testarossaguy

My 99 A8 occasionally takes quite a bit of cranking before the engine fires up. It doesn't seem to be consistent...like that it happens under the same circumstances. It just happens "whenever". Normally the motor fires up in the first 2 seconds, but once in a while it takes maybe 4 or 5 seconds to catch. I've read that this could be a bad temp sensor? If so where is this sensor located? I checked the codes on my car yesterday and got these:
17547 01/01 (fuel trim) and 17087 01/01 (torque convertor malfunction). I cleared them and will check again after driving for a while. Are there any other areas I should check out? Thank You.

ttuling

You can read the temperature seen by the engine control module in one of its measuring blocks. Let us know if that's what it turns out to be. I'd sort of expect some other symptoms if it is, like bad running after it starts.

Also you might follow the troubleshooting procedures including taking electrical measurements for the crankshaft angle sensor (also called rpm sensor in the service manual) and camshaft position sensors. The signal from the crank angle sensor is faintest at low rpm, so if the sensor's marginal, it can delay or prevent starting, and the ECM may not log a code -- the fact that the cam position sensors still work at cranking speed isn't enough to clue it in if that it's missing the rpm sensor signal. This is the case on the 5V engine at least. Maybe the 4V is different.

Tom