dds28

My 2012 Cayenne S with 21k miles has an intermittent knocking sound during light acceleration for as long as I can remember. I have tried all brands of fuel but has not made any difference. I noticed that it only happens after the engine is fully warmed up (oil temp). It sounds like a diesel engine when it knocks, as if the engine is running lean.

The dealer can't seem to find the problem and yesterday just reprogrammed the DME. I find no difference as the sound is still there. Any ideas as to what is causing this? I read a previous thread on the same issue but no one posted a solution. Any help in finding a solution would be greatly appreciated.

Andy E.

Most 4.8's will knock or ping under light acceleration. Porsche AG is aware of this issue and insist that North American premium fuel is sub-standard to Europe's fuel; hence the pinging. I've tried using 104+ Octane booster in an effort to reduce pinging but have found no difference.

FWIW, the pinging will not occur during cold winter months. However, I'm sure that cold is a word that is least used in Hawaii....;-)

Slow Guy

I have a real hard time accepting that excuse. If the DME can't adapt to our premium w/out pinging how could it be expected to adapt to some 2nd world countries fuel? That excuse sounds like BS to me.

dryadsdad

I agree with Bill. I feed my CTT 91 RON/MON fuel which is a heck of a lot better than I'd get in Mexico (in many places) and I'd expect my machine to adapt to that MX fuel. BTW, I"ve never heard that on either the CTT or our 993 so I expect there is something more going on here.

That pinging isn't just a noise. It's an indication of excessive engine wear and loss of power. You are damaging your engine by this well above normal use wear and tear. I'd suggest you contact Porsche N.A. and see if it confirms your dealer's claim that they know about it and are utterly blase about the condition.

user 83838290

Hope you'll get it fixed.

Can't help it, this reminds me of...

Andy E.

The pinging is very light and barely audible unless you're next to a wall or median. It only occurs with a warm/hot engine during light acceleration and not heavy acceleration or heavy loading; where you would be more accustomed to hearing the traditional pinging.

This could also be a sensor location issue where it cannot pick-up the pinging due to its proximity to the cylinder in question. But then again, what do I know....? ;-)

dryadsdad

It doesn't belong in a properly managed modern engine at all at any time for any reason. The loudness of it isn't a metric of the harm it's doing but rather the sound insulation of your pepper.

dds28

Andy E. - cold in Hawaii for us is when the temp drops to the high 60's

I did notice that if I drive in sport mode the pinging/knocking sound goes away. But the minute I turn it off it knocks, esp. right when the transmission shifts into a higher gear, always light acceleration under 1500 rpm. I feel that with modern engine management and knock sensors, this shouldn't happen. Something is not right. It can't be too good for the mechanical components of the engine. I think I am going to go back to Porsche to have them look further into it.

Slow Guy

+955

mclaudio

Has dealer used a boroscope to look inside the engine? I had a similar knock on an older Cayenne and this is what my dealer did to further investigate.

dds28

No they haven't looked inside the engine. How do you convince to look? I wonder if that a procedure that is covered under the warranty. I would think that if they don't get paid for doing this extra step, they might be unwilling to do it. I will definitely ask though. Good suggestion.

virkdoc

Damn if the cars are still knocking with premium gasoline my engine should have exploded by now!! Here in India using normal fuel which is almost always mixed with kerosene and is 87 octane......maybe I have a knock too but am used to it??

mclaudio

You're correct - I had mine done when under warranty. If you're willing to pay the labor for diagnosis, I don't see why the dealer won't do it.