Help needed for an engine noise unsolved problem

[cayenne69]

Hello Doctor,

I need help for an engine noise problem at warmup and nobody can't find the cause. If you can watch and hear the sound of the engine at warmup, I will be more than happy. The first 30 secs at fast idle is normal, but exactly 30 secs sharp when back to normal idle, you can hear the horrible sound from V6 engine on 04 Cayenne. Every morning I think the engine will die. I sent a video like this to the Porsche's dealer and nobody can't find what causing this and they told me "everthing is normal"

Please get the popcorn and watch my engine video at temperature 46 F (8 C)

No code from Durametric except a lot's of misfire cyl #1 and less from 3 and 4 and others. New coils packs and plugs changed twice with OEM parts, 0w40, air filter. Few clues, we changed both cats last year completely jammed, and I was reaching about 40 mph with pedal squeezed in the carpet, without any CEL and nothing on PIWIS from the dealer... My feeling engine running too rich with black deposit on exhaust tips. I notice also a 1 sec lag on kickdown to get the full engine torque and it's not from transmission.

I don't know where to starts: coolant temp sensor, timing chain guide, injector, secondary air pump, mass air flow, variable intake shifting rod (what i suspect)

Please post your diagnostic and experience like this,

I'm desesperec and waiting for your help.

Thanks all of you.

Edited April 18, 2009 by Loren
Made video viewable here

[Orient Express]

Probably the secondary air pump coming on. If it only happens at cold start, and just a bit after startup, and then goes away after a minute or two, that is what it is. This is a standard VW part on just about every engine VW makes (the Bugatti Veyron has 2 of them). My Audi's air pump sounds like a vacuum cleaner with rocks in the blades.

I don't think you have anything to worry about.

[por911]

You might consider having someone look into the cam and cam chain tensioner area of the engine, asap. Sounds like a broken/failed tensioner at a min, and or something is rolling around that cam area(piece of guide, nut, etc).

Regards

[RFM]

Remove the engine cover (just pull off, no screws) and take a look on the right rear side of the engine, there is a kind of AOS and a bunch of pressure and vacuum valves in the area. Try to hear of the noise comes from that area, it's sounds like if you loosen the oil filler cap, the noise will go away or changed in frequency (fluctuating vacuum in the engine ventilation system)

[wvicary]

I think you have a problem in the valve train also. I would remove the valve cover for inspection. Does the noise go away off idle?

[cayenne69]

When the engine is warm, it running like a new one. If I start the car and leave immediatley in less than 30 secs (what I'm actually doing) there is no misfire or any knock when I drive, even with engine cold, and sometime in montreal it's very cold... This happen only on slow idle for about 3-4 mins max depending on ousite temp. If I press the gas pedal to increase RPM to 1500 like the fast idle does, it's much better. When the car is hot and I stop then engine for a quick stop of 5 mins, if I restart the engine and put to drive in less than 10 secs, there is a lag like the car is running out of fuel for 1 sec and suddenly accelerate. Same lag of 1 sec on kickdown.

Thank you all of you, I'll check all your diagnostic, and leave you feedback.