jsoderbe

Hi guys,

I have gradually noticed something getting progressively worse on my car, and I have always gotten great help here before!

Anyway, it is a 2001 Carrera Cab, with 120 k miles on it. It has worked great, and still does, during the 3 k miles I have driven it. In the beginning it was so smooth, and fast. The AOS was broken when I bought it, and was replaced without any problems.

However, it has always had a tendencey to have an unsteady idle, and the rough running test in the Durametric has shown high values. No CEL or any errors shown in Durametric.

My concern is that the last month or so, I have noticed a slight hesitation around 4 k rpm, and a vibration from the engine/trans from 3000-4500 rpms or so.

There has also emerged something that sounds like valve train noise, like a hydraulic lifter not working properly. It only comes when I rev the engine.

Could it be related to the dual mass flywheel? I can feel the clutch vibrating, and I have a feeling I am closing in on a clutch job.

So, do you recognize my symptoms?



Regards,

Johan

Byprodriver

Ageing: MAF, Vario-Cam actuaters & chain wear pads, DMF, engine oil, ...

Byprodriver

Engine & trans mounts, fuelpump, clogged injecters,sparkplugs,...

Macster

My advice would be to with as little (ideally none) engine running as possible get the car to a pro and have him diagnose the cause of the symptoms.

The noise you mention could come from many places to name just a few like a loose spark plug, or a leaking exhaust -- last thing touched on purpose or be accident during the AOS repair for example -- but it could be something unrelated to the AOS repair, like a broken valve spring or a bad lifter.

The vibration can be from the engine not running as smooth as it should and having a different vibration harmonic which the engine mounts, etc, are not tuned to deal with as well as if the engine were running with its normal smoothness.

Certainly the dual mass flywheel can be a cause of the vibration but less likely (highly unlikely) to be the source of the engine noise.

Dual mass flywheels have been known to break (the dual mass feature that is) and cause not only odd clutch engagement/take up but other symptoms.

Regardless if any of the things above are or are not what's going on none of them will fix themselves. Someone somewhere has got to get his hands dirty.

And the more you engage in self-diagnosis the more risk you assume from if the symptom is the tip of an iceberg serious problem doing more damage.

The engine may be sick but not deathly sick. (My 02 Boxster experienced a failed VarioCam solenoid/actuator and was clearly sick, sick, sick, but was healed/cured by having the bad parts replaced.)

Get the car to a pro. Describe to him as best you can what happens and when and let him earn his pay by diagnosing what's going on.

Sincerely,

Macster.

jsoderbe

Thanks, great advice. I just wish we had a good Porsche mechanic in my city, but we dont, unfortunately. So I am afraid I have to diagnose it myself.

The solenoid should produce a CEL, shouldnt it?

I cant say that I have experienced any lack of power, besides the slight hesitation I sense when the vibrations start. And the vibrations seems to vanish with higher revs, or at least I cant feel them.

The DMF seems to work, the clutch engagement is normal but I can feel a vibration when pressing or releasing the pedal. It feels like a slightly worn clutch.

I guess it could be a broken valve spring or a bad lifter. How do I diagnose that?

Could it be IMS related? Could be a bearing rattle.


Thanks,

Johan







Regards,

Johan

jsoderbe

I read some threads, and it seems like I should start with the throttle body cleaning. Then MAF, then check plugs for fouling, then try to figure out which bank has the rattle.

Pic of the car:




Thanks,

Johan

Macster

Before you do anything else, unscrew the oil filter housing and dump the oil into a *clean* (spotless!) drain pan and carefully examine the oil and the filter element for any scary bits. What you see or do not see is important.

If you see scary bits -- post pics! -- you're done. The car (with *no* engine running) has to be taken to a qualified shop for professional attention.

If you see nothing in the oil, then you can clean the TB but if it is dirty there's another problem. The only time I have bothered to clean the TB of any of my cars is when I removed the TB of my 02 Boxster in an attempt to diagnose what proved to be a bad AOS. The TB was dirty, oily, with a puddle of oil behind the TB at where the hose from the AOS connected to the intake manifold. The TB clean helped for a few minutes then the failing AOS oiled the thing up again and that coupled with the other things a faIling AOS does the engine just got sicker.

But before you bother with the TB cleaning, that noise I think is more important.

It is out of the ordinary and out of the ordinary noises always come before dirty TBs.

You need to as best you can with as little engine running as possible ID the source of the noise. Where the noise comes from really determines what you do next.

BTW nice color! My 02 Boxster is that color and I still think its beautiful.

Sincerely,

Macster.

jsoderbe

Hi again,

I finally had an hour to look through the great advice from Macster above. Just to prepare you; this is not easy things to present on a picture, but please see me trying below.... :-)

First and foremost; I replaced the oil filter cartridge and saved the half quart of oil that came with it. Then I cut out about a fifth of the filter material, and took a few pics with flash and without.







Last one is the flash picture. The black particles you see on the pic doesn't seem to be ferrous.

I continued by first sweeping my magnet in the half quart of oil, thouroghly. The magnet looked like this afterwards:



Then I swiped the filter element, and that added this much on the magnet:



Don't know if you see the difference, but the amount of stuff on the magnet maybe doubled. Any thoughts? Should I scrape the filter to gather all the particles? The oil has maybe 2000 miles on it.

So, I continued to remove the air filter housing to access the TB. The TB had some residue, not much, so I swiped it clean. After cleaning it looked like this:



Only thing is that it doesn't close all the way? There is a few millimeters gap there.

I looked around the engine, and it looked nice and dry:





Couldn't see any missing cables or hoses. I followed the vacuum lines, and they were correctly connected. But, I found this black rubber hose stuck behind the air pump (?) in the left back corner of the engine bay:



It is straight but I bent it to get all of it on one fick. It is about a foot long, less than 5 millimeter ID.

The MAF looked super clean, but I guess that one is impossible to see if it works or not:



Any thoughts on how to check the MAF?

Regarding the vibrations; when I drove it into the carport, I tried to feel how it ran. It is clear that the vibrations are there from start, meaning from idle and all the way up. Once you guys clear the oil residue or not I will start it up and try to catch the rattle on a youtube clip.

Please let me know your thoughts!



Regards,

Johan

DBJoe996

My thought - Truthfully if I had an oil filter that looked like that I would be making a call to the credit union for a second mortgage in order to fund a rebuild or replacement engine! I would not start that engine again until at least you pull and check the IMS/bearing...might as well replace it at that point. I would get that car to someone who is knowledgeable about what you are facing and can give you some professional advice. Hate to say it, but it really looks like you have some internal engine problem and if you continue to run it you run the risk of complete failure vs. repair. Just for contrast...I have a 99 C2 with 120,000+ miles, no vibrations throughout the entire RPM range, no funny sounds or ticking noises, runs and sounds as sweet as a sewing machine. I never have any particles whatsoever in the filter/oil. I am not an IMS freak by any means, but you've got something going on and you need to get in there and find out what.

jsoderbe

Wow, is it that bad? I didnt think that I had a problem with just these few tiny particles present. I have seen other filter elements with big shiny chuncks of bearing material in, and mine looks nothing like that.

Maybe I should remove the oil pan? Maybe there is where the most of the stuff end up.


Regards,

Johan

knfeparty

Well I was just going to say that filter didn't look too bad. The black non-ferrous bits are usually things like chain guides and it's kind of normal. Ferrous stuff is never good of course.

Every 996/7 I've ever been in idles a bit lumpy compared to a smoother layout like an inline 6 you might find in a BMW.

Generally the IMS bearings don't give much of a warning sound-wise. If the IMS bearing was going I think you would see a lot of larger particles in the filter.

Gotta say you might not be able to "Rennlist WebMD" this one. If it is really bothering you just take it in to somewhere that has an actual Porsche scanner; more than likely the stealership. Also how did you mount those 997 wheels on your 996?

speed rII

Hi Johan,

Your filter looks good to me.
Remove the oil fillercap when engine is running, if there is no change in the idle there is intake leak some where. Maybe AOS (again) or in the oil fillertube. Both are known issues wirh these cars.

Allso check the sparkplugs and airfilter.

jsoderbe

Hi,

there are several different 997 "S" wheels, and there is only one specific offset that works. I believe it is the 2S wheels, the 4S has the wrong ET. I can verify if you want to know? I had to mount 10 mm spacers in front, though. I think the wheels look great on the 996! The car also has a GT3 kit and H&R springs.

Regarding the oil; I thought so too, meaning it wasn't anything extraordinary. The ferrous particles are really small and very few, and I would have guessed that any engine has them in the oil filter. But I can be wrong, that is why I really appreciate any thoughts from you guys.

The lumpy idle would be ok, if my Durametric didn't say the "rough running" value was too high. I guess that indicate a problem. Plus the rattle, which sounds like a non-functioning hydraulic valve lifter.

Ideas on next step? Should I start it and try and get a clip with the rattle? Or take down the oil pan?


Regards,

Johan

Byprodriver

Definetly need to drop the oil sump plate & see whats in there & clean the oil pickup. The metal in your filter was after only 2000 miles so I would be concerned.

DBJoe996

+1 on Byprodriver. That is what I was getting at...that much "stuff" in the filter after 2000 miles? You are asking fellow posters and members a dangerous question...should I run it or not? My opinion was not to run it and find out exactly what is wrong, or run the risk. I guarantee this - if it is something like a stuck lifter, rod bearing, IMS bearing or some other internal component going bad - run it and you will soon find out exactly what it is. I would sigh heavily and realize that it is time to bring in a professional or go in yourself.