As I said the nasty pic circulating that I was privy to was of an Audi dfi motor. The accumulation of deposits would happen over time and while it has been seen to affect the rear of the intake valve it was a thought. As for the need to run a cleaner through the motor, this has been discussed in Excellence. And no, the sky is not falling, Howie's motor has developed a ping over 25k miles. Overly lean mixture, excessive compression, low octane fuel, timing problem........of course we are going to speculate.

 

All of the above could be involved in the pinging you are experiencing (and add to that low pressure fuel pumps). Take the car back to the dealer and talk directly with the master tech. Explain to him that it's a real issue and that he should examine all possible causes. He will get to the bottom of it and resolve it.

 

what rpms are you turning when the pinging is going on ? The manual for my 2008 C2 states "do not lug the engine at near 1500 rpm for extended periods...increase revs", or something to that effect.
If I'm in 3rd gear and barely rolling and try to hit the throttle, my engine will ping like hell until it gets higher than 1500 rpm.

 

OKAY I have some updates. I have been experimenting and have come up with some interesting results.

After the DME update from PCA (Porsche Cars Australia - Factory owned by Porsche) I drove regularly for about 2 full tanks of gas.

The pinging was eliminated to about 95% What I mean by this is that it would still "clack" away when in PDK normal, automatic mode traversing a slight grade with partial throttle. But this would be a very SOFT ping. It would be so minimal such that even a casual observer trying to listen to it may miss it. But I notice EVERYTHING!

To add to this, I had been experiencing a regular tyre clicking noise which eventually revealed itself to be a F*@# screw, (self-tapping of course) embedded in my brand new rear ADVAN AD08s. Leaving nothing to chance, I had the tyre removed, repaired internally & plugged; I am of course diverting from this topic, but only to say this brought about the conversation on the pinging with my tyre guy.

My tyre guy mentioned that some cars can be particularly sensitive to fuel; especially when changing between brands. Each 'brewer' has their own mix of chemicals that markets itself to either clean, optimise or boost fuel economy. Blah; Whatever! But then it started to dawn on me; I had, in recent miles, been changing between different brands of fuel over the last 10,000 miles when previously I had just stuck with BP fuels.

So I decided to stick with the BP brand; even sticking with the same station. This had an almost immediate effect; it reduced it to almost no-ping at all. Must be fuel!?

I took it a step further by purchasing octane booster; 7-RON points boost over the highest pump RON available; 98RON.

Now, this had totally eliminated all pinging- even trying to trick the PDK by letting it go up a steep incline, then switching to manual and upshifting as far as it would let me. The car would then lose speed trying to stay in-gear to the point when the PDK just HAD to down-shift. No ping whatsoever. I could not get it bastard to ping in any way, shape or form.

I did this for two full tanks of octane boosted fuel, estimated to be now around 100.4RON. This is interesting and concerning at the same time; the manual recommends a minimum of 96RON.

I took this information to one of the Porsche Workshop's techs (not the head-tech) and he mentioned that they do take this data from customers right up to Germany by way of some process (I forget the acronym) and they can adjust and calibrate DME specific for that customer (and for all customers too).

In the last full tank, I filled up again with 98RON plus HALF a bottle of the booster, with the same positive result. I filled up again TODAY with a full tank with the remaining half of the booster.

In summary, I still don't know whether or not it is the fuel or that the DME is still not right or if there is something going on in that flat-6. All I know is what I have done to date, and hopefully you guys here can decipher and come up with some sort of conclusion while I continue try this 'booster' method of eliminating the ping. I will keep the data I have collected for the head-technician at my next service which is coming up soon.

Thanks for all the suggestions so far!

Cheers,
Howie!

 

Interesting. I just experienced my first pinging today similar to what you describe. i just washed my car (2011, C4, 6MT), which only has 1800 mi. I had an oil change last week using Mobil1 0w40, so i wasn't sure if that had anything to do with it, or if it had to do with my handwash 5 minutes prior. Was planning to post today, but noticed yours. I'll be sure to keep track of this thread or add any input if valuable. thanks and good luck.

 

I use exclusively 2 local Shell stations and sometimes one Mobil station. From what I can see muself and from what people spoke - Shell is mst reliable one here, they seem to dillute gas less and octane number seems to be higher/closer to what it should be.

you can also start buying octane booster and add it to each tank of gas you buy. it is still cheape than to switch to proper racing grade 100 octane gas.

 

We should remember that the RON is not what is posted on the the fuel pump. The pump octane number is an average of the MON ( motor octane number) and RON ( research octane number). So, for a given fuel, a pump number is equivalent to a higher RON number.

 

Interesting thread- I have occasional ping in my 06 when blipping the throttle for downshifts. A real pisser. Running 5w50 and always the best gas, change plugs and air filters more often than required. To me it seems the drive by wire throttle input is laggy for 'blipping'. Actually have to do more of a "mash" than a blip to perk the RPM's up.

What I've heard, and what might be the culprit of the ping is that the throttle input sensitivity is on a curve- at very light input with the gas pedal in the 0 position, or even with a very quick action, it is not a true 1-1 ratio at the throttle when you blip like a cable driven system. The farther the pedal is pressed the more it becomes 1-1, and there seems to be a bit of a 'buffer' on quick blip input. I think it was designed this way so soccer mom's would not put the 911 through the wall or garage door accidentally.. lol.

I know that Vishnu makes a black box for Audi cars and a few ricers that lets you very easily re-map pedal input sensitivity, it is a shame that no one makes this for pcars. I'm also a bit chapped by the design from Porsche- It's a sports car for christ's sake.. we don't need a toned down gas pedal.

BTW have tried running 100 octane, it does not make a difference in this respect at least per my experience.

 

That would be dependent on where you live. I am from Australia, and my post relates to actual RON which is displayed at the pump.

Howie

 

It's been finally figured out and in a totally unexpected way!

To cut the story short, the issue was the HIGH PRESSURE FUEL PUMP! My belief is that the pinging was caused by an under performing pump leaning the mix. Although the ECU cuts back the timing it still rears its 'clacking' under light loads where the pump isn't providing the required pressure at small throttle angles.

To weave a longer yarn; I was bringing in the car for the end-of-2nd year warranty extension. The service dept specialist advised me there was a warranty campaign for high pressure fuel pumps; with my car to have its replaced during the inspection. It would take 4 hours.

I did not think much of this, as they said it was 'preventative action'. I went on my way and during the day I had decided to look up on it; stories of people with 997.2's having total fuel system failure, towed back, etc. It didn't seem to be my case.

After picking up the car, I drove to my dressage class (Yes I love to ride) thinking about the lesson and not paying attention to the car. I thought it ran well at first, but something was different... It was actually fantastic! I ended up being late to my lesson because I was doing laps around the stables... I had slowly realised the cause of this dead-buried issue that I thought was only in my head!

The car now, feels like it's got a new motor with an extra 20hp with a crisp and sharp throttle; as if it were an Arabian being given a good inside-leg kick with a good crack of the whip! Yeehar!

It is only in hindsight I had realised that over 2 years my car had slowly become more-and-more sluggish. This was masked by my daily driving habits of long drives (35,000 miles in 2 years). It felt like an old turbo car but without the power; just the turbo-lag. Octane booster would help but not very much and only temporary. I had basically given up and not really thought any more of it - it would do this 'clack' thing every now and then and I would just live with it.

It even got to the point that around town, I would use 'sport' mode just to get it lively enough to enjoy it - I couldn't believe I didn't feel that was 'just wrong'?!

With the HPFP replaced, the hesitation I would get between PDK gearshifts is now gone. The jump off the line is spirited and alive, my foot no longer depresses the throttle an inch - then another to get some more power only to back off because the car would surge forwards (like an old turbo car).

My theory about how this happened is like this;

The HPFP is not performing as it should. It's not dead, but slowly dying. It was not delivering the required fuel at small throttle openings. Perhaps it's just not giving enough fuel the entire rev range, leaning the mix and getting pre-detonation. The ECU sees this and retards the timing - but can only do so much. It does what it can and sits there, making the overall experience feel sluggish. If the throttle is opened enough the HPFP manages to give enough fuel and the car suddenly wakes up and shoots forwards.

Had I been driving the car more spiritedly or at a track-event, the HPFP would have surely exposed its dying health - like those who've had total failure or CEL and 'limp home modes'. This didn't happen to me as it's my DD doing a lot of freeway work. I believe over time the pump would continue to deteriorate and give out like the rest.

It's been only a few days since I had the HPFP replaced and I haven't touched the 'sport' button yet!

You know about that thing people say about killing a frog by slowly boiling it in water? I felt like that was me, except in reverse!

Glad it's sorted now, I can stop sticking my ears out the window listening for that dreaded clacking sound and get back to driving!