I have a '90 C4 and I'm getting radio buzz / noise. It only seems to come on my iPod iDrive until, the buzz increases with engine revs. i have all my grounds checked and everything is tight. I have good RCA leads from the amps, nothing close to any other cables.

I have read the lists and Adrian's book and understand there is a suppressor that was not fitted to '89 and '90 964's.

Does any one have the part number please.

Cheers

Mark

 

Hiya Southampton76
Last person with a buzzy radio had a bad alternator . I think it had a bad diod that was puting out some ac . Does your buzz go away if you pull the alternator belt ?
I don' know anything about a suppressor , sorry . I will try to look around for info on this missing 89/90 part cause I got an 89 .

 

The suppressor condenser is part number #964-645-011-00.

 

And where does it go ?

 

In the engine compartment fusebox.

 

Mahalo J.A.

 

Can you just bolt it in on an older car? Or is there more to it?

 

I fitted one to my '90 C2 in order to try and get rid of the whistling from my radio. It took less than an hour to fit, and was quite straightforward using instructions I found somewhere on this board. The biggest issue was that the cables are a very tight fit.

The downside was that it didn't fix my whistling! I'm going to replace my alternator next.

there were 2 parts needed:-

Interference suppression filter: Part Number 964 645 011 00

Wiring harness: Part Number 964 645 901 00

do a search here for TSB 99101 to find the instructions.

regards
Tim

 

I have a suppressor that plugs into the output from my amp and then the RCA leads connect direct to the supprressor. I bought the part years ago when I had my Audi and have never had a problem with "whistling" since.

I think it cost me £8 from my local car audio store so might be worth trying something similar before paying out for a Porsche part.

 

One needs to determine whether the noise is radiated or conducted then determine
a solution. The alt. can be removed as a potential source by just removing the alt
light temporarily.

One can quickly add a test capacitor (1000uf/16V) across the battery or at the power
input to the audio device. If this solves the problem, a more permanent fix can be
determined, e.g. the Porsche noise suppressor. As an example, to solve a radiated
noise problem, a ground strap can be added to the engine hood. Ignition wires need
to be checked for bad connections or connectors, as that can be a source for
radiated RFI noise.

 

Loren,

How do I remove the alternator light? Also, how do I tell if my noise is radiated or conducted? It rises with the engine revs if that helps.

Tim

 

I installed this in my car and it worked just fine. The noise is gone, except at very high volume.

 

Resurrecting this 17-year old thread I found in my research on alternator whine.

I'm looking into getting the parts for this noise suppressor and having trouble identifying what's what. I'm also referring to the appropriate TSB posted here, which specifies 2 parts to be installed: 964-645-011-00 (the suppressor) and 964-645-901-00 (a wiring harness).

Two issues I'm having finding the proper parts:

1. Part 964-645-011-00 (a $250 part) seems to have been replaced by 964-645-501-00 (a $45 part). This seems a bit suspicious.
2. I can't seem to find part 964-645-901-00. This is supposed to be the wiring harness that goes along with the suppressor, above. Searching for that part number yields a $12 radio **** - not a wiring harness.

Can anyone shed some light on this? Will part 964-645-501-00 work instead of 964-645-011-00 on my MY1990, and is it possible that the complementary wiring harness is no longer needed? The illustration of the new suppressor seems to show it fitting into the car differently than the part it supersedes. I wonder if the new part would fit.

Thanks in advance,
- Mike

EDIT: It seems the radio **** is 996-645-901-00. Oops. The 964 prefix yields something called an "installation set" for about $12. No pictures, though, so I'm a bit hesitant. Electrical parts are non-returnable.
- M

 

Search Rosepassion for the wiring part number. They have an image of it. I bought one from them late last year.

They also have images of the capacitors.

 

Thanks!

So which suppressor did you get? The "newer" one that has a 993 headline, or the "older" one that shows 964? And, more importantly, did it work?
Also nice to see that both suppressors are $42.75 rather than the old one being $250.