sixstar

Sooo... this is weird. I just replaced my radio's amp to get it working.
Now when I start the car up there's a high pitch whine that comes from the transmission. Sounds about like a supercharger and the pitch of the whine goes up with rpm. It does this in all gears as well, including 4th.

Now the weird part... I start the car up and it doesn't make the noise at first. The whine only occurs after the radio turns on. (It has a little delay... about 30 seconds)
I'm confused. lol

Also my tach stopped working around the same time... unrelated or not I dunno... but the tach works when I first fire it up for about 5 seconds then struggles (needle bounces) to stay up for a second or two then just dies.

This rx7 game is beatin' my ***. lol... help a newbie out.

Hazard15301

iTrader: (5)

Hehe. It's not coming from the transmission then. It's electrical interference coming through your radio.

StevenL5975

+1 For the electrical interference scenario.

When I drive in my car with a sferics-reciever onboard, this thing is for detecting/chasing thunderstorms.
It basically makes a lightning hearable, operating in the lower VLF range.
When you turn it on medium senisitivity, you can hear the sound of the sparks in your engine.
Turn sensitivity up and you will get deaf thinking you were onboard on a F-16
Of course you will be able to hear an increase or decrease of rpms.

Kind of same thing that happens with your stereo/radio.
There must be something that is not shielded to surpress RFI in your system.
Newer cars must meet a certain RFI level before going into production.

For your tach, well afaik its got power by one of the coils, I believe trailing.
Could be a loose or dirty connection. Also check your grounds. Never read of a tach going bad.

Steven

sixstar

Not questioning your theory, just trying to understand... if it was electrical interference from all that... wouldn't I hear it from the speakers and not from the tranny?

Also is there any type of fix?

Edit: Also yeah it's from trailing... connectors look clean... guess I should further test with a multimeter and check all the grounds as well.

StevenL5975

Well I thought of the speakers, no clue what it has to do with the trans.
Imho this is quiet impossible if it is electrical related.

Sure in the trans can go something wrong but as you described it just comes on
when the radio is on makes me believe that its electrical / interference related.

Just try and unplug your speakers from the radio, then the pitch should go away.
If you have an aftermarket stereo or some amps installed there could be some wiring issue.
I am not familiar with high end audio systems.

For the tach, someone else has to chime in, I never heard of that problem.
I cleaned the connections to the coils recently, amazing effect, car rans smoother and idle is almost perfect.
I have the distributor system (eu spec), maybe different on yours.

Steven

JustJeff

iTrader: (13)

You have a ground loop problem. It's very common after adding stereo equipment. One possible problem is power cables to close to RCAs. For all of my stereo installs I always alway always run the RCAs down one side of the car and the power cables down the other.

sixstar

Cool beans. Guess I'll just get to it when I replace my interior. Good god is my interior ugly! Previous owner had the great idea of blue and yellow. :P
Appreciate all the help.

RotaryEvolution

iTrader: (30)

yep, it's just noise in your head.. err i mean radio.

3vil

iTrader: (4)

also if you do something odd with the ground to your amp, like run a cable from the amp all the way to the battery, you can get this effect. amp should just be chassis grounded like everything else on the car.