swrt83

Hey all

I noticed yesterday that I had a little bit of a rattle in the engine after revving in the 5000-6000 rpm range. Just heard it, didn't really feel anything. I know very little about engines other than some basic stuff taught at school (engineering courses). Should I have cause for concern that I have a misfire or could something be loose in the exhaust? I hardly ever drive her hard, shifting usually about 3000 rpm. Any comments or suggestions would be great, thanks!

-2004 B6 3.0

swrt83

Any help would be great - it was from a dead stop.. had to gas it hard to merge with traffic and heard it while in first

4Rings::G2 boosted::

That would most likely be pinging and that means your mixture (or less likely timing) is off and needs to be addressed asap.

It could also be one of your tensioners going bad, or possibly a fan clutch or any of the accessories (a/c, alternator, etc.)

swrt83

I wish I could remember the noise more distinctly, but it was more than 3 days ago now. It might have sounded like marbles or something not quite as loud.. Can you explain what pinging is all about? Or what it would sound like if it was just a tensioner? I appreciate all your help..

4Rings::G2 boosted::

pinging is premature detonation of the a/f mixture in the cylinders due to (a) incorrect timing, which on most newer cars including ours is prevented by knock sensors or (b) high temperatures due to lean fuel mixture. Since pinging is very jarring to the engine internals and usually is accompanied by very high burn temps, it is very dangerous and can destroy an engine fairly quickly. If you think that's what's going on, get a vag and check your trim levels, chances are they are skewed due to a problem with your mixture. And whatever you do don't push the engine hard until the pinging is addressed.

swrt83

For instance, rough idle or excessive noise? What else can I look or listen for? I don't abuse the car in any way shape or form, and the most 'work' it really gets is merging onto the crazy highways.. and even then i didn't really notice any odd rattling (usually in 3rd or 4th gear).

I guess I'd like to know how I can rule out ping
(either way I'm gonna need to have it looked at soon)

4Rings::G2 boosted::

anyone who's heard pinging will pick it up immidiately. Also, hook up a vag and check your trim levels, if they are n close to 0 that'll be a good sign something is off.

swrt83

I'll have to update you when I find out what it is. Thanks again for all your help!

swrt83

If I check my trim levels, the car should be running, correct? This is all still pretty new to me so I would appreciate if you could explain this just a bit. Or if anyone else knows about this please give me a hand. Thanks!

4Rings::G2 boosted::

so just check them without the engine running and post the results. Just don't reset the error codes beforehand, once the error codes are reset so are the trims and then it'll take a bit of driving to get them to adjust again.