1989 300e failed ca smog!!! Yikes!
 

Took the 300e to the test only today and wow...I have never seen suck high ratings. Then again, I have never owned anything this old.


@15mph RPM:1637

HC:183 -FAIL (max is 110)
CO:1.46 - FAIL (max is 0.71)
NO:411 - PASS (772)


@25mph RPM:1437

HC:193 - FAIL (max is 85)
CO:1.52 - FAIL (max is 0.59)
NO:541 - PASS (max is 711)

Has anyone had any experience with this or even know where and how to start taking a stab at it? Thank in advance to all!

I think the idle could be waaaaaaay too high, at 15 mph, for your 6 cylinder.


Because for a V8 560 for instance, 650-700 rpm at idle, is on the money.


Avoid at all costs, an actual test where the result gets reported as a "Gross Polluting vehicle", that is a horror.


Generally speaking, Mercedes Benz gassers of that time burn very clean, if in good tune, at 139k mine, a 1991 California spec Mercedes Benz has never ever failed to pass a California smog test, not even once, in its whole life.

Either the O2 sensor is not working OR the mixture is so far out of adjustment that the O2 sensor can't work.

Have you done your maintenance? New plugs wires dist. cap and rotor. Fresh oil change and NEW FILTERS. Did you warm the car up for 20-30 minutes before you took it in?
You just can't take these cas from a cold start into the test with NO preventive Maintenance. Just cuz it passed last time doesn't mean jack this time ...as you found out.

BTW I think your EGR is working well because of the low NO readings. Change out the O2 sensor. When was your cat last changed ?

smog test
 

Hi,
My '87 300E with 204K just passed with no problems.
Anziani

'87 300E 204K (just sold)
'95 E420 115K
'93 300CE 160K (just bought)

On that motor everything depends on whether or not the O2 sensor is working and if the CIS system is adjusted properly....if its not....you'll be wasting gas and polluting...

Yea, I was leaning toward the O2 censor... Anyone know the way to check voltage or tell if the censor is working? I really think its running rich, by a bunch.

As far as a high idle goes, in P/N/D idle is within spec. The car was run for way more than 30 minutes before hand. Everything is done but the cap + rotor, but I really think its too rich. Also, there is no EGR on this car.

Thanks everyone, keep 'em coming!

I would take it by my favorite Indy and have him set the CO, mixture and idle. A generic 02 Sensor is only about $40.00 USD here in So Cal. If you need a good Muffler guy I have one in Lancaster, CA. He uses Bosh Generic O2 sensors and they work and are inexpensive.