Macster

Then I'm currently out of ideas.

Sincerely,

Macster.

paradigm79

OK, thanks for the tip. I will take a look into that as well. I drove the car into work today with the aluminum cover panels on the front and top of the engine, but I left the carpet covers off so I could hear a little better. At times in the past the noise seemed to stop with clutch depression, but other times not. This morning the noise seemed to be attenuated when pressing the clutch, but not go away completely. Then as soon as I would release the clutch the noise would get slightly louder. All of this was while leaving the transmission in neutral.

I also tried pressing the clutch in and putting it in neutral while I slowly rolled to a stop. It was difficult to tell over the bit of tire and road noise but I couldn't really here the noise. If it really does go away that still makes me think its a drive train issue.

As a side note, every time I shifted around 3000 rpm I could hear a very short bbbzzzzzzz. My guess is a heat shield buzzing but I thought I would throw that out there in case its a clue.

Macster

From your most recent posting now the noise might be explained coming from perhaps a noisy (bad I don't know) clutch release bearing.

If the release bearing is more than noisy, going bad, this might result in some excessive play that allows the clutch lever to move about and this can contribute to the noises you hear.

Only you are at the car. You have to be sure from where the noise is coming from and under what conditions.

This almost always involves getting the car in the air (safely) and from under the car id'ing from where the noise is coming from. In some cases a helper has to be in the car working the clutch, the gas pedal, and so on.

Sometimes you id from where the noise is coming by determining where it is not coming from.

You have be very very careful and aware of what you are doing.

Get a piece of clothing, or a hand caught in a serpentine belt or touch a hot engine exhaust header or a converter... There'll be a noise from under the car alright. A high-pitched girly scream of pain. Understandable to be sure but something to be avoided at all costs.

Sincerely,

Macster.

No HTwo O

Macster, I think he did this already. I assume a TOB- throw out bearing is the same as a clutch release bearing. Right??

paradigm79

Yep, at least that's what I called it, maybe clutch release bearing is a more appropriate name.

Finally, an indy porsche shop opened up somewhat near me so I buttoned the car up and made the drive over there. Before going his first guess over the phone was DMF as well, until I reviewed all the things I had inspected and replaced. So we put it on the lift and based on the quality of the noise, the fact it runs great otherwise, doesn't burn oil and it could be heard on both banks, he felt it is a bunch of sticky valves. And since it could be multiple valves contributing, it makes it hard to pin point as the sound truly does move around as different valves could stick with every rotation.

He felt this could be from running poor quality fuel and specifically fuels containing ethanol as he's seen that lead to really "gunky" valves and guides. So his suggestion was to find ethanol free fuel, buy quality fuel (that's about as hot a topic as which oil to use) and finally use a fuel and/or oil additive to help clean the gunk and/or carbon out. Then basically drive the hell out of it to help the process along, not a problem.

If he's right about all this (which I hope he is), ironically letting the car idle so much recently in an attempt to find the source may have actually exacerbated it.

So, can anyone recommend a good additive they've had success with...there are tons out there to choose from.

No HTwo O

The Chevron Fuel System Cleaner with Techron. Run a couple tanks through the ststem. Refill with fresh fuel. And then change your oil.

No HTwo O

And I use this web site to purchase ethanol free gas for my toys:

http://pure-gas.org/index.jsp?stateprov=NC

Macster

Not too enamored of that sticky valve explanation. The valves could only stick open and if they were open the engine would misfire some and then something fierce after the valves burned from being kept off their respective valve seat.

But try a bottle or two of Techron. Use according to directions. And I always change the oil/filter after I run down the last tank of gas with Techron added.

Sincerely,

Macster.

paradigm79

Yeah, I wasn't either when he first said it and asked him a lot of follow up questions. But like I said in the very first post, this intermittent noise was also accompanied by a slight hunting at idle. So based on his diagnosis and your comments about misfires, maybe its true. Its never been bad enough to register as a misfire, but some cylinders would show retarded timing at idle (but not off idle) according to my Durametric. I decided to trust him and keep it revved up on the way home, and even without any additive yet it seemed to be a bit better by the time I got home. I will report back after I get some miles on it.

paradigm79

Fuel additives to free up sticky valves has not done the trick, so I'm back to the drawing board. I still have yet to get any CEL or engine related codes through my Durametric but I still wonder if the REVO flash has any effect on the DME reporting codes.

I started inspecting the two variocam plus solenoid/actuators first with the Durametric and then later with my multimeter. The valve timing solenoid read 10.7 ohms while the valve lift solenoid read 12.7 ohms. Readings from both banks were exactly the same. From old posts concerning the original single solenoid variocam system, I've read the solenoid should read about 13 ohms, but I don't know if that's true for the new design. Anyone know? If so, then I guess that points to having two bad valve timing solenoids.

When actuating each with Durametric, what should I monitor and what should I expect? So far I've concentrated on monitoring cam angle. When I actuate the valve lift while at idle it kills the motor, and I haven't tried this at higher RPM yet.

When I actuate the valve timing at idle I don't really hear or feel a change, and only see a small blip on the cam angle plot that drops down from 0 to -250 on the Y axis (what are those units?), however the blip is sometimes much smaller. I'm not sure if that's real or a function of the sample rate. Again, I'm not sure what it should do, should it hold the timing advanced/retarded until I stop it or is that blip normal?

Macster

I'm always a bit leery of aftermarket flashes that could (I say could) as part of their intent mask/ignore some errors.

You might consider -- depends I guess on the cost/effort involved -- resorting to a stock flash and then seeing if while the noise is still present if there are any error codes.

I do not know about the 987 solenoid/actuator voltages. However, I just read through my references for my Turbo and the resistance measurement of the solenoid hydraulic valve should be between 8 to 12 ohms at 20C.

Also, in testing for possible faulty variable valve lift function this is done with two people in the car and the test is activated "immediately before acceleration with wide-open throttle". This is from my Turbo reference.

At the level you are diagnosing you really need the right numbers, the right test steps for your car and its engine. The first rule of working on your own car is do no harm to anyone or to yourself, and last do no harm to the car. Without this you risk damaging what may be a perfectly healthy engine.

To get the numbers/test steps for your car you might see if a sympathetic Porsche dealer service department would share with you a section of its solenoid/actuator check/test steps document. I can sometimes get this info for my cars but I've always had one or more error codes along with engine symptoms to justify (to me anyhow) my request for info. The few times I walked in and asked for something of the blue... it has not been forthcoming and I never pushed my luck to see if I could get it by insisting.

You want to eliminate what it is not but still, I find it hard to believe that with no error codes (ignoring the possibility the aftermarket flash may be doing something behind your back) and no real engine misbehavior that even one of these is bad, let alone both.

But if you suspect them...

My reference shows a X/Y plot that suggests the 0 to -250 could be in mV. The plot is referred to in a test that checks the CMP (camshaft position sensor) signal.

Honestly, though I think you're looking a bit too far afield. If there was anything wrong with the systems you are looking at I think you would have more reasons to suspect the VarioCam Plus hardware or anything related to the camshaft drives like serious engine misbehavior, error codes, debris in the oil/filter.

However, I can't say 100% you are on the wrong track. I'm after all not a professional Porsche tech (or any automotive tech for that matter).

Sincerely,

Macster.

paradigm79

Yeah I pretty much agree with everything you say. If nothing else I'm learning a lot about the systems on this car and I've been thinking about getting a stock flash to eliminate that variable as well.

As for being a professional porsche tech, the dealership near me couldn't figure it out either and just guessed it was a broken valve spring. I can't say they're wrong until I take the cam cover off and have a look, but I might as well do it myself than pay them if we're both guessing.

I've rebuilt a different motor before and its nothing magical, just tools, patience and some information. Too bad Porsche isn't so forthcoming with the latter anymore, that's really what's so difficult about working on these newer models.

Anyone know who manufactures these solenoids?

Macster

A broken valve spring is a possibility. I've come across only one Boxster (I forget what MY but I'm pretty sure it was pre-2003 MY) with a broken valve spring. I never heard the engine run. By the time I spotted the car the head was off and cam/valve hardware was on the tech's bench under a dust cover awaiting the ok from the aftermarket warranty company to authorize the repair.

I believe I mentioned earlier that if the valve spring were broken that I would expect to see some bits of valve spring metal in the oil filter housing oil and oil filter element but maybe not.

If the spring snaps cleanly and doesn't come apart...

At the point you are at now, removing the camshaft cover from under which it is suspected (strongly suspected...) the noise is coming from sounds to me, a reasonable next step.

Porsche is very tight-lipped with its info. I had reason to look into some OBD related info for Porsches and essentially what I learned through my contacts is Porsche just doesn't share this info. Much the same goes for the factory manuals and stuff.

In fact, a while back a dealer told me its PIWIS diagnostics computer system quit working 2011-12-31 at 11:59:59 which left it with just its new PIWIS2 diagnostics computer system. This I guess is an attempt by Porsche to prevent these older generation diagnostics computers from falling into the 'wrong hands'.

Kind of funny: The problem is the new PIWIS2 diagnostics computer system does not work with cars older than MY 2004...I believe an update to correct this is in the works. I hope so. My cars are both pre-2004.

Oh, and I was looking over this PIWIS2 diagnostics system a while back and the screen displayed some sort of expiration date just a month or two into the future. It appears to me in order to keep this PIWIS2 diagnostics computer system alive requires periodic updates and a reset of its death clock. No doubt the dealer has to pay a hefty fee for this.

I've rebuilt or helped rebuild maybe 10 or so engines in the past. I'm a big believer in having as much info (and cross checking it) before I do a rebuild.

Now sometimes -- depended upon the engine -- when I'd take the block/crank/etc to the automotive machine shop the counter person could rattle off bearing/piston/cylinder fits/clearances and so on from memory. This info and all like it was available everywhere. Having this much access to this kid of info took some of the worry about a rebuild.

I'm older now and do not have the time or the energy (or the place, or the tools/equipment) anymore to tear into engines. Even if I had the place and the tools and the equipment (and I could have all it takes is some money) I do not have the energy and I for sure do not have the energy to do this in the dark so to speak.

Oh, I just looked at some pics of a new VarioCam actuator and solenoid and I could see no company name or logo anywhere. All I managed to see was just the part number and what looks to be some kind of marking that indicates when the part was manufactured.

But maybe I need to look closer. I have pics at the office, but I have both parts (I think) at home. Let me look for them tonight and I'll see if I can spot a company name.

(I also looked at the old passenger side door lock assembly and all I could spot besides the part number and what looks to be some kind of marking that indicates when the alum. housing was cast was a "Made In France" inscribed on the housing.)

Sincerely,

Macster.

paradigm79

Yeah I guess it could be a broken spring, but myself and just about everyone else thinks it would definitely throw some CEL codes and run much rougher, especially at high RPM whereas mine only idles rough. I spoke with a REVO dealer that's somewhat nearby, he says the tune can be switched off and it would revert back to the factory tune without requiring a re-flash. He doesn't believe the tune changes the threshold or prevents any CEL codes from being reported (pretty much expected him to say that) but he's willing to switch it off for me until I get this sorted.

And I know what you mean about not having the energy to do this kind of work "in the dark," so far I've spent way more time on the computer hunting for any bread crumbs of info than I have working on the car. That gets pretty tiring quickly. Thanks for your input, I hope to get the REVO turned off tomorrow and we'll see what happens.

paradigm79

Well after taking it to the indy shop and getting a full physical the consensus is timing chain slap/******. According to the mechanic, he called everyone he knows to discuss the symptoms and noise and apparently there have been many cayman/boxsters that have behaved this way. I was advised it is a culmination of minor wear among many parts in the system and that trying to fix it is a waste as it won't hurt anything. If you try you have to tear the motor apart and you are still left wondering which of the many parts need to be changed to tighten everything back up.

A few months ago the dealership also hinted that it could be chain noise (which it does sound like as well) as they had already replaced a chain on a cayman.

Hartech talks about similar issues here, particularly #8. http://www.pistonheads.com/gassing/t...p?h=0&t=983171

Not real happy about it, but all the "pros" are telling me to just drive it. If they are wrong I sure hope i get a code before I get a big boom. Thanks for everyone's input.