1979 450 SLC failed to pass emissions test, BUT ONLY BECAUSE OF ELEVATED CARBON DIOXIDE LEVELS. Any suggestions on bringing the CO2 level in line without effecting the other variables. I have been told that the car should be very hot before testing and to use premium gas. There are also some additives that are supposed to help with emissions tests.

Any suggestions?

You need to adjust the CO. The best way is by using a 4-gas emission analyzer.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Where are you located?

a 79 should not be issued for emission tests anymore. Here in Canada any car over 20 is considered an antique and does not need emission tests. This is probably because just about any american car falls completely apart before it has a chance to be 20 years old, and there is a lot of these here

xp

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1985 190E 2.3L - a constant project.

I am in Atlanta, GA. Unfortunately, 1979 is the latest year the govt requires testing. My luck and, believe me, I have fought authority many times and authority ALMOST always wins.