So...barely 3 months on and the CEL came back. Same P0410 and P1411.
To be fair, I only drove the car 4 or 5 times in that period. The good news is that my change over valve is still doing just fine. The bad news is that I had to dig deeper into the SAI.
I tested vacuum before and after the electronic change over valve and got 16" of water on both sides...vacuum good, electronic change over valve good.
Used the Durametric to activate the air pump and electronic change over valve at idle with the change over valve disconnected from the line that goes to the check valve. Good airflow.
Crap. I have to remove the alternator and pull the check valve.
Well, I did. It was a bit rough. The top half of the upper fitting had completely deteriorated and the bits of rust scale and left over fitting were plugging the valve.
The dents and scrapes are from me beating the crap out of it.
A new OEM valve ranges from $80-$150. Seriously?
It's a bit of stamped sheet metal and a diaphragm.
Nippondenso 99311325003 Porsche SAI check valve ~$100+:
I ran a google image search and found one that looks the same, right down to the little nubs on the side.
Guess what? It's s $20 1993 Mercedes 300e part. Same as the change over valve. Imagine that.
MTC 3095 Mercedes SAI check valve ~$20:
I ordered one and will report back next week when it arrives, but I'm 95% sure that is exactly the same as the "Porsche" part.