'06 S4 rpm fluctuations

[JeremyT1169]

Hi folks. Bought a 2006 S4 automatic with 63,000 miles five days ago (clean carfax, 2 owners) and have noticed when cruising steadily over flat land in high gears at 1,500-1,800 rpms or 40-50 mph for the first five minutes or so of a drive before the engine is fully warmed up the tach bounces consistently 80-120 rpms. Because it's the V8, it's quite noticeable and, considering I just bought the car, somewhat unnerving. I'm in Connecticut, so the weather is nice and mild albeit a bit humid right now; i.e., harsh temps are not the issue. Video of the tach in action follows. Any help would be much appreciated. https://vimeo.com/43782842

[Tarrant]

Could be a bad MAF,
Could be carbon buildup (maybe try a seafoam?)
Could be bad plugs,
Could be bad injectors,
could be bad coil packs.

If I was you, I would just do the 55k Service (which covers the sparkplugs, and fresh fluids never hurt) - but make sure you do the seafoam BEFORE you get the plugs done - they can be fouled by the seafoam application.

I had slight changes like this on my V8 - and I did crankcase AND Intake seafoam applications. 1 note though - if you do the seafoam in the crankcase - My Indie suggested I change the oil AGAIN in a few weeks to make sure there is no residual sludge in the system.

[JeremyT1169]

Thanks Tarrant. Very much.

[Tarrant]

No problem - I believe if you test the resistance of the MAF you can tell if its Funked or not (im sure a quick google could help)

[JeremyT1169]

thanks again. I will repost with a resolution soon. hopefully.

[nugen]

Maybe you need to reset your throttle body alignment? Try disconnecting the battery for a few minutes. When you reconnect the battery, turn the key to the run position for a minute or two. You'll hear the engine going through the procedure. When it's done give it a drive and see if it helped.

[JeremyT1169]

took it into the shop with notes including the throttle reset. thanks. whatever it is, it's tied to the engine being cold, or relatively cold. which makes me think it's not electronic. but i know very little of the mechanics of the car. am learning swiftly, tho, for better or worse. we'll see. thanks again to you both.

[Tarrant]

Any new developments?

[JeremyT1169]

indeed. thanks again for the effort. it's the torque converter. common issue with the tiptronics apparently. have yet to receive official word back from the dealer today -- communication is not this dealer's strongsuit -- but I found these last night after the service writer hinted at the torque converter. They were to drive it for the diagnostics this morning. I'm a little baffled by their lack of professionalism in not returning my call, though. I'd understand if it were GM ...

http://www.youtube.com/watch?v=kdmL68HIBVE&feature=youtube_gdata_player

http://www.audiforums.com/forum/b7-models-71/subtle-surge-rpm-pulsing-178931/

[Tarrant]

Let us know if it was in fact the tip (I have one too - have a bit of a jerk between 2 and 3 sometimes, and 3 and 4 sometimes also)

[JeremyT1169]

it was. i would suggest taking it to a transmission shop if it's out of warranty. the good ones will do a free diagnosis.

[UMich Hockey]

The same exact thing is happening on my B7 S4. How much was the repair?

[JeremyT1169]

around 4 grand. if you're a loyal audi customer, i would suggest taking it to the dealer and appealing with them and audi of america to help pitch in for the fix. fortunately, the jeep dealer I bought the car from paid for it -$500.

[jbizzyblox]

how bad was the idle a brand new torque converter was the fix ?it was 4k at audi $500 at an indy mechanic?

[JeremyT1169]

Idle had nothing to do with it. The Jeep dealer paid for it minus $500, which I agreed to pitch in. Did not consult an indy or transmission shop.

[tprivratsky35]

So the problem was the torque conv.? i have a 2004 s4 with tip and im experiencing the same problems trans shop cant seem for find a fix

[JeremyT1169]

if you've watched my video or similar ones, and it's doing what i've described, then it is indeed the torque converter. just tell them you know that's the issue. but they have to 1) find you a torque converter, a part that doesn't exactly hang off trees, and 2) entirely drain and remove your transmission, install the TC, then refill the tranny and put it back in. The labor is 80 percent of the cost.

[tprivratsky35]

ya its amost identical to you video and the way you described it. i was told they can rebuild the stock ones stronger. Was that not an option?

[JeremyT1169]

I had it done at the dealer, so no. And I won't even venture to speculate, though I know whatever causes so many of them to fail has apparently been redesigned for the new ones they are installing. I would imagine the right folks could rebuild it, just like anything else. But again, the torque converter part of it is not the major cost factor. That would be the labor to get it out and reinstall it.

[JeremyT1169]

i will add, though, i would be leery of a shop that's telling you they can't get you a new one but knows they can rebuild it "stronger" ....

[tprivratsky35]

ya i was looking online and i can get an ace conv. for 425 brand new. Did you have them look at your valve body? I was told they could make the shift points quicker by adjusting them. That sound like something to pursue or not?

[JeremyT1169]

good question. don't know enough about transmissions to have an answer for you unfortunately. Never had any issues other than the from-start frustration, when it often can't decide whether to be in second or first. it's only a split second, of course. but it can still be annoying. i've found putting it in sport mode eliminates the hesitation, as it forces it to stay in first. but still, not ideal. my only gripe about the car, though, so I should shut up already....

[tprivratsky35]

ill have to do some more research on that but thanks for the help.

[TarlCabot]

http://www.youtube.com/watch?v=kdmL68HIBVE&feature=youtube_gdata_player

YUP, that would be the t/q :(

[tprivratsky35]

Replaced the tq and that fixed the problem thanks for the help