What's that smell??

[Beethoven]

I know, I know, the only thing more hopeless than describing a strange sound is describing a smell, but recently from time to time I get a whiff of something inside the car that has me worried. The words that come to mind are: bitter, sour, metallic. It's not oil nor fuel nor rubber. I don't think it's electrical, as everything seems to be working ok. I'm not sure where it comes from, but it gets into the cabin pretty quickly, perhaps from the front.
When does it happen? I'm not 100% sure, but I think when the car is cold, and it's linked to rpms. Yesterday I had to back up a slope in my garage, and I had to wind the car up to 3000 rpm. Smelled awful. But there's nothing when I ride at 4000rpm at long stretches. Sometimes I get a faint whiff of it after a drive when I open the engine lid.
The car runs fine, otherwise. No smoke at start-up, no oil leaks, great power. Car is bone stock. The only other clue I have is that it happend first after I had a new O2 sensor put in, but like I said, it's not fuel. I'm thinking it's perhaps a shot fan motor (heat works fine), but wouldn't that blow up and be done with it?
Does anybody have an idea?

[Hugh R]

You can get a rotten eggs smell from cars with cats if they had run a leaded gasoline, which poisons the cat. Do they still have leaded fuel in Chicago, they haven't in CA in years.

[Beethoven]

I'm using unleaded, and the smell is much sharper and more stingy than sulphur.

[ken_xman]

Have you been eating WOW potato chips?
Read the back of the package someday.

[kqw]

Have your fuel mixture checked. You may be running rich as this can cause a smell that's hard to describe.

[84porsche]

Strange smell might be burning clutch - leaving the clutch in too long while giving gas and letting out the clutch slowly.

[Early_S_Man]

Possible overcharged battery ...

Check your system Voltage while driving ... anything above 14.5 Volts can cook the battery and cause acidic smell in cockpit!

[Al S]

Overcharging battery has my vote also.......happened to me. Good description on the smell BTW.

[Jgordon]

I'll third that, having had the same thing myself.

[ken_xman]

Sometimes on a spirited drive, I get a unusual smell out of my passenger.

[n8marx]

Sounds like coolant to me.

[Icemaster]

Q. Whats' that smell?

A. Your upper lip.

Fourth vote for battery. a "stingy" smell is probably battery fumes, especially if it's kind of an acidy smell. Just went through this exercise on the wifes Jeep. Clutches burning are distinctly different.

[Beethoven]

Thanks for your vote. If it is indeed the battery overcharging, what do I have to do next?

[MotoSook]

I voltage meter on the battery at high RPM would show over voltage yes?

Your new alternator may have a bad voltage regulator...

[PorscheRB]

I had the EXACT same problem. Nasty smell that you feel in your eyes before you smell it, sort of like rotten eggs mixed with old dirty lacrosse pads. STOP DRIVING THE CAR IMMEDIATELY!!!!!! On high speed driving (Highway) the battery acid vapors are vented out of the car and you wont notice til it's too late. My battery blew up on the way back from Hershey and fried the C/D box. Replace the regulator NOW NOW NOW before it causes any more expensive damage, and check the battery and the areas around the battery for acid leaks. Pour baking soda and water on it just to make sure.

Best,

Ian

[Beethoven]

I think I have an internal regulator, and the alternator and the battery were replaced a couple of months ago. The smell is NOT rotten eggs (sulphur--sorry, I never played Lacrosse), but the battery would make sense.
I just checked the battery bay, and everything looks normal to me.

[Mark McClure]

If you had it after backing up a slope with the car @ 3k then my guess is clutch!....if it was over voltage whilst charging you would get it nearly all of the time.......especially on long runs what the battery is fully charged, it would also get very hot before it cooked itself.

My car is a bit hard to drive and my wife calls it the "too much traffic smell" the clutch plate get a bit of over use in stop and go stuff.

Hope that you get the right answer soon.

Cheers

Mark.....

[john70t]

You can't "check" a battery by looking at it, and do not pay anyone who claims to.
[Come on gents and ladies, at least post "I don't know but it could be...." if the post and the answer is not 100% sure of being correct.]

Get a digital multimeter, unhook the battery, and check it seperately. Then reconnect, and run the engine at above 2,500rpm they should both be close to 12.4(rest)-14.5 volts(running).

If you still have any questions, try a keyword search if you can get through all the "I SAW THIS ON EBAY/WHAT DO YOU THINK" posts and the full page signatures.

An overcharging battery will gas off sulfuric acid to the point the battery steams like a steam kettle(I saw that once). This means replacing the regulator(if it's seperate from the alternator) AND the battery.

[MotoSook]

H: The new alternator that you got from the Exchange should have an internal regulator on it, and the battery might be warm to the touch, but as John stated, a meter on it would reveal something. Be careful. Just because it is new, does not mean it is working correctly. And! Since that is one of the newer things on your car, the new sympthom may be related.

[Beethoven]

Yikes! This would mean that of the two things the Porsche Exchange was supposed to do--oil change and alternator/battery replacement--they got BOTH wrong.
I guess I have to go back there??