300E Emissions Test Results
 

Hi,

Can anyone tell me what can be said of the following results:

HC 0.542 Standard is .455
CO 2.704 Standard is 3.419
CO2 330.0 No Standard listed

State of IL

Car: 1990 300E 134K miles.

Just thought something might be told from the results. Seems to me that the car is running rich.

Thanks.

chicago124

There is nothing major wrong with your car. Was your cat good and hot? This is the most important thing. Unless the cat has been replaced, I would say it is down to 10-15% efficiency.
Run some injector cleaner though it, run at high speed for 20-30 miles. Gas up with new before retest.
Check plugs, gap, condition. Check wires, resistance. RorR air filter. check for vacuum leaks before & after the intake. If possible scope the O2 for sluggish response.Check timing.Check coil that its hot enough. Lastly, check EGR ( if equipt) for flow constrictions. ie carbon build up.

Good Luck.

Hi,

I passed the test in spite of a fault code for the Oxygen Sensor. Go figure.

The Cat was pretty hot in that I drove for about 20 minutes before the test.

Perhaps a failing 02 sensor might have caused the high HC level?

I've changed the plugs about 3000 miles ago and the old ones were perfect -- light brown in color.

Wires were done about two years ago.

I plan on changing the oil this weekend and running a couple of bottles of Techron before the change. The injectors are fairly new but cleaning them can't hurt.

Thanks.

chicago124

If your O2 sensor has failed, you will be running open-loop. Likely your pre-cat HC emissions are very high, and the cat is sucking it all up, consuming its 9 lives rapidly. Save the cat and fix the problem - O2 sensors are much cheaper.

Steve

Hi Steve,

Thanks for your reply.

I agree with you -- I forgot to mention that I'll be replacing the sensor this weekend too.

I'd rather not have to replace the cat:-)

Regards,

chicago124