Rough start when its cold? Help
02-10-2004, 09:33 AM
#1
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Rough start when its cold? Help
When I start my A6 and the temp is below 15 degrees. I have to wait AT LEAST 1-2 minutes before I can take off. The car will idle, then sputter for a few moments, then idle again. Then after a few minutes its fine. Any thoughts? I use 93 octane gas. 2.7t 2000 A6
02-10-2004, 10:03 AM
#3
Sounds like 02 sensor or cold start valve.
The 02 sensor needs to be hot to work correctly, so when a car is cold, it usually has a special warm-up program that bypasses the 02 sensor. This usually takes 30 seconds or so, and then the 02 sensor should take over. It sounds like the hand-off to the 02 sensor is not smooth - meaning the 02 sensor may not be dead, but on it's way out. Check the connector too, just in case it's marginal.
Also, I'm not sure exactly how the 2.7t is laid out, but most cars have a cold start valve that gives the car a little extra fuel in the initial start. If that's not working correctly, you can have stumbling and reluctance to start. Often the idle will be a tad high (higher than normal start idle) and stay a bit higher than it should be.
Also, I'm not sure exactly how the 2.7t is laid out, but most cars have a cold start valve that gives the car a little extra fuel in the initial start. If that's not working correctly, you can have stumbling and reluctance to start. Often the idle will be a tad high (higher than normal start idle) and stay a bit higher than it should be.
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