TomP

Had my 996 since June '07 and it's always had this noise: http://www.youtube.com/watch?v=wFM2m8ocTyo

Since I got it in the summer, I usually had the top down, and I'm guessing that wind noise drowned it out. With the top up, I didn't hear it until RPM's went over 2k. Recently I was installing a new battery and left it running to charge a little bit. When I stepped out of it, I heard the noise even at idle. So it's there regardless of RPM.

I had minor work done to it when I first got it, and I mentioned the noise to the indy doing the work. They're very well recommended (Lynmor Motors) and they couldn't find anything wrong. I've read on here & Renntech that some people consider this ticking normal, although their noise may be different from mine.

Any ideas as to what it could be before I try to get it fixed again?

Thanks.

tom

himself

That ticking sounds like one I had a while back - a cord was being "attacked" by the decklid fan. I moved the cord, zip tied it down, and no more noise .

-td

JBRipps

sounds like a stun gun! Not sure what would cause that sound....have you had the car since '97? Or did you mean '07?

I think td might be on to something. Odd sound....are you sure it's coming from the alternator area?

J

ivangene

is this new to you ? (the noise)
put your finger on the hose that runs from the passenger side of the throttle body, over the top of the trottle body and runs into a circular valve about an inch in diameter with a wire at the bottom of it. It's going to be near where your microphone was but UP near the top of the deck opening right behind that flexy looking hose (I think, hard to tell for sure from this angle but I circled the two highest likely candidates)

put your finger on that while it's making the noise, can you "feel" the noise clicking there?????

Malakas

This post got me listening... with my decklid closed I hear something very similar...

That doesn't sound like valve ticking to me... and anything else could not be that big of a deal. Of course, I could be wrong...

1999Porsche911

Normal. Just the EVAP canister purge valve. You can unplug the power cable to this valve while running and it should stop ticking.

gota911

1999Porsche911,

Cool, I didn't know that!

I thought it might be a "time-grenade" or a device that counts how many H2O molecules are in "Mobile Water."

TomP

Nope. Fan is off and no cords in the way.

When I first got it, I drove it with the top down a LOT. Didn't notice it until I started driving it with the top up.
I checked both spots you circled and neither one "ticked" with the noise.

Does this valve activate based on RPM? Because the ticking changes with RPM. Is it really called the "carbon canister valve"? I'll start searching for the location, but in case I can't find it, where is it?

Thanks for all the help!

tom

1999Porsche911

It is located directly above the alternator. Hose running from front of car along bank one to the EVAP canister purge valve and then to the throttlebody. Valve had an electrical cable connected to it.

It is called EVAP canister purge valve.

ivangene

can you take a longer vid and maybe move around from side to side and near the wheels and under the car... maybe have someone rev the motor while you vid ?

TomP

Did a longer video, but forgot to rev the engine: http://www.youtube.com/watch?v=8M-DpeedRUg

Also checked the canister purge valve and it's not clicking at all.

I think it's coming from the left side.

Other ideas?

tom

Macster

there are about a zillion moving parts in that engine and all (just about) located under very thin cast alum. camshaft covers.

That mic will attenuate the sounds and make even the most benign noises sound like the engine's at death's door.

Couple of things you can do if you want to go to the trouble..

Is oil fresh? Oil with lots of miles can accumulate lots of water/unburned fuel and this thins oil and makes engine more noisy.

An oil/filter change can quiet things down. Maybe. If it does then you know and if it doesn't then you know.

Be sure oil is right viscosity and right type. 0W-40 and synthetic. If you live where it is warm(er) consider if you can find it using Mobil 1 5w-50 oil.

Be sure oil level right. Not too low, not too high.

Absent any symptoms like a miss that might point to a loose plug/coil wire, bad coil, or a loose spark plug, you're hearing the normal valve/lifter clatter these engines (and most if not all overhead cam engines) emit.

Most modern car makers now cover their engines with plastic covers/shields, some with sound deadening material added, to keep this engine noise from intruding and upsetting the driver, passenger.

There's a reason... modern engines are noisy. Lots of valve hardware. Injectors. Long runs of chains that drive camshafts. These require guides/tensioners.

All add/contribute to the noise.

More diagnosis, if you want/can have it done: With engine at idle, warmed up, have each cylinder disabled. Note drop in RPM. The cylinder that causes the least amount of drop (and it should stand out from the others) is the "weak" and therefore suspect cylinder. Why is it weak? If on side of noise and if noise/ticking changes tone or loudness when a specific cylinder disabled then noise could be a worn valve lifter (or one just not pumping up nice and tight), broken valve spring, a noisy/leaking injector, or a weak spark plug, weak/cracked coil, and so on.

Once suspect cylinder id'd then it gets real expensive cause essentially you're paying someone to go in and eliminate possible sources. If tech any good he's going to cost you. If he's bad, he's going to want to replace everything he suspects and he'll suspect everything until he hits the right thing.

And it may be, just thinking out loud, it may be a worn/bad lifter, or a worn camshaft lobe. Just id'ing one of these is the cause is expensive, then there's the cost of making it right.

And honestly, based on listening I didn't hear anything out of ordinary. Some engines just idle a bit noisier than others. Normal.

Sincerely,

Macster.

ivangene

MUCH BETTER VIDEO !

hey, this sounds kind of bad, (not emergency bad) My first thought was something inside the left head or cam area. its possible that its something else, but that was my first guess....

Next i thought, well.... think simple, maybe its an exhaust leak? You might check for that, but i think I would have it looked at by someone at a local shop if that yields nothing.

the video was great I watched it 3 times...good idea putting it right on the alternator as I was thinking it could be that....

washington dc porsche

It sounds like my car after it's been parked for weeks. The last time that happened it took 30+ minutes of driving to get back to normal. Got oil?

omnipresent

I've heard a bad fuel injector sound just like that