Rafi-
I went through this same thing when I purchased my '95 E320 wagon. You are already getting WAY too scientific. I think you need to ask yourself a few questions.
1. Does your car run well? Or are there performance problems?
2. Are your fuel milage numbers in an acceptable range for your model/engine type?
3. Are you burning oil?
If, in fact, your car runs well and the milage is reasonable, just get a bottle of the CRC "guaranteed to pass emissions" formula. I also failed NJ inspection by .02, and after using that product as directed, barely made a blip on the emissions tester. I would not suggest to use it long term. However, once your car has passed inspection, you'll have 2 years to figure out why you failed. Also, the bottle of CRC crap is 10 bucks, so its worth a try. YMMV, but it worked for me!

John
1985 300D 265K
1995 E320 145K

Due to the less than 100% efficiency of the internal combustion engine and related componants, a vehicles emissions can vary as much as 20%, from one test to the next, this variance increases with milage.

And for fuel additives, think, if they really worked, nobody would fail.

If he missed the HC cut-off point by 2 ppm , he may be well advised to try the " Miracle in-a-can " for $ 10.00.

__________________
2007 C 230 Sport.

I am happy to put a closure to my saga. It finally passed the emission test today at the limit.

test results today (static, not dyno)
comp___reading___limit
NOx _____??______??
HC______100_____100
CO%____0.33____0.50
CO2%___13.9_____??
O2_______??______??
RPM_____2571

I complained about the arbitrary limits to HC 100 and they agreed that NJ and CA are the strictest states.

What I did or what I did not do?
Changed spark plugs, air filter, O2 sensor and used CRC guaranteed to pass emissions. While replacing all these items I discovered that the hose from crankcase to the intake manifold was split and sucking air so I changed that. I did not do any of mods I was entertaining in this thread, since the ECU will compensate, since it compensated for the air leak into the intake after the MAS.

I checked the duty cycle and now it averages ~ 50 % in closed loop while previously it hovered around 54% I would suspect beacuse of the air leak. I do not think I made much difference in the car it was fine before and it is fine now. I basically sacrificed ~200 at the state's altar. 2 PPM diference is nothing since I do not know the reproducibilty of the testing that is done.

Well now I have some spare good parts and 2 years.

Good for you, glad you passed.
When you're talking 2 ppm, that is really " splitting hair ".
Chances are, if the test was run again, within minutes, you could have - 2ppm, or + 2 ppm.
I stand by any of my previous statements.
IT'S A RIP-OFF.

__________________
2007 C 230 Sport.

manny - you are preaching to the congregation. It is rip-off. The same rules do not apply to everyone. MD and NC among many have 220 PPM limit whereas FL does not even have emission testing anymore.

Rafi

I just looked at the limits here in Ontario:

Idle:
CO = 0.70 %, HC = 150 ppm

2500 rpm:
CO = 0.70 %, HC = 150 ppm.

Somebody needs to get their sh... together and have a universal standard.
Unless your CO & HC is different than ours.

__________________
2007 C 230 Sport.