CA now requires a visual inspection along with the test machine. Last summer I couldn't find one, who wouldn't look. So if they find all the SAI junk missing, it could be a problem.

The Visual Test is one of the few advantages we have with the Boxster & Smog Tests. Access is so awful ! The Tech is very unlikely to remove the engine cover. If you think this is a risk, just leave the SAI components in place.Really , a Smog Tech is not allowed to unbolt anything on your car. The Referee is a different story.
The DAD system is so effective at finding tampering that the Techs I know don't make much effort with Visuals. The DAD is far more effective because it compares the stock ECU program to your actual. And DAD keep loading more & more data into their system.They are more focused on newer, higher volume cars and known tampering targets (Ricers !,Mustangs,big Mopars,trucks) ,so we may get away with being overlooked ?

Here in Ontario .We used to have a dynamometer test with a rolling road run at about 25 mph and also a sniffer at idle Today the test is less involved with a scan of the ecm looking for fault codes and readiness monitors I don,t recall if they still use the dyno for certain years or not as I was not present when mine was inspected. It did pass though with both cats in place but ROW tuning because I was going to add headers but haven,t as yet.

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. :)

http://i875.photobucket.com/albums/a...9EF57E17AD.jpg

A new OEM valve ranges from $80-$150. Seriously?
It's a bit of stamped sheet metal and a diaphragm. :rolleyes:

Nippondenso 99311325003 Porsche SAI check valve ~$100+:

http://i875.photobucket.com/albums/a...76F9C36909.png

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:

http://i875.photobucket.com/albums/a...BEFB31DDE5.png

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.

The ROW flash is looking like a much better option. Cheaper, simpler, and adds lightness.

There is a far more compelling case than that for some of us. We can not fix the SAI system. Some very competent Forum members have performed every imaginable test yet fail to find a fault. If you can't find the fault, you can't eliminate the SAI fault codes .If the SAI fault code is present, you can't pass the Smog test so you can't get a registration sticker. If you run out of time on your old sticker you are in real trouble.
Ultimately there is no alternative to the ROW flash until someone figures out a reliable way to fix the SAI system.
Sometimes it is easy to fix the SAI but not always !

If the problem comes up again after replacing the check valve, I'm just going to remove the whole system.

I've just built a circuit that fools the DME during cold starts, so no ROW flash needed. The circuit is triggered by the air pump relay and just feeds a signal to the DME indicating that the required emission conditions have been met.
That will be the end of it and no pricey flash. ;)

My 99 had the same problem. My indie determined it was the valve. I remember getting a deal on one online. I also remember it was a SOB to get at.Every so often it will throw those two codes. I clear them and gone.

Mr. Particleweave,
I agree about the ROW reflash cost for an SAI solution. The ROW reflash includes several other features(see ECU Doctors for details) but they are not useful to me. I just want to pass Smog so I can be 'legal' and get a sticker.
Your brilliant wiring modification seems excellent .One advantage is that since it is triggered by an existing relay ,it is easily reversible if some new Smog Law detects the hack.
If you would like a guinea pig to volunteer to use your modification and report back - please PM me .

Particle wave - I am interested in buying something like this if you produce it.

I'm going to go ahead and order the components to make 5-10, but I want to run this one on my car for a good 3-4 weeks to give it a good shakedown and address any bugs that might pop up. I'll try to drive everyday so it cycles the SAI as much as possible and monitor emissions components on the Durametric.

If everything looks good, we can go from there. Sound good?

I don't foresee any issues at all and I would think even California guys could get away with it as the system should show ready and the only time emissions would be high is at cold start. If you drive your car to the emissions check, it shouldn't trigger the SAI when they test it, but that depends on how long it sits before they get to it.

Sounds great!

"I would think even California guys could get away with it as the system should show ready "
To overcome the problem of the Visual Inspection done by the Test-Only Smog Stations - just leave the SAI Pump in place but non-functional.
I have a particularly rigorous Test Only appointment soon so will report back on how determined they are to actually do a Visual Inspection on a stock Boxster.

Just a follow up on the MTC 3095: I received it yesterday and can confirm that it is the exact same valve as the Porsche part. :)

Thanks for closing that loop - great parts sleuthing - a valuable alternative to save other Forum members some $ and grief !
How goes your related SAI test project ?
I confess a personal interest because I have no DTC's but can't get the Secondary Air system to show Readiness

Everything looks great so far...showing "ready" and no hiccups. :)
I'll have the rest of the components to build the first 5 by next Wednesday, so will get those built by next weekend.
I'd like to run the prototype in my car for another week after that, just to be sure. ;)

Gelbster, have you tried the SAI test on cold start while you rev at constant 2500 to 3000 RPM? I fought this issue where everything went ready except SAI and was pulling my hair as I was running out of remedies. Alas, I found a thread where one owner mentioned immediately reving steady state during the first 90 seconds WITHOUT driving the car! I had tallied hundreds of miles without it going ready and within first 90 secs in my garage bingo.

I took my car in for the test a few months ago and they did not run it on Dyno and he did not do a visual.

Lap,
Thank you for the suggestion.
That 90 second period is exactly when the SAI pump is operating so there may be some logic there. worth a try. Thanks for the suggestion.

One detail to mention. Porsche changed some components of this system for post-99 cars - namely the E-Gas cars. Two valves ,including the check valve and the SAI valve were combined into one new part called a "Shut Off Valve" 997 113 249 90 - number 15 in the Auto Atlanta drawing linked below:
http://ffff18261f171e868c00-299409308e1e9f6b30fe104b978eef3b.r43.cf2.rackcdn.c om/108-06.gif

There is still the same Vacuum Tank that develops hairline cracks at it's base and the electrically operated change over valve.
So Particleweave how is your Test going?

Hey guys, Sorry to bring up this old post.

I have the same problem with the SAI system. Both P1410 and 1411 codes are on. The OEM check valve and change over valves are expensive.

Particlewave, I know you confirmed the Mercedes MTC3095 was a perfect fit for the check value in 986. Can you confirm if the mercedes part for the change over value is also a good fit? The part looks different. How did you make it fit? Do you have pictures you can share?
NEW MERCEDES AIR VALVE 380SLC 380SEL 380SL 380SEC 420SEL 190E OE # 000-140-77-60 | eBay


Also, any update on your little hack on fooling the DME during cold starts? do you have it up and running?