IF you fail, you need to look at:
1. EGR Valve
2. Fuel mixture ( too lean )
3. Catalytic converter.

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2007 C 230 Sport.

1989 did not have EGR on the M103 from my memory... that was the 1990 model year and after.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

one easy trick for passing a car with marginal nox[assuming you have corrected a lean fuel condition] is to pump up the rear tires to about 40psi.when a car sits on the dyno because of two rollers it has two bags on the tires and it takes power[extra push on accel]to make those bags move around the wheel.40psi should get you through.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

Thanks to Manny, Hit Man X, and David. After replacing air cleaner, running a can of 44x in 10 gallons of premium, replacing the spark plugs,
putting 40 lbs of air in the rear tires, and driving 125 miles on the expressway, it passed by 6 points--much better than last year's pass by one point.

The plugs were Champion...dunno who put those in! The deposits were built up, and the gaps wide.

The local Benz dealer had the right Bosch number H 9 DC non-resistor. I spent two hours looking on line to no success. Another hour calling local parts suppliers also brought no success...but when I called RBM of North Atlanta, they said, "Of course we have those!" The service manager drives a 90 300E and said, "That's the only plug to use." They cost $2.19 each.

Again, thanks!