A4 3.2 Cabriolet Misfiring and emissions check light (potential cam chain stretch?)

[Craig Bull]

Hello,

I'm a new member here and was wondering if anyone has had any similar issues to me and might be able to help?

My A4 3.2 began to sound really loud on start up about two weeks ago and started to feel quite sluggish to drive. The noise was originally at start up and then died out when it began to idle, however since then the emissions light has come on (flashing) and the noise has been joined by a lot of shaking/rattling and continues all the time. I have used an OBD reader and found the following codes:

• P0366 - Camshaft Position Sensor B Circuit Range/Performance Bank 1
• P0301 - Cylinder 1 Misfire Detected
• P0302 - Cylinder 2 Misfire Detected
• P0303 - Cylinder 3 Misfire Detected

I have switched the camshaft sensors and the code detected did not change. This leads me to believe it is not a problem with the camshaft sensors directly.

A friend of mine said it sounds like it could be cam chain stretch so he ran a test using VCDS software. We looked at Group 093 which is the camshaft adjustment values and you can see in the image that bank 1 exhaust is 31.9KW compared to the rest which are no greater than 6KW. I read somewhere that this figure should not exceed 8, and over 12 would generally mean it is skipping a tooth.

Has anyone experienced any of these issues? or have any advice they can give me? Next step will be to take it to a garage and get them to run diagnostics to get a definitive diagnosis, and go from there. I know that if the cam chain needs replacing the cost will be astronomical so hoping it could be something else.

Thanks,
Craig

 

[AlpineCab]

I've got a 3.2 and experienced more or less same probs.

Before you go to the garage and talk chains, there are couple of things you could look at

- the camshaft position sensors
- the camshaft actuators

Both of them are fitted 4-off on the engine ie one sensor and one actuater per cam, so you could work out which cam is showing the fault or just do the lot. Parts can be obtained from dealer, and are easy to fit. Make sure you get the rubber seals too.

IIRC the sensors are service items albeit 60,000 km or something like that, and there was a recall at some stage on the actuators, though I may be mistaken, but in any case that's why I changed them all over the space of 12 months or so.

Also change the oil frequently and use the best, as the oil pressure does need to be good to activate the cams. I use 0-30 despite having around 300,000 km and all runs like clockwork (touchwood) with practically all the rattle that used to be there now eliminated - it sounded like a black-cab before I did all the above. I've always resisted using engine cleaners and oil treatments and such before oil changes as I've seen too many horor postings on other parts of the forum.

 

[neilA4]

Swap the cam sensors round and see if the problem moves with the sensor.

If not you probably need to do the top chain tensioner which can be done engine in apparently