Warm Engine Won't Start!! What Could It Be???
 

Car started fine this morning. Drove the '01 2.7L A6 around for 25 miles or so. Parked. Did a little shopping. Came back out. Tried starting the car and it won't turn.

I noticed that on the second turn of the key, NONE of the diagnostic lights came on (should be on before you do the final turn with the key to start the engine). Upon turning it all the way, the starter will simply turn and turn and turn but it won't fire up the engine.

Tried that a few times and finally it started. Went home, turn off the car, and tried to start it again. SAME DEAL!!! So it's like WTF... I just bought the car a week ago. The battery shows 14 volts. What could it be????

Battery? Distributor? Spark Plugs? Contaminated Fuel? I mean... why wouldn't the diagnostic test lights come on?

Lots of possibilities...
 

Historically, these symptoms would point to either leaking fuel injectors (or other fuel delivery-related issue) or a failing sensor of some sort.

There may be a DTC in your system that would tell you which sensor is failing, if that's the case.

Sounds like possibly a bad ignition switch.
 

I had one fail on my urS4. Acted in a similar way.

The ignition switch caused the engine to turn over but not start?

Might be the Thermostat...
 

I had that EXACT same thing. Whenever I tried to start my car within an hour of running it, it wouldn't start (well, it took FOREVER) to. When I finally started, it smelled flooded. However, it would start cold no problem. Took to the dealer and they replaced the thermostat. Basically, because the thermostat was bad, the engine was flooding itself when warm.

But Why No Diagonostic Lights????
 

You know how it's a three step turn to start the engine?

Step 1 - Enables power to turn on radio.
Step 2 - Enables power to all features of the car (except starting the engine). The diagnostic lights would all come on.
Step 3 - Starts the distributor/starter. Will start turning until engine fires up.

In my case, all the diagnostic lights do not come on. The service tech says anytime like this happens, usually it'll fire up a code and the check engine light will come on (ie... thermostat failure, moisture in gas, O2 sensor failure, etc). In this case... nada.. nothing.

What could be wrong here???? Bad ignition switch???

They took the car in today. They'll be looking at it first thing on Monday.

Here's An Update....
 

I called in for an update... and they said that the vehicle threw NO codes whatsoever.

So... do you guys think it's a bad ignition switch? Sounds probable...

They got a "lock porter" to look at it now.

FIXED!! Bad Ignition Switch is the Culprit!!
 

Here's an update:

They found that the ignition switch is faulty so they went ahead and replaced it (Part # 4B0-905-849). Couple other things were also listed (43 WAU and 10 WAU), whatever that is.

So the car is now starting fine again and I'm back on the road! Woooohoooo!!! Thanks guys for all your input!