Slight Hesitation in my RS6.

[oce]

OK, I've had my RS6 for about two months. Picked it up from it's first owner with 13k miles. During hard acceleration in any gear, i get some hesitation in the engine. It is barely noticeable and inexperienced drivers do not even notice or feel it, but it is there and my local Audi dealer has confirmed it. They were unable to determine it's cause but are still researching it. Otherwise, they gave it a clean bill of health.

Anybody have any idea at all what it might be? Could this be a normal part of the acceleration.. the vehicle is still very fast.

The only option it is missing is the "loud" exhaust. It has the "quieter" exhaust.. every other option is on this vehicle.

Woody

[SpinEcho]

This does not sound normal. When does it hesitate - immediately after you ask for acceleration or after the car has started to accelerate?

[Silversleepa]

Wait a minute..they "confirm" your issue, but give your Beast a clean bill of health..? sounds fishy...you need to lean on them a bit I think..does it hesitate on every gear when you stomp it or when you "pinch" the accelerator to WOT?..also do you know your "turbo lag" points when you step on the gas (yes..the car does have some lag...) if its lurching, youve got issues..if on the other hand its "slight hesitation" followed by a "giant sucking sound," and your butt-o-meter lighting up green, your car is fine and your other vehicle is an F1 car if u think the rs6's spool time is an issue :...hope your problem is not serious..to me it sounds electrical, which will suck to fix, especially, since your dealer thinks your car is "OK"...that means the diagnotics won't/can't find the issue(s)...good luck

[sturs6]

Welcome to the boards Woody!!! Sorry to hear the beast is sick.
Where in the Carolina's are you located? Unless that is not what NC stands for then ignore that question!!!

[Rally]

Try some high octane gas. The ECU might be retarding the engine power due to detonation.

[Dark Knight]

OCE -

i experience the same kind of thing -- sometimes, it's certainly not consistent. It feels more like the transmission doing something than the engine but that could be just how it feels to me. I had my car chipped at 7K and wondered if it had something to do with that but I can't confirm.

When I turn ESP off it doesn't do it, so try doing that and do quite a few hard accelerations and see if your car still hesitates. If it doesn't then I think it's what a technician told me: the ESP can intervene and give a sensation of hesitation.

See how you go and good luck, I hope you get it sorted out!

[nene]

I would start with the engine throttle adaptation as well as ESP off.

If you have access to a VAG tool, do some logging as well. If you don't have a VAG tool yourself, you can find one here . Log MAF results and boost for starters.

[JAXRS6]

When my RS6 went in for its first service beyond an oil change (I'm at 41K mi now), tech said plugs were fouled with carbon. A lot, if I recall correctly, possibly due to too much "Mr. Milktoast" driving. As someone pointed out in one of the earliest posts here, these cars -- engines at least -- are meant to be driven hard.

Suggested remedy from dealer to prevent this in the future: Mix a bottle of Techron with up to 12 gal of gas, then follow with a bottle of octane boost in the next tank. Repeat every few thousand miles and/or as the need is indicated by performance.

It seems to help, and this last time, it really helped after I added two bottles of Techron when I filled up (instead of one bottle for "up to 12 gallons"). Techron comes in small doses with all Chevron gasoline, but the bottles are much more concentrated and do seem to help keep the plugs clean.

Turbo lag is another possible cause. The RS6 doesn't have a lot, but it's there and may seem odd if your prior vehicle was not a turbo.

[Hy Octane]

Sounds like it could also be the turbo bypass valves acting up..

[oce]

Ok, to answer everyones questions:

1) It hesitates about 1 time for every 1500 rpm's between 2k and redline on a hard take off, never on anything but a hard take off (peddle 3/4 or more). Basically about 3-4 times.

2) It hesitates every gear, which leads me to believe it may be an intake/outtake issue.. thought it might be this "quiter" exhaust restricting airflow...

3) there is no sucking sound... how would i notice this.. in the car or out of it?

4) I get compression at around 2500rpm, maybe 3k.

5) I live in the Charlotte area. I notice you do too.

6) What is a butt-o-meter? lol

7) I only use high octane fuel in all of my vehicles.

8) I will test the ESP suggestion, thanks.

9) I will tell the techs about the carbon, I am going back in a couple days.

10) I have had severak vehicles with turbos (my favoritae so far was my 87 turbo coupe thunderbird, lol). This is definitely not "turbo lag".

11) I will tell the techs about the turbo bypass valve

Thanks all.

[Silversleepa]

woody...do you know if your car was ever chipped? ecu or tranny...just an outside guess b/c i'm not a tech, but could it also be the clutch "program" trying to recalibrate itself to your (assumed) stock ecu...unfortunately, it could also be damage to the plate itself or some other internal hardware issue...now that I think of it, my old Ford (before it died) had the same issue, and it was a trans problem amongst other things...eventually the trans died hope that's not the case with your Beast, but just my two cents as to symptoms...if you're lucky, it will be the intake values at worst (cheaper/faster to fix than the trans)... hope you can fix the Beast to enjoy the great summer weather...BTW, when you roll down the windows (hey, its not winter anymore) and you pinch the accelerator down, you can hear the turbos spooling up (the "giant sucking sound").. good luck!!

[oce]

Yeah i do hear that sound from the turbos. I believe it is stock, and was not chipped. I was planning on getting the APR chip upgrade sometime this fall.

I do know this, after I drive it hard for a while, it's got a sweet smell of "hotness" coming off the undercarriage. I am not sure what else to call it.. just a hot smell... not bad, but sweet like. not rubber, not fluid.. maybe metal? the brakes maybe?

[LIRS6]

1) It hesitates about 1 time for every 1500 rpm's between 2k and redline on a hard take off, never on anything but a hard take off (peddle 3/4 or more). Basically about 3-4 times.

The above is definitely not normal - mine pulls consistently through the rpm's - maybe a hesitation early rpms which I think represents a slight turbo lag. Fyi I have the "quieter" exhaust. I would discuss with the dealer the re-set the tranny program, as Nene expressed.

[SpinEcho]

My vote is for bypass valves after reading your detailed description. Good luck and let us know what you find out!

[sturs6]

oce you have a PM!!!

[Shadwell]

I had a slight hesitation on mine, and when I took it to Audi, they diagnosed the following faults: 1) Gear Signal Sporadic and 2) Maximum Boost Pressure Exceeded. They didn't know what would cause the fault or why it was intermitent. The car was booked in to have the fault fixed and that was five weeks ago! The air mass meters have been changed, a number of switches and sensors have been replaced and the fault remains. An Audi Master Technician test drove it and the fault happened to him. As a result, Audi UK sent 2 Master Techs to the dealership in order to fit two new turbos (it's a two man job, apparently). Will keep you posted as to whether this works. Has anyone else had anything like this happen?

For the database, mine is a 2003 RS6 Avant in Avus Silver with Black Leather interior.

[nene]

They changed the MAFs but not the bypass valves also? These were known to go bad very often on the S4 in the USA, so I would think that would be an easy try as well, given the issue.
I'm beginning to wonder if I should change mine as a precautinary measure. I was at a dyno meet yesterday, and we talked about this very topic, and had decided to do so. Too bad the parts dept at Clair was closed yesterday.

[Hy Octane]

Hey Nene.. You might have a look at these...

http://www.hoppenmotorsport.com/bypass1.htm