Car has 115K miles.
Does the 1989 190e 2.6 has a EGR valve? didn't see anything coming back from the exhaust like the 93, 300E I had once.

15MPH test RPM 1911
%CO 14.4
%O2 0.0
HC ppm = max 114 Average 31 measured 169 failed
CO % = max 0.73 Average 0.10 measured 0.84 failed
NO ppm = max 785 Average 237 measured 726 pass

25MPH test RPM 1893
%CO 14.3
%O2 0.0
HC ppm = max 88 Average 20 measured 158 failed
CO % = max 0.61 Average 0.09 measured 0.94 failed
NO ppm = max 724 Average 199 measured 677 pass

Since the failed test I changed the oil, air filter, checked spark plugs, filled up with fresh 91 octane, any other reccomendations before I take it back for the re-test.
I read the posts about prior conditioning of the motor to make the cat run hot.
Anything that the MB gurus can come up with that could help.

Thanks.

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Thanks, Juan

I'm no pro - but I do have a 93 = 190= 2.6 that is having some smog issues. A wiser member than I, suggested that the first thing I should, was to sure the secondary ignition circuit ( coil ,thru the Cap and down to the plugs) was perfect.

That made a huge difference, but still did not allow me to pass.... I'll do the O2 sensor next. With the M103 motor in a W201, be sure you heat it all up well before the test, that is, don't go in cold...try to have at least 20-30 mins of running prior to the test Your Cat from is pretty far from your exhaust manifold, the heat will help with a cleaner burn, and hopefully better emissions.

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1993 190E 2.6 135k
1989 Ford Thunderbird SC 5 Spd 79K

My 89 2.6 passed Va smog a year ago changed plugs,wires,rotor,cap,air filter,oil and oil filter.

Thanks, I have a feeling that part of the failed smog results were the cause of going cold at it.
The shop the previous owner took it to is only 5 minutes away from where the car was parked, he didn't drive it very far at all.
I also do not think that the shop did anything to help because they quoted him 200.00 to replace the CE light bulb. I chaged the OVP 10 amp that was busted and the light is normal.They also quoted him 150.00 to make adjustments to the car for it to pass.

I will warm it up good before I re-test and then I will know for sure if I have to change anything.

I'll post results after I re-test.

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Thanks, Juan

Make sure you have all NEW filters, air, oil, and the air pump filter in the air cleaner. Also new Distributor Cap, rotor, plug wires and plugs. Look at your sticker on the front rad support, that is the things they check by sight. If they don't check the air cleaner(for Filter being there) take it out for the test. You might want to replace the O2 sensor also. Then do the warm up thing(30 miles to get it nice and hot).
Buy a new gas cap. Take it to a reputable Terst only station if you can. All they can do is test, no repairs.
Yes it does cost a bit but every two years they probably need changed anyway.

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1986 Euro 500SEC "RUF" 9:1CR, "Rose"
1985 Euro 500SEC Cabriolet AMG Widebody
1982 Euro 500SEL "Blue"
2001 Texas Heeler (Aussie/Queensland X) "Sulphie",
2012 Queensland Red Heeler "Squeak"
Best dogs I've ever had.

Had a CA smog re-test done today, after it failed last time about a month ago, the previous owner had the car parked for 2 years and took it in pretty cold to test, the test place he took it was about 2 miles away and the results were terrible as you can see at the posts 1st paragraph.

So what I did was changed the oil, put fresh supreme gas 91 Oct. run 2 tanks cleaned the air filter and retested it.
These are the results now:

15MPH RPM 1514 %CO2 15.1 %O2 0.2 HCppm 57 CO% 0.31 NOppm 781
MAX 785

25MPH RPM 1476 %CO2 15.1 %O2 0.1 HC ppm 57 CO% 0.32 NOppm 461

The car passed but the NOppm at 15 MPH is 4 numbers below the max of 785,
How do you get lower NO numbers?

Thanks for the input I was able to pass the test without doing major repairs.

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Thanks, Juan

I had a 1993 300E (3.2) "E320" for about six years, and it barely passed every time I had it smogged.

My take on these cars is that they just run at a level where they barely pass right under the limit.

My only suggestion is to go in to a test with a very hot cat and hope for the best.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I had the same issue of a smog inspection failure on my 190e 2.6L. In additon to the things that you already did, I also changed my spark plugs, used "Guaranteed To Pass" additive bought from a local automotive store, and ran my car hot on idle while I waited my turn. It made such a difference on the results!

The car passed the test, maybe it was running to hot from me keeping it at 2500rpm before the test, the HC was lowered but the NOx camw back on the border. I won't worry for another two years.

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Thanks, Juan