Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Weird radio noise about 30 seconds after I start the car

Recommended Posts

This is an annoying thing - that is so trivial it is almost not worth asking about - but annoys me enough that I wonder if its only happening to me or to everyone.

2009 C4S. 31k miles. I've owned for a year or so.

Every time I start the car and pull away, after about 30 seconds of driving the radio makes an odd squelching noise for about 3 seconds, and then returns to normal. It is most noticeable on FM stations. I've owned a lot of cars and I've never heard anything like this.

Does this happen to anyone else. Any ideas what causes it?

Link to comment
Share on other sites

I have a 996 but if 997 is the same, then it could be the SAI pump, which runs about 30s when engine is cold. Does it happen when the engine is warm? Maybe when the SAI pump is powering down it creates some static? It's a WAG.

Link to comment
Share on other sites

James. This is most definately not normal. Modern radio/nav systems are well isolated from noise entering through the power line. It is as simple as putting a capacitor of the right size (depends on the systems impedence) across the power line. If this is bad, and caps do fail, you probably will hear all kinds of stuff such as the pump Ahsai mentions. Things are constantly turning on and off and some items are noisier than others. But, a well isolated radio should "hear" none of this. A dealers response to this would probably be trying to replace the PCM at a rediculous cost. But, I bet any good Nav/radio installer could easily put an additional filter on the power line at relatively minimal cost. They see this problem all the time. Good luck and let us know what happens!!

Link to comment
Share on other sites

I was thinking more about the radio picking up the RF noise generated by the simple DC brush motor. One simple test is disconnect the SAI pump and see if that makes a diff. You may trip a CEL but that should reset automatically once pump is plugged back in and the car driven a few cycles.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.