Originally Posted by C.Doner

Usually the smog place will charge you half rate if you only want to do the pre-test. Maybe they will let you play with that allen screw while its hooked up to the machine. Not likely at the smog place but worth a try. Someone will though just call around and ask.

Originally Posted by C.Doner

Being a euro makes it a little more difficult. Many mechanics just dont know what to do. It is meant to be tuned without the cat.
There should be a adjuster on the fuel distributor. These are set at the factory so they should not need adjustment. I did adjust mine to ear at first myself. Then I used a old smog machine to dial the AF ratio.
You could find a smog place that does repairs as well an ask them to make adjustments. You will have to tell them what to do based on what we say here.
Enrique probably doesn't want to set the AF ratio because he does not have a exhaust analyzer. A low end smog/ repair shop will do as much for much less.
There is an small allen on top of the fuel dist. 3mm. While at idle Push it in and turn very slightly clockwise until it begins to stall. Then slowly go back until it smooths back out.
You can do this at home without the exhaust analyzer. It wont be exact though. I think if you get your idle figured out you can get it tuned enough to pass. I just looked over your 2013 test and you were only failing the 15 mph test by not much. The 25 mph test was a fail but very close. Only nox was high. That leads me to think its the CAT. My car had similar readings before I replaced it.
I would find a smog place that does repairs too. It has to be a non "smog only" station. I would tell them how to adjust the fuel mix . and ask them to check the Cat. They will use their analyzer to dial you in. It should not take more than a half hour to an hour. The trouble would be finding someone wiling to touch it.
Too bad your not up north. I could hook you up to my analyzer.
Dont loose hope thats a nice Euro. It is worth getting it running. It probably has aftermarket Cats already. New ones from an exhaust shop will run 300$ or so each.

Originally Posted by hookedon210s

In my experience the fuel mixture on CIS fuel injected engines can be set way too rich and the car will still run OK but gas mileage will be awful and the car won't pass emission tests. This makes it difficult/impossible to adjust the mixture without an exhaust gas analyzer if the emission test is strict. With that in mind, if you must adjust it yourself, the engine must be fully warm including the engine oil. With the car idling in park press down on the adjustment tower with the 3mm adjustment tool until it engages screw in the air plate and then press down slightly to deflect the air plate minimally and note if the engine speeds up or slows down. If it slows down, the mixture is too rich and if it speeds up significantly and smooths out the mixture is too lean. Ideally, you will adjust from the lean side towards the rich side to get to the correct mixture. You will get to about as good as you can by ear when the engine idles fairly smoothly (no misfire), a slight push on the air plate screw will cause a slight increase in idle rate (about 50 rpm), your exhaust does not smell of catalyst odor and there is no pop back in the exhaust which would indicate a misfire. Mark

Originally Posted by hookedon210s

Clockwise is richer, counterclockwise is leaner. First you have to find and fix your vacuum leaks or you are wasting your time. Unless you can hear a vacuum leak from the hoses buried at the throttle body don't worry about them for now. The large idle air hoses looked suspect in your pictures and the injector seals and supplementary air hoses that connect to the fuel injector holders also tend to get hard and cracked. Diagnose and repair the leaks and report back.

Originally Posted by Skippy

If you can't find anyone closer, I'll give a shameless plug to Sporthaus Motorcars in Reno. They have an exhaust analyzer and know how to use it. They specialize more in older Porsche and Jaguar along with newer Audi, but handle emission issues on older German cars all the time. The owner John is quite knowledgeable about old Bosch fuel injection.

In the interest of full disclosure, I used to work there.

Originally Posted by hookedon210s

if you must adjust it yourself, the engine must be fully warm including the engine oil. With the car idling in park press down on the adjustment tower with the 3mm adjustment tool until it engages screw in the air plate and then press down slightly to deflect the air plate minimally and note if the engine speeds up or slows down. If it slows down, the mixture is too rich and if it speeds up significantly and smooths out the mixture is too lean. Ideally, you will adjust from the lean side towards the rich side to get to the correct mixture. You will get to about as good as you can by ear when the engine idles fairly smoothly (no misfire), a slight push on the air plate screw will cause a slight increase in idle rate (about 50 rpm), your exhaust does not smell of catalyst odor and there is no pop back in the exhaust which would indicate a misfire. Mark