Has anyone had this problem? It happens if I am rolling in 2nd or 3rd gear with the throttle closed and then step on the gas. The engine pings loudly and smoke comes out the tailpipe. If I then step on the gas again, it clears up and runs normally and it won't happen again for a while. I can sometimes duplicate it if I roll in 2nd gear at 3500 RPM, and then suddenly step on the gas pedal. It's like the ECU gets confused momentarily and does not adjusting the timing properly.

has anyone had this problem? Any suggestions?

communicate. The ECU "learns" aggressive driving patterns. If you dawdle around a lot on partial throttle, it thinks you are a "granny" and the changes in timing and fueling that it anticipates coming are "gentle". Now when you "trick it" by nailing the throttle, that sort of action isn't in the memory bank of recent action and the ECU goes "WTF???" for a millisecond or two and has to figure out what the fueling and timing needs to be. Hence, transient pinging. Not sure about the smoke. If it's black then the fuel decision the ECU made was a bit off, however, I don't think you can get pinging AND a rich fuel delivery at the same time.

Drive your car a bit harder on a consistent basis and this effect will diminish (but not necessarily go away entirely). Some transient pinging is not the end of the world. Its when it is sustained for several seconds that damage can be done

hmmm sounds reasonable, but I drive it hard all the time. The problem will happen if, let's say, I attempt to show someone how fast my car is. ;-) I'll roll in 2nd, nail the gas pedal and rrraaap. Then off the trottle and back on again and everything is OK.

I looked at it with my laptop and VAG software. When the engine is at 3500 with the throttle closed, the timing stays at 20.5'. It seems that when I nail the throttle, the timing does not adjust at all... so I have lots of turbo and lots of gas with the timing way up at 20.5. That would explain the ping and the smoke.

But why would the ECU be so confused? The chips are MTM+1 (we think).

"notorious" for pinging, especially on extreme throttle movements like you describe. The chips are just too aggressive for the crap fuel we have here in North America. (They were designed for higher octane fuels). They aren't too bad on 93 or 94 octane, e.g. Chevron 94 that we have in the Vancouver BC area BUT they still give a lot of spikey high boost without the required increase in fuel.

There are two solutions, neither of them pretty: 1) Add toluene to your fuel to increase the octane or 2) get some less aggressive chips from Intended Acceleration (IA), MRC (Mihnea Cotet via Bob Myers in W. Virginina) or some older Lehmann or Wetterauer chips. All of these chip sets are fare less agressive.

Another solution might be a manual boost controller to limit boost to below 22 psi. It would likely help

Even if the ECU has "learned" you are a granny, it should still be able to compensate for ping.

Methinks something else is afoot.

may not be real MTM (that whole thread). I do know from local experience that some "after-aftermarket" chip providers modified "MTM+1" chip sets to make them more aggressive on timing and boost and, in some cases, these chip sets result in significant pinging on less than perfect fuel, e.g. 91 doesn't cut it for sure.

Go for the one that can be adjusted from inside the car with the iginition key and throttle. (an extra $40 or so)<ul><li><a href="http://www.moreboost.com">http://www.moreboost.com</a</li></ul>

A modified MTM 1+ is not MTM 1+. Call it something else. Who makes modified code based on MTM 1+?

The real deal MTM 1+ code pings at or near WOT below ~3000 RPM on 93 octane. The solution is simple: roll onto the throttle. I easily drive around this problem with MTM 1+, 93 octane, and summer weather.

I have less agressive chips I could run, but even driving around the ping issue MTM is way more fun.

Toluene (1.5-2 gals per tank) does fix the problem. Colder weather does as well.

is to roll-on the throttle and avoid sudden throttle openings. When I ran MTM, this is how I learned to get around it.

Or, use 94 or higher octane, which I think MTM +1 was programmed for.

no, I use 91 which is all we can get in CA. Once it gets going, it runs great with lots of power. I know that feeling of minor ping when the ECU retards the timing. This issue is a bit worse.

thanks though.

ya... I should have mentioned that. Also, my MTM chips have a hand written label on them. I'm not sure where they came from.

The Mihnea chips were really slow in my car. The timing would not advance much and I could not get much power below 3000. These chips deliver nice torque around 2500... but occasionally get a little confused and ping really bad. Maybe some authentic MTM's might be different.

thanks...

yes, you guys are right about the roll-on throttle solution. That is a good work around. It's not usually a problem, but every once in a while if I nail the gas this happens. But I have learned to get around it. I was sort of wondering if this was an electrical or sensor problem or something...

thanks for the advice.

yes... I saw these. I wish I had bought one. Instead I have the nonadjustable Bosch 3 BAR PT.

Good idea though. thanks.

<ul><li><a href="http://forums.audiworld.com/s4s6/msgs/101483.phtml">The word from Mike Hoppen</a></li></ul>