time4a911

Hello Folks,
I recently got the ignition noise through my radio, but ONLY when the car is on, thus I am pointing at a bad ground.

I have a '99 996 with the Hifi Nokia sound system.

Can some please tell which wire is ground on the radio harness and frunk amp?

Thank you all.

DBJoe996

Brown wire is the ground wire.

time4a911

DBJoe996

If the radio is using the stock wiring harness, then the brown wire is ground. If the amp is aftermarket, hard to say unless, again, they used the stock wiring harness to connect the amp. You might either have to do some wiring tracing in the frunk or find the wiring diagram for the Nokia.

time4a911

DBJoe996

Stock radio and amp it is then. It is the brown wire. I believe the ground point is right next to the battery in the frunk. Pull the battery cover and look next to the battery on the wall. Also the main battery ground is there and it might be a good idea to clean it up and check for any corrosion.

time4a911

Thank you.

time4a911

Hello Again,

Things tried:
1) Located block to chassis ground, clean with wire brush and reinstalled - still getting engine noise
2) Grounded radio directly to the battery negative terminal - still getting engine noise
3) Grounded amp directly to the battery negative terminal - still getting engine noise
4) Cleaned all negative leads to battery terminal - still getting engine noise

The car did get an engine out service and new coils were installed, if that makes a difference.

Thanks,

DBJoe996

Maybe you need to put a RFI filter on it.

cds72911

I always try to go back the the last change before the problem was introduced. If you had your engine out and coils replaced, and the interference started right after that, it seems like an area to investigate.

time4a911

time4a911

Update: Buzz still happening on my car.

- I checked the new coils and the part number is Beru 0040100177 which is the updated coil pack for the 996 model.
- I have added noise filters at the amp and radio - did not work
- I tested the radio with direct power to the battery
- I tested the amp with direct power to the batter
- I checked the grounds, cleaned and reinstalled.
- I checked the connections to the coils

- I don't want to take it to the shop and spend a few $100


I'm clueless




Tags: Porsche Carrera 911 996 Radio noise bad ground buzz

DBJoe996

It's a long shot but about the only other thing, given all that you have done, is bad diodes in the alternator voltage regulator. How many miles on your car? You could test this out by removing the serpentine belt and running the engine for just a very short period with the radio on....see if the buzzing is still there. Other than that I do not have any more ideas. Might be time for a professional installer to take a look.