Sounds like pinging since its happening under acceleration.

 

Rocky...thanks for the reply. I don't hear anything when the windows are open...shouldn't I hear something then? I had a Pathfiner that had a loose heat shield but this noise is much more faint than that. To me, it sounds like somewhere in the passenger side firewall area but my wife doesn't hear it...she just looks at me like I'm nuts and she could be right. I'm going to just live with it since the car runs fine...and the dealer will probably agree with my wife..."can't duplicate it."

 

I believe it is normal and nothing to worry about. I hear the same thing on my 2011 Pilot and also on my wife's 2011 Accord V6.

 

Pntballgunz...thank you too. Maybe it's misery loves company but to hear that your Pilot does it helps me feel much more relaxed about our Pilot. My wife keeps telling me she loves her Pilot so that's the main thing for me.

 

Mine does it occasionally as well. Has for the last 20,000 miles since new. Sounds like a very slight pinking under light to moderate acceleration. I suspect mine makes a similar noise on cold starts that's only audible when you stand beside the engine. Noise goes away as soon as the ECU goes closed-loop and the mixture leans out (which is amazingly quick these days with heated O2 sensors and other trickery.)

My current best guess is that it's an exhaust sound of some sort, harmonic or who knows what. Don't believe it's actually pinking though, these engines have sensitive knock sensors and if you can hear it from the cabin, you can be damn sure the knock sensor bolted to the block can as well. At any rate, I don't see any reason to worry about it.

I used to drive little french cars which would pinking louder that going up a 1 in 30 grade in 4th gear. Never seemed to do 'em any harm, never had an engine failure and plenty of 'em got well up over 140,000 miles (which is quite a lot for a small carburated Renault) with only the most occasional and token of oil changes. So even if it is a little bit of pinking, I doubt it's doing any significant damage.