ECU Acceleration Anomaly

[MotherTucker]

Here’s something interesting. An R8 technician at a local Audi dealership called me and asked me to bring my car in for him to test. Another customer is having an issue of a very noticeable hesitation under specific circumstances, and the tech was at his wit’s end trying to solve it. He asked to try it on my car to see if it was “normal” for the car. So the tech hopped in the driver‘s seat with me in the passenger seat, and sure enough, he was able to duplicate it! Just wondering if lots of us have it, or is it less widespread than that? My car has a manual transmission by the way.

To do it:

1. Drive the car up into third gear.
2. In third gear, bring the engine to exactly 2,700 RPM. That’s 1 ½ ticks below the 3 on the tachometer.
3. While still at 2700 RPM and in 3rd gear, floor the accelerator, and hold it floored for several seconds.

My car begins to accelerate, and then has a big hesitation where it loses almost all power, and then a few seconds later does the acceleration. If you miss hitting 2,700 RPMs or it’s in a different gear, it won’t do it. I suspect it would do it even in an R-Tronic.

So, off my VIN goes to Audi (along with the VIN of the guy who found it), so they can look into it. The tech thinks it's the ECU (computer that controls the engine), but he said it it could perhaps be something in the air intake system.

If you think of it, give it a try and let us know if this is a widespread problem or not.

mt

[bz888]

Hmmm, haven't tried this yet, but I get that momentary hesitation during hard acceleration and shift from 1st to 2nd in R-Tronic! How do fix that?

[conm]

bz888 the 24R4 software update makes a huge difference to R tronic. Make sure it has been done...

[Whirlinturbin]

MotherTucker -- that had to my car he was working on.

[MotherTucker]

Yes, I think so. It'll be interesting to see if others can duplicate it, and what gets done about it (if anything).

mt

[KfabR8]

Just for grins, even though my car's been worked over (TT managed by APR), I tried it this morning.

2700 in third, nail the throttle and right at 3100 it falls on it's face for a second - and it really makes the turbo system unhappy. The waste gates blow off the initial charge that's starting to build, the car sort of coughs, takes a breath and then it starts going again.

I was able to make it do it twice, but was in some traffic, so I couldn't really let it go after it got past it's little stumble.

I plan on trying again when I can let the car stretch it's legs just a little more. I want to try it in second and fourth just to see if it's not a WFO throttle entry into the turbo system that makes it purge for a second.

[rmicroys]

I'm going to have to try this out when I go out for lunch. What's the road speed at 2700 rpm in third anyway?

[MotherTucker]

Normal city street speed, maybe 30 MPH or so. Easy to do without going real fast.

[ianerrid]

Just tried it on mine and it just lunges at the horizon until blue lights appear in the rear view mirror. US smog spec anomaly perhaps?

[the_buch]

Just tried it on mine and it just lunges at the horizon until blue lights appear in the rear view mirror. US smog spec anomaly perhaps?

Are you R-Tronic or manual?