SDB

My 2001 A8L has been pinging at low RPMs and under load since the day I bought it. This is not a momentary ping -- I can get it to ping indefinitely under the right conditions. I live in California and the best I can find is 91 octane. The dealer has checked it out four times and has not found a problem, saying the pinging is perfectly normal. I find it hard to believe that pinging is OK and have always understood that it does engine damage. When I pressed the dealer on this I was encouraged to add octane boost with every fill up (I don't think so) or drive 50 miles to find 100 octane racing fuel (again, I don't think so). Is my dealer correct, or do I have a problem?

4AudiQ

even thought the specs call for 91 octane,
I now use only 87 octane and NEVER get pinging.
I buy the cheapest gas I can find, and I live in So. Calif.
The Fitch Fuel Catalyst changes the molecular structure of the gas and the ability to use lower octane is one of the benefits.
I can't vouch that it will do the same thing in your 4.2L V8, but I have over 1 year's experience in my V6 that it works beautifully.
At $3.39/gallon, I am quickly paying for the cost of $150.00.<ul><li><a href="http://www.fitchfuelcatalyst.com/">http://www.fitchfuelcatalyst.com/</a</li></ul>

meatwad/beefcake

the reason you have no pinging is that your engine computer dialed back the timing to accomodate the crappy gas. Have you ever passed a science course in your life?

MP4.2+6.0

are you sure it has the right spark plugs and they are fresh?

if you really wanted to, you could dial the timing back a few degrees with Lemmiwinks with a serial VAG COM if you know what you're doing technically.

meatwad/beefcake

this is a problem that can crop up due to a couple of things... normally a bad knock sensor will cause the ECU to dial timing *back* and reduce pinging as well as max power. There is a chance that one of the two knock sensors could be damaged in a way that causes timing to be advanced or simply not retarded the way it is supposed to be but this is unlikely.

Make sure you are running the correct plugs and you have new knock sensors.

The engine and transmission work together to time the engine based on the load and a million other things, so there could be a fault in the wiring there or one of the sensors. There could also be excessive deposits on the valves or pistons due to oil leakage past the rings or possibly a leaky fuel injector (least likely).

You should never hear this pinging in a Audi because the Bosch active knock control is one of the best in the world.

The dealer is full if **** in this case and you should try another dealer or a specialist that can confirm experience with the A8.

CA_A8

I am probably a little late with this reply, but I have the exact same problem and would love to stirr up the discussion again. I have changed the MAF, the plugs (twice!) all coil packs, 4 injectors (one side of the engine) changed on of the two knock sensors, fuel pressure regulator, did the Techron bit to exhaustion, logged a bunch of hours on my commute with VAG-COM to find a hint where this comes from, paid 2 so called specialists a fistful of dough for no progress - and yes, I retarded the ignition by over 7 deg to keep the engine from what I am afraid is certain destruction... and yet, the bloody thing still knocks!