problem.

Anyone have any ideas?

 

Figure out where the noise is being introduced. Use a test RCA at the amps. If he has been doing it for 10 years, he will probably know the proper procedure to tracing a noise to the introduction zone... GL. I know it sucks to have noise...

 

Forgot to mention he tried a test set of RCA. I think it has something to do with the head unit because the sound starts as soon as the head unit turns on.

 

ive encountered a few pioneer head units with this problem, try grounding the rca outputs, i can draw a diagram if needed, what happens is sometimes the rca's ground circuit takes a dump from various stupid reasons, not saying the radio ground is bad but just the part that grounds the signal or shields the noise in the rca's, its alot easier then it sounds,,, thats my 2pennies for yah...

 

I'd love to see a diagram. I'm willing to try anything at this point.

 

well i took some pics as its easier than drawing under the influence, this is all for example as i dont have a headunit here with me that i can use...
heres the rca and ground wire, strip back the ground wire

fold over as shown

place ground wire in rca

and plug rca into the back of the headunit, ( the barrel connecter is acting as the back of your headunit,

and what this test will tell you is that if it corrects your noise or even makes it better, than theres a problem with the headunit,... oh and also i didnt mention it but make sure the other end of the ground wire is at a good ground, if the headunit is grounded good just tap it into there...

 

I think he might have tried that already but I'll definitely give it another shot tomorrow. Thanks

 

what model pio headunit is it?? was it used? and if so did the original harness come with it?

 

F700bt,used, original harness

 

oddly enough i had that issue with the same unit, but it screwed up due to installer error, so maybe a different or unrelated problem, but where in flo r u, i was an installer for 13 years so if you need a little trouble shoot help just holla

 

oh what i just remembered is that if the harness has a resistor inline with either ignition or constant, see if its burnt or reading the wrong resistance, or you can just bypass it to test if that clears the noise up...

 

I'm in Niceville, FL. Way in the NW panhandle.

Did you use a harness to plug your head unit in? My buddy hard wired it in and worked first shot (aside from the ground noise of course).

Also, idk if this means anything but when he was hard wiring my radar detector, he pressed a metal pick onto the metal brackets that hold the head unit and there was quite a bit of sparking. He said that might be the problem if there is too much current traveling through the brackets. We'll probably mess around with that tomorrow too.

Seems like this car is just a grounding nightmare >_>

 

im lost after all that,lol. but yeah im way to far to do anything about it, but last thing would be to make sure the ground wire is hooked up to brown from the factory radio harness, i guess thats all i got besides actually checking it out, but good luck and let me know the outcome

 

IT WORKED!

Thank you so much, this was exactly the problem. The second he touched a ground wire to the outside of the rca output, the noise went away completely. Oh, sweet sweet silence He soldered a ground to the outside of that output and it works perfectly. I'm so happy. He was kinda annoyed that I didn't mention this idea earlier LOL.


Thanks again

 

I'm surprised that a professional installer of 10 years hadn't already tried that solution. And, I wouldn't use that a permanent fix because it can cause more problems down the road. A headunit's outputs are supposed to use a floating ground which is not the same as the vehicle ground. Without getting too far into the specifics, it causes problems and you actually have to disassemble your Pioneer unit (or send it out for service) and have the floating ground fuse replaced that is located inside the unit itself for the RCA outputs....