BrianAudiA6

I'm happy to post pictures but the BPV's don't seem to come apart easily to show the internal components. I'd like to take the "cap" off the end to take out the diaphram and spring but can't figure out how to get it off without breaking it. Any suggestions?

BrianAudiA6

So I got ripped off for $400 for two stock BPV's replaced by the lousy dealer. Drove it home and as I pulled into the driveway the CEL came on! Ughhhhhhhh! Scanned it with VAG and found that two of my codes are back: Fuel Trim Bank 1 and 2 reading System too lean. These are the ones that I understood can likely indicate a bad MAF. Again, I had somewhat confirmed that as well by reading the Group 002 airflow mass in g/s at full-throttle and only got about 137 g/s at 6500RPMs and was expecting to see 200 g/s given the reading should be about 200 (250HP x 0.8 = 200) which I read in another thread.

One thing I didn't mention is that in addition to the two above lean codes, I also had a 17539 Oxygen (Lambda) Sensor: B2 S1: Internal Resistance too High and 18030 Engine Coolant Temp Signal Range/perf code. My temp gauge was intermittantly not functioning and the dealer also replaced the temp sensor (which looks like was only a $8.11 part and couldn't have taken long to plug in). Do you think that the 17539 code was why they diagnosed the bad BPV's?? Note that with the new BPV's and temp sensor, I'm now only getting the two lean codes which I would conclude point to a bad MAF? Any thoughts?
Thanks.

BrianAudiA6

I can't believe how easy it looks (instructions from awe-tuning.ocm) to replace the BPV's! Doesn't look much harder than changing an air filter. I just checked it out on my car and at least the dealer used screw-type hose clamps. Pisses me off that I could have spent the money on some good valves and done it myself and still got away cheaper (assumeing that I even needed them!). Thanks for making me feel even worse now...

schwa

I almost made the same mistake. I told them it was ok to replace mine, and then thought better of it and called them right back. They wanted to charge $100 for the two valves, and $175 for labor. $175 for labor? Trust me it was just as easy as the awe-tuning instructions say. Anymore, if the dealer asks me if I want them to do something, I tell them I will get back to them, and research it first.

BrianAudiA6

Here are the pics. I had to crack open the cover to get it apart but did so very carefully so that I didn't damage the diaphram. You can see that both were torn. One was much worse and you could tell because there was oil coating covering the inside of the diaphram (where the spring is) which should be completely sealed tight. Also, I "tested" them before taking the cover off by pressing in the spring with one finger and then using my other finger to seal off the small nipple opening and then released the spring. My understanding is that sealing off the nipple when the spring is compressed should cause the valve to stay in the open (spring pushed in) position by itself and that did not happen. The spring just returned to it's original position. Also, you could easily blow on the nipple opening and the air would freely pass out the other opening which means it was passing through the torn diaphram, I believe.

So looks like both were shot...not sure why I didn't see worse performance and am not noticing much improvement but haven't driven it much since the new BPVs were installed. But since I also may have a bad MAF, that may be inhibiting the performance as well. I'm going to push the car a bit and see if I can notice improvement between shifts in the turbo due to the new BPV's and will report findings.

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BrianAudiA6

Good advice...lesson learned!

BrianAudiA6

Spoke to the dealer and told her the CEL was back on and it had to be my MAF. Glad that I got her to agree when they did the BPV's that if the CEL came back on, she would have them replace the MAF and not charge me the $50 diagnostic fee. So brought it in and they replace the MAF at no charge in one hour. She impled that the bad BPV's had caused the MAF to go bad. Not sure if that is a possibility but I do know for a fact that the BPV's were bad (diaphrams were ripped per the pictures I posted). Anyway, the measuring blocks are now reading only single digit lambda reading (and are now actully adjusting for a slightly rich mixture where before they were going out of limits adjusting for lean mix which was what was throwing the CEL.). I also did a WOT test in 2nd and read the mass flow readings (g/s) and they were much improved (about 184 g/s at 6400RPMs. With the bad MAF I was only getting about 137 g/s). Better, but was expecting closer to the specified 200 g/s.