I have a 1984 380se with high NOX readings and cannot pass MA emissions. I tried to reduce by replacing EGR filter AND adding Techron. No go. I also added DryGas before the inspection...readings were higher than first test!

My mechanic said that the only sure cure is a new cat...OEM is $500...Arvin is $70. Is Arvin any good for a few years?

Thanks for input

The car has about 100K miles and is certified to CA emission standards. The NOX test was about 4.0 with an acceptable limit of 3. I am told that Arvins do not convert to a CA standard car.

Would this help you at all ?
http://www.ecatalyticconverter.com/mercedes-380_series-converter.html

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2007 C 230 Sport.

You need to do a complete functional check of the EGR system including the valve and the control system.

Duke

thanks, manny and duke. those converters look like decent prices. there is only an egr filter on this car and that was replaced......

The MA limit for NOx is 3.00. My 1984 380SE had a reading of 3.46 and failed. I have tried Techron and I also replaced the EGR. The next test came up at 4.47....a whole point higher!!! So, I had the catalytic converter replaced...latest test is:...........4.71!!!! Even a bigger failure.

Any suggestions on how to bring down the NOx on this CA emissions car? Thanks!

How is your car preforming in general... start up... gas mileage...
do you own a multi meter or any other testing equipment for fuel or vacuum pressere?

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-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/showpost.php?p=831799&postcount=13
http://www.peachparts.com/shopforum/showpost.php?p=831807&postcount=14

car is running well. The O2 sensor was changed about 15k miles ago.

I checked another post...and I might try to retard the timing about 6 degrees...it looks like that might be the solution.....

Does it burn oil? That could foul the O2 sensor. Also, look for vacuum leaks.

MP

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Thanks....it runs well...and no oil burn between changes....

As I said before you need to do a COMPLETE FUNCTIONAL TEST of the EGR SYSTEM, which would include both the valve and the system that controls the valve; "replacing the EGR" does not transmit meaningful information. What functional tests on the EGR valve and control system were accomplished? What did they indicate, and exactly what parts were replaced?

If the EGR system is functioning properly, you can make timing map modifications, though I'm not sure how this is done on your particular engine, but I know how to do it on an M103 even though the initial timing cannot be changed.

Read the following thread and the thread it refererences. Though my objective was to reduce HC - and I did by 30 percent - I also reduced NOx by about 90 percent.

http://www.peachparts.com/shopforum/showthread.php?p=833484#post833484

Duke

I replaced plugs and retarded timing 10 degrees......it passed with a 2.87!

Thanks!