Please help diagnose this -

My 05 A has a loud shudder/noise that comes on for around 10-15 seconds and then goes away. It happened first yesterday, and it caused the car to go into limp home mode. Set P0234, P1688, P0130.

I've been searching around, and the 2 leading candidates I see are crank pulley and supercharger dying.

However, I don't see the crank pulley wobbling any when it happens. When it does happen, I see the belt tensioner buck, almost as if a much higher load were suddenly added to the accessory drive. Kinda like the way old cars with big AC compressors would act when the AC cycled on. BTW - it doesn't seem to be correlated at all to my AC.

When it happened to me out on the road yesterday, I thought it might have been correlated to when I push the clutch in/out - but based on this morning's occurrence, I don't think it is.

The other thing is that based on what I've read here, both the crank pulley and SC dying are a constant thing, not something that comes goes.

It will cycle on/off with the car just idling.

-Thanks for any input

 

Update - further observations:

On a cold start, the engine runs fine for anywhere from 30 secs to a few minutes, then the noise starts all of a sudden. When it starts, the tension pulley "bucks" like the belt just took on some sudden load.

Based on my latest observations, once I rev past about 2K rpm, the noise stops and the engine seems normal.

And at idle, turning on the AC seems to make the noise louder. When I turn off the AC - the louder noise continues for like 10 sec. then it goes back to the "normal" noise level.

Once again, sounds like a belt slipping loudly (nuthin subtle about it

I'm removing the belt tomorrow to check pulleys and running the engine without the belt to check for noise.

Sound like anybody's experience?

 

Alrighty -

I discovered that this car has a PRW performance Quotient fluid damper on it - anybody have any experience with these?

Photo: http://picasaweb.google.com/11600802...08588765801026

It rotates by hand freely around the crank. So freely, that I can't believe it's failed (I would expect more resistence, or something not like a bearing feeling). Still - is it possible that this pulley is like a centrifugal clutch and the internal mechanism is RPM dependent? that would explain the symptoms I'm seeing.

Looking for anybody with experience with these.

TIA

 

I installed the same damper on my '05 several months ago. It's a press fit installation since there is no key on our crankshafts. On mine, I had to heat it up to expand it so it could be pressed on. Is your crankshaft bolt tight? The Bentley manual suggests a new bolt be used. Maybe the installer didn't use a new one and it's not torqued properly causing the pulley to slip.

 

searocko - looks like you may be onto something. I removed the bolt that holds it on and will pull the damper tomorrow. I'm hoping there's no damage to the crank snout and all I have to do is re-install it.

Do you remember what temperature you heated it to to install it? I'm guessing it favors keeping the temps low, as it has fluid in it..

 

The instructions said to heat it up for 15 minutes at 250 degrees but I didn't do that. I just hit the center with a heat gun for half a minute or so.

FYI the torque setting for the crank bolt is 85 ft/lbs. The new bolt has thread locker already applied.

I also referenced this thread for installation.

Hope this solves your issue. Good luck!

 

Turns out this was a early pulley that had too large of a hole for the crank snout. Jan/RMW is sending me a properly sized one. Luckily, the crank was not damaged or marked from the pulley working it's way loose and then slipping on the shaft. The inside bore of the pulley is, as expected, all scored up!

 

Glad to hear Jan is taking care of you.