LexusLSguy

I was contemplating tackling a few extra items on my 14 3.0 Something I used to do rather easily on my previous vechiles. This is cleaning the throttle body and MAF sensor. Have any of you guys tackled this on your Audi? It looks fairly easy to access. How about the PCV valve? Something that should be changed? I'm all about preventive maintenance.

Also, does the A8 have an smog sensor that switches to recirculate when carbon monoxide is detected? I really loved this feature on my previous Lexus vechicles but I don't see an option for this.

Jack88

The PCV valve on this car is best left alone unless it fails. I'm fairly sure the one on the 3.0t is among the overly complex units Audi has liked to use, but otherwise feel free to clean stuff up. I can't tell you how easy those are to remove, but they appear simple enough to my eye. The smog sensor is a new one on me, it's not a feature I'm familiar with on any car.

LexusLSguy

Hmmm, that's too bad Audi does not have this. Really a fantastic feature to help prevent nasty fumes from entering the cabin. Just a simple sensor that was mounted on the LS right in front of the radiator and it would automatically switch to recirculate if it detected smog. You could set the sensitivity as well. Even my old 2004 LS430 had it.

I did search for pcv valve on my car and it does look way more complicated then necessary. Got to love German over engineering. Something I am getting use to. I just ordered some new tools to do some of the basics. I swear, they really don't want the average owner to do much on these cars... lol

MP4.2+6.0

Many blown motors--S/C or turbo--don't use an MAF. They use some other sensors, but they aren't really in the middle of the airstream like an MAF is. See a few pics from 3.0T SSP that would help orient you.

Sort of slow to load, but here is that source document from when Audi first released the 3.0T. D4 version perhaps somewhat tweaked, but they usually only do these to train the techs when a new motor is first released: http://www.vaglinks.com/vaglinks_com...FSI_Engine.pdf

MP4.2+6.0

Audi doesn't spend a lot of air time on this in the owners manual, but it is incorporated in vehicle from Audi's documentation. Part of the control strategy for the HVAC. See first image below from the D4 intro publication. Only indirectly mentioned because they were more focused on the humidity sensor for whatever reason, but you can see the air quality sensor there too. For Audi it is built into the air ducting instead of up in front of radiator. The outside air tmp. sensor is up there. I also pasted in text back to the D3 intro when they flagged the air quality sensor--the bigger type that is from a separate doc't even if it all looks merged in the image below. I forgot it also supposedly cuts in for windshield wiper spraying, though on mine with the winter mix in now it isn't fast enough for me not to get a whiff of the methanol.

You can also change the recirc. sensitivity if you poke around in the settings you see via the MMI display under Car/AC. See pic below.

LexusLSguy

Thanks MP, as usual you are a wealth of information. I noticed this in MMI as well but not sure how well it actually works. I also get whiff when using the windshield wipers and I have yet to notice the system automatically switch because of smog. I will set the sensitivity to max and test again. The reason I mentioned this is because on the Lexus you could easily remove it and open up the sensor for cleaning as it would become full of gunk over the years and the sensitivity would be compromised. Part of the tune up process for many. By the way, I have my VCDS unit on order. Can't wait.

MP4.2+6.0

Thanks. If you shift to DIY, also plan to change out HVAC filter yourself. Easy. I think service interval is every two years/every other time, so I do those in the alternate years even on AudiCare. More so if sensitive to air stuff like some in my family are. Charcoal embedded filter too, which obviously can't really go two years with good effectiveness for odors. Cheapest source is still internet discount dealer for me; a little less than the OES type branded ones like Mann and others. Maybe buy one now, pull yours and make sure it was done. Or, pul first to check. If so, fine and hold it for next year. If not swap out...and have yet another dealer discussion...

While at it, check wiper blades too to see if really in top shape. Dealers don't do those under AudiCare or warranty except for $. I'm finicky on those and do way before they fall apart. Giving my 2015 until about next season. Another easy web dealer part with no rush.

LexusLSguy

Funny you mention this, the first thing I did was order a cabin filter off Amazon. When I pulled out the current filter it was still in great shape. Their only $15 on Amazon. Very easy to do as you mentioned. I also replaced the engine air filter with a K&N filter.

I ran a bottle of Dura Lube fuel system cleaner when I first got the car. A few tanks later I put in a bottle of the Berryman B12 after reading good things about it with a Costco 93 octane fuel up. She is idling incredibly smooth now.

MP4.2+6.0

Make sure filter you got is the carbon one. There are usually two flavors and the non carbon one is often half the price. Carbon ones have a characteristic gray pall to the pleats. Yes, fuel additives periodically; I use Techron. Fuel filter in next few years (call it 75K) is cheap maintenance too, and not on any of the service lists. Not a fan of K&N's (and did used to run them), but another one of those religion and politics and subjects like brake pads, tires and so on. At least 3.0T doesn't have an MAF which is where the insidious performance subtract occurs.

LexusLSguy

I hear you. I have never had any issue with K&N but I know some have. Usually problems can come from users over-oiling them and fouling the MAF.

This is one I purchased. I have used them in the past with good success.