I've noticed that a few times lately (last couple of weeks) I get a cloud of dark gray/black smoke from my exhaust when I start the car. It doesn't persist for longer than a few seconds, and doesn't happen every time I start the car. What does this mean? Should I be concerned?

 

does it make a ticking noise when its cold? could just be a bad lifter...my audi does this...i know its the lifter and its not really a concern to me. but it sounds like it could be a lifter or another valvetrain component.

 

i get a lifter noise if i let it sit for a day or 2. no smoke though, its burning up a little ( 165,000 ) and its been tappin since i bought it 2 and a half years ago.

 

VQ's don't have "lifters" in the traditional sense, they have bucket tappets. But anyway, sounds like your running rich at startup. Does it only happen when the engine is cold? Warm start too?

 

Just cold starts. I'm not sure if it ticks when sitting, I don't hang around after I get out very often. I get a clicking noise when the engine is running (to the speed of the engine) but I don't think that's what you're talking about. I'll just figure it's an old car thing (going on 171k miles).

 

yep, i also have noticed the tapping getting louder. i'm at 165,000 and change my oil and add bg treatment from the dealer to help with the tapping. really not much else you can do, just change oil a little earlier than the recommended 3,700, i use the partially synthetic oil from dealer and thats what they put on the sticker. i change evey 2,750 miles to be on the safe side.

 

Since no Over head cam engine uses lifters thats not really your culprit. I would say if anything with high mileage engines its excessive carbon build up throughout the engine, Nothing to worry about just run some engine cleaner through every once in a while to keep the carbon from getting out of control

 

Actually any OHC engine that uses rocker arms/followers has a lifter. It just so happens that the VQ uses a direct acting shim-over-bucket design and is absent of rocker arms and lifters.
Carbon buildup where exactly? Don't really see how that would cause any sort of ticking.

 

Age of the motor has nothing to do with it. These engines will purr well into the 200k range with proper maintenance.

Now when you say ticking, is it sort of a rattling noise, or is a cyclic tick that gets more frequent with higher engine revolutions?

 

The latter. It definitely goes with rpm. I only hear it with the windows down when the car is not driving (otherwise the ambient noise is too loud). I've heard it could be the timing chain tensioner or something. I dunno.