parnelltk

1992 400E 196K Miles - CA Smog Check FAILED at IDLE

I figured out again how to pull the diagnostic LED blink codes.
I got 3 codes:
2
21
26
After clearing each code, I then wound up having to disconnect the battery for several minutes to get the Check Engine Light OFF. Is there another way?

I also attempted my CA Smog Check yesterday. I really warmed the car up thoroughly with about 20 miles of high-speed and some low-speed driving.

It failed on Hydrocarbons (HC) at Idle:
Measured HC 197ppm vs. Max Allowed HC 120ppm (and avg. 29ppm)

So I am very high on Idle HC and looking for most effective things to check and repair to pass right away.

Overall the car runs well and idles smoothly.

Spark plugs, Wires, Rotors, Caps are about 30K miles old. I do not see that as old enough to replace (visually wires etc are in good shape). Other opinions on replacement interval for these items?

What else?
Catalytic converter is fairly old. Is the Catalytic Converter a big factor on HC?
Catalytic Converter is also very expensive - I am told $1000??

One mechanic has told me that for about $150, he will "clean something" and it will pass. He says "you do not need to know what I clean!!"

Is there any possibility this mystery cleaning could work??
Urban myth?

I would really appreciate some insight and advice from the Experts here!

Thank you.
Pardon my repost but I really need some insight here.

Kim

Wigman

That is one shady mechanic!

A full assembly for cat n rest of exhaust system does run up to 1000 bucks, but just cat it'll just cost you anywhere from 150 to 500 depending on brand and where you get it.

can't really help you much with smog issues since my state doesn't really do smog test.

p.s. if that "cleaning" thing is what i'm thinking about, its something that you can do on your own. What im thinking is using a brand fuel cleaning system and "I.V. drip" directly to Throttlebody/between T.B. n MAF by drilling a hole in the plastic. I have not done this method on a benz yet.

Jim's500E

You might have alot of carbon build-up in the cylinders...your mechanic will prolly use a 'top-end' cleaner that's sucked into thru a vacuum line. It works well btw....the car will run so much better and cleaner, better mpgs too.

He prolly use a throttle body cleaner and a gas treatment too. 'Wurth' makes a trio-kit that I have used a few times, totally worth it. Nevermind what MB says about engine additives/cleaners....these are safe (Wurth products).

MacVidMB-V8

My '93 400e has 123K and has always passed with flying colors.

Did you get this resolved?

Airfilter check, go do some serious kickdowns to get high RPM and "blow out the carbon".

Could also try cleaning MAF with carb cleaner.

parnelltk

Well, I did pass by doing some work with a particular shop.
I am not exactly sure what they did, and he said it would only pass for a limited time!! Very mysterious, right??
It did involve some type of carbon cleaning I believe.
The shop did not want to give much information.