My car (2005 Cooper S) pings between 2200-3200 rpm, I have always run 91 octane. The only way I can get it to stop is by mixing 91 & 100 octane 50/50 (yielding 95.5 octane fuel.) It has done this ever since I purchased it 1.5 years ago. Some have suggested I have a vacuum leak, but I can't hear one, & I have looked. In the past year, I have made the following modifications (which have had zero effect on the pinging): 17% Alta pulley, JCW airbox, 450cc injectors, ECM flash from RMW in Anaheim. The car runs very well, as long as it has at least 95-96 octane fuel.

Do they all ping, or is something wrong with my car? I will add I have had no check engine light codes until very recently, when I got a P2096.

 

they're meant to run on super unleaded really, forget mixing it, just put the good stuff in, especially with a pulley fitted.

 

I have always run super, it still pings.

 

It is possible the bypass valve has failed, or as others have stated a possible hose off.
Do an OBD2 scan and see if any codes pop up. If you have a lean burn issue, it could be from the issues above.

There is always a clogged fuel filter and or a failing fuel pump!

 

Only code I have is P2096, & that only showed up in the past week. It's been pinging since I bought it, unless — as I stated — I run high octane fuel.

Speaking of the code the rear O2 sensor failure?

 

When you have a downstream sensor code, it usually means a lean condition, which usually means an air leak in the system, which goes back to my original post.
There also may be a timing issue, where someone went in to the computer and changed the timing, which could have been done by a tuner. If it is firing too soon, it can cause a ping (detonation) which is extremely hard on the engine components.

 

It's not the bypass valve, that seems to be functioning normally.

 

Turns out it was a plugged catalytic converter causing the pinging; ostensibly because of the high boost the plugged converter was causing. Replaced the whole exhaust system with a custom high-flow (& very low noise) system, & viola! No more ping! The converter was so plugged you could not see through it when held directly up to sunlight!

A clear case of one thing leads to another to another...