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  #1  
Old 09-24-2003, 11:17 PM
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Location: Vancouver, Canada
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failed emission readings

I had my non-MB mechanic run my 85' 190E car in his Snap-On Emission Analyzer and he said that I'm off the charts on the following readings:

HC - Hydrocarbons and
CO - Carbon Monoxide

His solution ......... new Catalytic converter and O2 sensor. Dope!

Has anyone had this problem and use the same approach in fixing the problem? Also, are there two types of O2 sensors with my model year? One at the exhaust manifold and one at the catalyst (got those info from FastLane).

thanks in advance!
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  #2  
Old 09-24-2003, 11:44 PM
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Try

Well my buddy, has a 1987 BMW which failed the extensive New Jersey emissions, before going through costly repairs, he put in this fuel system cleaner from Pepboys by the name : Guaranteed to Pass Inspection!! and sure enough he passed the second time round. I am not sure what it does to the system but he passed, His CO was down and were the Hydro Carbon readings.
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  #3  
Old 09-24-2003, 11:47 PM
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How do you figure you need 2 oxygen sensors? I'm pretty sure your car only takes one. I don't see 2 separate oxygen sensors in FastLane. Looks like a MT one and AT one if anything.

Sixto
95 S420
91 300SE
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  #4  
Old 09-25-2003, 12:19 AM
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I heard about that those fuel additives ........ but the shape that my car is in I know that I might need more than just those additives. I will definitely add it on though when the time comes for a re-test.

when I "show all products" in the Oxygen part menu it does show three pictures but two of them are the same.
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  #5  
Old 09-25-2003, 03:20 AM
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smoke gets in your eyes
 
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You're right about the third oxygen sensor. But I'll bet my neighbor's cat your car only takes one. A call to Phil should clear it up.

Any mechanic should be able to test an oxygen sensor. If yours is original, age alone says it's ready for retirement. BUT, it might not fix your emissions problem. Especially the CO part.

If you have no problem accelerating with a full load and getting to 160km/h fairly quickly and you don't smell sulfur/rotten eggs, I doubt your catalytic converter is bad.

You and your mechanic should go through this article and see if anything applies. http://www.peachparts.com/Wikka/EngineControls
Ignore the blocked EGR passage part.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD
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  #6  
Old 09-25-2003, 04:33 AM
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thanks for the article link .......................

When you described the symptoms of a possible bad catalytic converter I've come to realize that I have some of those problems.

My car does have a problem accelerating with or without a full load. I find I have to really floor the gas pedal to get the car going but the pedal response get's better when I get to a certain speed. Any ideas?
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  #7  
Old 09-25-2003, 08:03 AM
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My '86 190E 2.3 failed HC a few years ago. Came in around 244ppm, limit was 220. Did bunch of stuff including cap, rotor, wires, O2 sensor, oil change, plugs, air filter. After a couple of tries, replacing some parts each time. Finally passed with a HC of 167ppm. Year later had to go thru again (since I was soooo bad last time), passed with a 66ppm. I had done NOTHING different. No tune-up or other parts. Just oil change. Did have a slight exhaust leak after the cat but forward of muffler. Maybe it was pulling in fresh air at the leak. My own opinion is that your results are more related to the phase of the moon, the T-bill rate, which rerun is on tv tonight, etc. Truth be told, cat is probably about shot. If I have to replace the cat, I'll probably get a whole exhaust system from Time-Valve and put it on myself.
Funny thing on your readings was the CO. That says too much fuel/not enough air. Dirty air filter and bad O2 sensor probably first things to check. If the O2 sensor is old, just replace it. They age and go bad. Sensor is not too hard to replace. Connector is under carpet on passenger side of floor pan near front edge of seat as I recall. If the sensor was bad, you may want to take the car out for an extended run in maybe Montana or somewhere you can do an "Italian tune-up" to see if you can burn off some of the crud in the cat. BTW, do the car burn much oil? that can put the numbers thru the roof.
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Old 09-25-2003, 08:07 AM
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To pass the CO test, add 10% methyl hydrate to the fuel: solves any CO-problem.
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  #9  
Old 09-25-2003, 09:13 AM
inspector1
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Re: Try

Quote:
Originally posted by Theurig
Well my buddy, has a 1987 BMW which failed the extensive New Jersey emissions, before going through costly repairs, he put in this fuel system cleaner from Pepboys by the name : Guaranteed to Pass Inspection!! and sure enough he passed the second time round. I am not sure what it does to the system but he passed, His CO was down and were the Hydro Carbon readings.
To Begin:
These additives are a rip off. We took 20 cars that failed emissions by different degrees, slightly( .2 to .6 gpm) moderately ( .7 to 1 gpm) and a 'gross polluter' ( 1.2. to 3 gpm) added what is probably the same additive, retested them and the maximum improvement was only .2 gpm HC, .4 gpm CO- ( gpm=grams per mile of pollutant)

BobK:

A well tuned vehicle of any make can have as much as 20% variation in emissions from test to test, when tested, the emissions levels are analyzed by the infrared and non-directional IR spectrometer at around 12000 readings per minute, from this data the sample mass or percent is calculated from a cummulative reading every 2 seconds, with a running average compared to a standard thatr may be a maximum cut point, a phase cut point based on distance traveled, or a statistical cut point based on emissions data from h8undreds of tests done on the same make ond model of vehicle.
The analyzer itself has a variation of 2.5 to 5%. depending on type. And in the case of refremista, if your shop had not calibrated his analyzer as per SOP's then it is hard to say how accurate his readings were.

The first thing to do as a fix is determine if the engine is in fuel control, if so and the HC CO reading s are still too high to pass but cannot be improved, then this might indicate a worn out catalytic converter. A good test is called an intrusive test where the O2 levels are sampled before and after the cat, if the are close, say 13.5 to 14 before and 15 of so after then the cat is not working, another way is to take CO2 readings at tailpipe without the O2 connected, if around 15% when tested in concentration or 100x more than HC if read in mass, then the cats OK.

VRONSKY:
adding ME(H2O) is not a fix, high CO indicates deviation from from stochiometeric fuel control thus a problem exists in emissions control components that may lead to drivability problems in the future.


Most of the fixes suggested here are a good place to begin with repairs that will enable your vehicle to pass the emissions test.
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  #10  
Old 09-25-2003, 09:54 AM
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Re: Re: Try

Quote:
Originally posted by inspector1
VRONSKY:
adding ME(H2O) is not a fix, high CO indicates deviation from from stochiometeric fuel control thus a problem exists in emissions control components that may lead to drivability problems in the future.


Most of the fixes suggested here are a good place to begin with repairs that will enable your vehicle to pass the emissions test.
Correct, it's a trick to pass the test, not a cure for the problem.
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  #11  
Old 09-25-2003, 01:44 PM
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Hey inspector! Good info. Nice to have a knowledgeable source on the chemistry and workings of the inspection system helping. My theory is pretty simple: Whatever I drive, be it city car or huge SUV, I want it to be as efficient as possible (probably the German in me). I tend to set up my cars for good fuel mileage. Usually just one notch rich if adjustable. That way the NOX is kept down and I let the cat eat the HC. I had a '77 Suburban (tow beast) with small block 400, Quadrajunk carburetor, headers and dual exhaust with NO cats. (Legal for '77 HD emissions). Came in with a 122 HC and all others in spec also. Fellow at the testing station could not believe it. Simple really. Low miles engine (60k). Good state of tune. I was able to tease a couple of MPG out of the truck by keeping it in top shape and on that truck, that's a big percentage!
Nowadays with closed-loop systems, it's just too easy. Now if we could just get the automakers to distribute all the OBDII codes. Then we could all get our cars running right with out paying thru the nose.
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  #12  
Old 09-28-2003, 09:50 PM
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finally passed emissions!

I managed to pass the emissions test finally .......... the initial analysis turned out to be bogus from my non-MB mechanic. I managed to get hooked up with a couple of dudes that run an MB shop. They obviously figured out that my EHA had been disconnected ............... so they re-hooked it up, ran it through some tests and voila passed with flying colors. They also changed my plugs since leaking oil got to them.

That seem to get rid of my high idle problems as well.
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