190E 2.6 Failed CA SMOG - PeachParts Mercedes-Benz Forum

dwayneseah · #1 11-29-2007, 03:49 AM

Second time testing, first time results were a bit higher. Now they are better but still failing. The car was hot during the testing, so i don't think that was the issue. I have used the X3 pin to tune the air/fuel to as close as .5 according to my multimeter. Before my 2nd test, I changed the plugs, cleaned the idle control valve, checked OVP, Air filter is clean, put 91 premium, and so on. Any other suggestions. I have not used injector cleaner or sea foam on the engine yet. Do you guys think that seafoam will help me pass?

ASM EMISSION TEST RESULTS for 190E 11/26/07

15mph
rpm 1853
% CO2 meas. 14.4
% O2 meas. 0.9

HC (PPM)
max 114
ave 31
meas 147

CO (%)
max 0.73
ave 0.10
meas 0.34

NO (PPM)
max 785
ave 237
meas 1240

Results FAIL

25mph
rpm 1430
% CO2 meas. 14.5
% O2 meas. 0.7

HC (PPM)
max 88
ave 20
meas 74

CO (%)
max 0.61
ave 0.09
meas 0.11

NO (PPM)
max 724
ave 199
meas 847

Results FAIL

dwayneseah · #2 11-29-2007, 03:54 AM

Also, on my test results, I failed one of the visual inspections.
It says that I failed the MIL/Check Engine Light. None of the error lights on the dash are on so I don't know why I failed this inspection. Wat is MIL? Does anyone know what this inspection is? Thanks.

mbdoc · #3 11-29-2007, 08:32 AM

The MIL means malfunction indicator lamp, in other words the check engine light.
It must come on with the key & go out when the engine is started.

WHAT year car? If the car is a 1990 or later then possibly you have a EGR system that isn't lowering NOx.

dwayneseah · #4 11-29-2007, 12:42 PM

It is a 1990. Oh Ok, maybe someone disconnected the check engine light so that it does not come on at all. I will check that out.

What can I do to remedy the EGR system? Can it be serviced or must I replace the parts? And if so, what would I need to replace?

shingleback · #5 11-29-2007, 01:10 PM

A lot of failures tend to be due to a bad oxygen sensor; have you checked yours?

splinter · #6 11-29-2007, 02:10 PM

Duke2.6 has some good info here-
http=://www.peachparts.com/shopforum/showthread.php?p=833484#post833484

mbdoc · #7 11-29-2007, 02:29 PM

Making sure that with the engine running & applying vacuum to the EGR valve that the engine starts shaking & running rough.

manny · #8 11-29-2007, 06:23 PM

Quote:

Originally Posted by shingleback

A lot of failures tend to be due to a bad oxygen sensor; have you checked yours?

With his low CO and HC readings, I doubt the 02 sensor is an issue here.

dwayneseah · #9 11-29-2007, 08:46 PM

So basically NO and HC problems have to do with the EGR? I want to have an idea of what needs to be fixed.

manny · #10 11-29-2007, 09:02 PM

The EGR system is responsible for NOx reduction.
High HC is usually caused by such things as ignition problems ( misfires ), mechanical problems ( oil consumption ), etc.
Since you're okay on HC, I would focus totally on the EGR system.

Hawk180 · #11 11-29-2007, 10:15 PM

I was under the impression that the EGR was usually only activated during warmup. When the engine is running and warm, I have been told that the EGR remains closed. I suppose that this is erroneous.

dwayneseah · #12 11-30-2007, 01:09 AM

I do fail HC though on the 15 mph by about 30. Any ideas on that? I will check out the EGR system but I can't afford to keep restesting the car. I want to get it right the next time. Thanks guys.

david s poole · #13 11-30-2007, 09:57 AM

based on the numbers you provide your car is running lean.you have too much o2 remaining after combustion.should be between 0.0 and 0.3%.your high hc.probably caused by small missfires that you cannot feel.by richening mixture you will see hc fall and o2 fall and the dreaded nox should drop to 450 ppm or less.

manny · #14 11-30-2007, 11:55 AM

Quote:

Originally Posted by Hawk180

I was under the impression that the EGR was usually only activated during warmup. When the engine is running and warm, I have been told that the EGR remains closed. I suppose that this is erroneous.

All wrong.
The airpump is activated on a cold engine, to " light up " the catalytic converter.
EGR is introduced on a warm engine when you're cruising.

dwayneseah · #15 11-30-2007, 04:35 PM

I just did a retest and it happened to be raining. The guy did a rain test to dry the tires. My results were a little better. Not significantly. Maybe 3-5% better. However, now the O2 reads 0.3%. The CO at 15 mph is reading 0.2 now instead of 0.34. At 25 mph the CO reads 0.05, which is now lower than the avg of 0.09. BUT! the HC and NOx results are almost identical to the previous test. The HC and NOx improved by about 3-5% but still fail.

Question for David poole: since my O2 percentage is down to 0.3%, could the car still be running lean? My O2 now reads 0.3% but my HC and O2 stayed virtually the same. Only the CO went down significantly. I think this is due to the "rain test" in which the tester runs the car on the rollers for about a minute before testing. Can I conclude that my mixture is almost on the spot?

Question for all: This is my 2nd test with this place. The guy told him after I failed today that it is my catalytic converter that needs to be replaced. It is not OEM, and the previous owner had replaced it with an aftermarket one. I am not sure if he is right or not, but what are the chances? Today my CO and O2 readings went down alot when the cat was allowed to warm up. Should I assume that my cat is good? Could the cat be bad at reducing NOx and HC? Should I replace it?

And if I do replace the cat, I don't want to pay for OEM, too much $$. Any suggestions for good aftermarket cats that are cheap? Money is tight right now.