Problem believed to be with Aluminum Flywheel and Crank sensor(sort of long).....
 

Well after battling with annoying "limp mode" issues for almost a year, Germantoy mentioned that he had the same problems due to his Aluminum flywheel from Tmtek. I also have a Tmtek unit.

I just pulled the engine and took some measurements of the size/location of the CPS pin on the flywheel and sure enough the dimensions are way out of spec. Tmtek machined the flywheel incorrectly.

For anyone who is having similar problems (search my previous posts for the exact symptoms) here are some of the dimensions. Keep in mind i took these dimensions and they are not exact. All are in millimeters.

Pin length (stock S4) = 10.12
Pin length (tmtek) = 5.0 (WTF!!)
(Note: The S4 flywheel is offset forward an additional 0.79mm so the difference in lengths is really more like 5.91mm)I could have been more accurate with a godd@mn hacksaw.

Audi spec: sensor to pin clearance= 0.45-1.25mm

S4 actual sensor to pin clearance = 0.90mm
Tmtek sensor to pin clearance = 2.08mm(again WTF!)

Just by looking at the sensor in relation to the tmtek pin, the end of the pin barely reaches the outside diameter of the sensor, when it should actually at least reach the center of the magnetic sensor. On top of that, the pin is too far away from the sensor. Here are pics of the two pins. I believe Germantoy had the bracket machined to bring the sensor both closer to the pin and also closer to the flywheel to make up for the short pin. Since i have the engine out i think i am going to try to get a longer pin with a full diameter (tmtek's has a flat on it??) and make up the difference by milling alittle of the bracket to bring the sensor into spec.

Sorry for the long post but this has been kicking my @ss for the last year and as a mechanical engineer this horrible example of manufacturing has totally pissed me off, so hopefully this info will save someone else alot of time.

<img src="http://pictureposter.audiworld.com/51125/enginepull_1_6_07_sized.jpg">

<img src="http://pictureposter.audiworld.com/51125/tmtek_pin_sized.jpg">

<img src="http://pictureposter.audiworld.com/51125/dualmass_oem_pin_sized.jpg">

nick was ready to round up a posse and string up TMtek last year...

oh man im sorry this was the problem it sounded so familiar when i heard it the first time
 

I will tell you this TMTEK is now Klaus Euromotive same location just one bay over, the owner is Peter Blaser he will not stand behind his products what so ever and is a douche bag. If need be i can give you my lawyers number if you want to know your rights as a consumer. But yes its misengineered horrendusly i went up there to show them just how bad it was and there head tech at the time Glen agreed.

Yeah, i had talked to them and they told me they never had a problem with....
 

the flywheels (after i had heard your story), so i think i am just going to try to fix this problem myself.

But was i correct about you finally getting the flywheel to work? I mean are you still using it now?

thanks!

doh!