190e smog problem: need tech help

I need help my recently rebuilt 190e 2.6 failed Calif smog miserably. The hydocarbons were 3x max and the Nox was pretty high, both dropped in the speed portion but were still too high. I need direction; i am pretty fair
amateur. I am thinking the cat are due to be replaced (there appear to be 2 of them and the back doesn't appear to be replaced in years. Or thinking about this all wronf and should looking at a sensor such as the air mass sensor. I don't mind repairing but i don't want to be throwing money for no reason either Any help would be appreciated. Thanks, Jim
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I'd replace the cats as the last thing. I suggest you first check the engine's tune-up specs, especially the ignition timing - it may be a bit retarded. Also, the air / fuel ratio can be adjusted - by a shop with an emissions tester. New spark plugs and wires may also help, depending on the age and quality of the existing.
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New plugs/wires/cap/rotor timing is non adjustable, several sensors control the timing car runs reasonably well with maybe with a slight roughness at idle Eventually it will go to shop but shops around here are sketchy 1 minute professional next minute there off into space I am trying to get enough knowledge about the problem before i end up there thanks for the input bo

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Given this description of the engine's condition and its slightly rough idle I'd check for a small vacuum leak. That could be a split hose or a leaking intake manifold gasket. I say that because too lean an air / fuel ratio at idle will cause, as you say, roughness which is poor combustion resulting in excess HC at idle. As the engine speed increases such a vacuum leak, being constant, becomes less and less of a factor which could explain the emissions test result.
Another idea: dirty fuel injectors, add a can of TECHRON or equivalent.
Again, replacing the cats would be my last resort for if the cats were bad the emissions at speed and during acceleration would be excessive IMHO but they're not.
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In my decidedly non-professional opinion, I'd say that if it's that far off new cats are not the problem. Sensors sound like a good place to start. You might take it to your local independent shop for a diagnosis, should cost you 1 hour of labor. Then you can change the sensor(s) yourself.
MC

2
no
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