Hey guys, don't post much but I know forums are the place to go when looking for some knowledge about specific cars

Anyways, I drive a 2001 Allroad (pretty much A6 avant) with the 2.7t engine.

For the last month or so, I've had an INTERMITTENT problem with starting my car. First off, it doesnt matter if it is 20 or 80 degrees outside, so weather does not seem to be a factor. And this only happens about 1/5 start ups after the car has been sitting overnight or long enough to completely cool down.

So heres what happens (when it does happen),
-I turn the key in the ignition, and nothing happens. After a few more tries, the car will attempt to start up, then die within a couple seconds.
-After each cycle, the car will attempt to idle for just a bit longer each time. However, the RPM's usually do not go much higher than 500rpm, with severe shaking and "puttering".
-Finally after 10-20 attempts, the car will start up without dying. Again the RPM's stay well below the normal cold start-up range and there definitely seems to be misfiring.
-If I press the gas pedal, the car will stutter and struggle to raise the RPM's. After a few minutes of warming up, everything seems to be okay and run as normal.
-Also, I'm pretty sure there is a slight gas odor and I swear on one occasion I saw a little bit of smoke from the exhaust in the first few seconds. So this must mean either the engine is flooding out for some reason, or that is just the result from the normal amount of fuel going into the engine finally being burnt off after the car finally starts up and stays running.

Yes, the CEL came on and the only code I pulled was the "Coolant Temp Sensor...". I bought a new sensor and installed it right away thinking it'd be a simple fix. However, the problem came back 2 days later and the CEL is throwing the same code.
I know there is a slight chance that the new sensor is bad too, but not likely. Also, I know that one problem can cause others like a chain reaction, causing the computer to throw a code that is irrelevant to the source of the problem.

I went ahead and changed out the fuel filter, thinking that was a possible issue....but that still did not fix the problem. I also replaced the spark plugs...again, no fix.

The city I currently live in does not have an Audi dealer, or any shops that specialize in VW/Audi vehicles. There is a VW dealer in town, but they said they weren't sure if they would be able to diagnose the problem since VW vehicles do not share the same engine I have. So basically I am hoping someone here can guide me in the right direction to pin-pointing the problem so I don't have to drive 350 miles to the closest shop I know of capable and trustworthy enough of working on my car.




(idk if this is allowed or not but I am going to make copies of this thread in the A4, A6, and Allroad forum sections since all 3 vehicles share the same engine I have...2.7t)
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First question: when you say you turn the key and nothing happens, do you mean that no lights come on whatsoever? Or, do you mean the lights come on but the engine doesn't crank? Or, do you mean the lights come on, the engine cranks but will not start?

When you installed the new coolant temperature sensor, did the problem go away for a couple of days then reappear? Did you recheck the electrical connection to make sure it didn't come loose?

Do you have a VAG-COM connector? With your closest dealer 350 miles away, you really ned to make this investment. Then, you can read what the ECU thinks the coolant temperature is and see if that makes sense.

Bob

 

Hey Bob,

Sorry for the confusion...when I turn the key, yes the engine cranks and lights come on as normal.

Saying the problem went away for a couple days then reappearing isn't an accurate way to determine if the new sensor is a dud. As my problem is intermittent...i really never know when to expect it to arise again. I've gone so long as 3 days (w/ new sensor) before the problem came back. Sometimes it will happen every morning...other times it wont happen for days. And yes I did check the connection...everything looks okay.

You're right, I need to purchase a VAG-COM connector. There is a guy around here that drives an '01 S4 wagon that he's done alot to...and I'm pretty sure he's got a VAG-COM & software. Only problem is, I have no way of contacting him. I do know where he lives lol but showing up at his house and knocking on his door wouldnt be the best approach.