PCA SDR

Hi all,

I purchased a 944 recently and can't get it to pass smog for registration. Yes, I know it's the sellers responsibility. Suffice to say, it's mine now (It's a long story). Here are where things stand. I can get the car to pass at 15mph but at 25 it fails nox. If I adjust so that it passes at 25, it fails CO and HO at 15.


The car runs beautifully.
The plugs are great.
The car has a new CAT installed before I bought it. It's shiny and good looking but who knows, maybe thats the culprit?
I've replaced the 02 sensor.
I've changed the oil and filter
I've tried 91 fuel and 89.
I've tried adding alcohol.
I've tried adjusting the Fuel Quality Switch to -4 fuel. I've also tired it at -4 fuel and -4 timing. It's now back at setting 0. The car continues to run fine, but still won't pass.
I've adjusted the MAF to various setting.
The MAF is sealed tight but I don't know if its been opened.
Lastly, I've left it at a shop with a smog dyno and a mech who works at the Porsche dealership...he can't find a setting where the numbers are right either. His next step was to replace the ECU, not because he knew it would fix things, but hoped by throwing one at it, it might. I told him I could do that, button it up.

Help.

Please for the love of Zuffenhausen...help.

Mark and Kari

Mark,

I would have to see the failed VIR numbers for sure but it sounds like your "new" cat is your issue or your o2 sensor system is not working properly.
The "Other" VIR readings will tell the story.
Set the fuel quality switch to +4 fueL and -3 timing for 944 NoX issues.

Or send me a scan of your VIR and I will give you my opinion.

Hi Steve and everyone. In addition to these scans, the smog person we were using ran about 8 pretests, all of which failed either at 15 or 25 depending on the adjustments we made. As you can imagine, the numbers were all over the place depending on the adjustment. Here are pics of the official attempts.

Thanks folks.
Mark and Kari

This first is when I first went to try, no adjustments at all. You can't read it, but the CO2 is 13.6 and 13.3



The second is with the FQS set at -4 fuel and the MAF screwed all the way out to lean.



The third is with a 20% mix of alcohol and the FQS at -4 fuel and the MAF screwed to full lean and in five turns.

Mark,
You likely have multiple issues there, not just one.
Testing needs to be done to find out why you have such drastic swings in CO.
Fix that and every this else should fall in place.

You should check test history to see if this has been an ongoing issue or new.
That may give you some insight.
http://www.bar.ca.gov/pubwebquery/Vehicle/PubTstQry.aspx

It only had one fail, two days before its last pass in Aug. 2013. All the previous years it passed.

So, you think switching out the exhaust to a borrowed one with a factory CAT won't do it?

You mentioned, "Testing needs to be done to find out why you have such drastic swings in CO." Unfortunately I don't have these skills or equipment...soooo...erm... Is that something you can do...and will I need to I rob a few liquor stores or sell a kidney?

I do greatly appreciate your help thus far.

Mark

You need to fix the problem before switching exhaust.
That radical CO swing isn't a cat.
What it is doing now will just kill the cat.
1) find and fix the problem
2) drive the car after repair to try to clean the fouled cat
3) test system and see if it will fly w/o cat replacement.

Yes I can look at it if you are not is a huge hurry and I can work it in.

It can be an involved process ($$$) and I know you said you have no recourse from the seller, but you should exhaust that avenue first.
It may be a hassle, but unless you signed something stating you waived the smog requirement or bought it at auction, they are responsible.
I know... the long stories are the saddest.

Hope this situation gets resolved MB. See you Sunday?!

Thank you Steve for the advice and patience.

We tracked the issue to a ECU/DME that had a performance chip installed by Autothority Performance Engineering. A call to Sean at Autobahn resulted in a tested, stock unit. Then there was the "new cat" they'd installed. Yes, it was new, and numbered and shiny, and about six inches long...I don't think it would work beyond looking like a cat. Maybe great for racing!..A cat? sure...look there it is! We installed Paul Jr.'s factory exhaust and set the MAF at seven turns off of full rich. Though CO only made it by ONE point, we passed!

Sparky is tagged and street legal!

I must also express a HUGE thanks to Paul and Ruth, who put up with me invading them and stealing Paul for endless hours of testing and forced labor.

Cheers,
Mark