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Old 03-03-2005, 09:43 PM
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Join Date: Mar 2003
Location: Southern California
Posts: 2,249
Successful CA ASM emission test (KE fuel system)

Data reported: 02,%; HC, ppm; CO,%; NOx, ppm. The three numbers are Max Allowable/Average (for the 1988-1993 year group)/Measured . There is no limit or average for O2. It's a diagnositic tool. (BTW, one ppm equals .0001 percent. The report reads out constituent gases in the units reported to keep from having too many zeros before of after the signficant digits.)

15 MPH (1626 RPM - 2nd gear) 0.0 ; 116/31/73 ; 0.74/0.10/0.12 ; 791/237/21

25 MPH (1657 RPM - 3rd gear) 0.0 ; 091/20/47 ; 0.62/0.09/0.13 ; 730/199/20

Previous test (2003)

15 MPH (1657 RPM - 2nd gear) 0.1 ;116/31/113 ; 0.74/0.10/0.36 ; 791/237/261

25 MPH (2665 - 2nd gear) 0.0 ; 91/20/58 ; 0.62/0.09/0.18 ; 730/199/188

I was first in line behind a car in bay one (of three) at Auto Check Inc #7 - a drive through "test only" inspection station in Manhattan Beach and waited about 5-10 minutes keeping the engine at 1500-2000, and the engine was thoroughly warmed up when I arrived (idle oil pressure 1.5 bar). The temp gage climbed to 100, which tightened up the fan clutch, and by the time it got into the bay, the electrics were cycling. The outside temp was mid sixties with partly cloudy skies.

A couple of days ago I ran complete diagnostics on the lamda system (which includes the O2 sensor, which is original) and everything was nominal. I installed a new set of Bosch H9DC plugs. The old plugs only have 15K miles, but a fair amount of deposit buildup. Unfortunately, much of my driving is around town - fairly short trips - but I try to give her an "Italian tuneup" whenever opportunties arise!

HC is still high, and I attribute it to quench area or uneven fuel distribution of the KE injection system - or maybe a combination of both - both of which are design issues and cannot be "fixed".

Note that the zero percent 02 on both tests indicates that the converter was operating at maximum oxidation efficiency, so there is really no way to significantly lower HC or CO any farther. The fact that essentially all the oxygen was used in the 15 MPH test indicates that the converter was hot enough at the start of the test. Often, a high HC count at 15 MPH is accompanied by a tenth or two percent O2 and this means the converter is not hot enough to achieve maximum oxidation efficiency, which can cause a test failure by exceeding the HC limit The converter will cool down with too much idling or (heaven forbid) shutting down the engine prior to the test. Proper "conditioning" as stated above should help you avoid this pitfall.

The test tech was a good guy who was blown away by the condition of my car, and he treated it with great respect. I hope he's still there in two years!

Some additional insight on how to get your KE-equipped Merc through emission tests is at:

M103 Emission Test Insight

Also see 87 300E Fails Ca Smog for a discussion on ignition system issues/problems that can cause misfires, whilch can result in high HC readings, especially if part of your emission test protocol includes an idle speed test. [added 7/28/05]

The following site explains how to check the lambda system duty cycle"

The following two sites have Mercedes Benz service procedures

One other note. The "reason for test" is stated as "1.9Random Sample" This is a new one to me, and I did not get what I consider to be a satisfactory explanation from the test station people. This was the normal bienniel test, and the reason is usually "high emitter profile", and I am directed to a test only station. If anyone knows what this "reason for test" means, let us know. I may have to query the BAR for an explanation. If past experience is any guide I will probably have to contact my state senator's office for help in order to get a lucid response from the BAR.


Last edited by Duke2.6; 07-29-2005 at 07:45 PM.
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Old 03-03-2005, 10:02 PM
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Join Date: Feb 2003
Location: Ontario, Canada
Posts: 3,160
Nice numbers !
Can't see how you could do any better.
2007 C 230 Sport.
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Old 03-04-2005, 12:28 AM
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Join Date: Feb 2005
Location: Santa Ana, Ca
Posts: 10
According to the bar website:

Two Percent Randomly Selected - As required by State law, two percent of the vehicles in the Enhanced Areas are also directed to Test-Only stations for their Smog Checks. These vehicles are selected randomly to evaluate the overall effectiveness of the Smog Check Program.
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Old 03-04-2005, 01:18 AM
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Join Date: Mar 2003
Location: Southern California
Posts: 2,249
Thanks for that link! I think I've read it before, but the "1.9" didn't register.

I must have been selected as part of the 2 percent random for "test only". If I hadn't been caught in that "dragnet" I would have been directed to test only due to "high emitter profile".

Perhaps the BAR uses the two percent random sample for some detailed analysis. In any event, the "test only" drive through station that I've been using is easy and convenient and no more expensive than most other places (They accept any "emission test" coupons that are published in the local papers or arrive in the junk mail, but will only discount a maximum of $25 from their normal $50 fee.)

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Old 09-21-2007, 02:01 PM
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Join Date: Jun 2006
Posts: 9
Just failed Smog and question about %0

In a previous post, I noticed that the 0.0 numbers for the %O for the CA smog test numbers represent 100% Cat efficiency.

I just got these numbers:
Test %O Max Ave Meas Max Ave Meas
15 mph 0.0 81 21 56 for HC 685 150 590 for NO
25 mph 0.2 47 13 138 for HC 696 136 1000 for NO

Does the 0.2 under the %O mean that I should have run the car for at least 15 minutes at freeway speeds before the test so as to bring up the catalytic efficiency higher? Or are the numbers for 25mph just too high. I don't have the last smog numbers available for this vehicle.

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Old 09-21-2007, 03:45 PM
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Join Date: Jun 2006
Posts: 9
Thumbs up Successful Smog Pass

I just posted this morning regarding my 1994 E320, which failed at 8:45 AM.
Initial 8:45 AM numbers were:

15mph 1359 14.9 0 81 21 56 .47 .06 .11 685 150 590
25mph 1372 14.9 0 47 13 138 .44 .05 .27 696 136 1000

I read these threads regarding turning off the engine during testing and insuring that the car's cat is hot enough pretty extensively and checked that all out with my mechanic over the phone. He agreed with it all and suggested that I drive the car at highway speeds before retesting and trying again. Ran
car for 20 minutes at 65mph with A/C on high and did not shut engine off prior to test.

I just retested and here are the new results and the differences are astounding. Thanks forum dudes! for your help.

VLT Record # 13943: Time 11:13 AM 9/21/07


15mph 1359 14.9 0 81 21 12 .47 .06 .01 685 150 18
25mph 1372 14.9 0 47 13 5 .44 .05 .01 696 136 18

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