Mercedes-Benz Forum banner

1 - 7 of 7 Posts

·
Registered
1987 260E
Joined
·
20 Posts
Discussion Starter #1
Our 1987 260E Fail California Smog Check. A friend of ours said that its probably a bad O2 sensor. It failed on NOx and HC's. We asked a friend of ours who's brother works for Mercedes in Germany. He said that we should only use BOSCH O2 sensor and it is very common for them to go bad on these cars. Is all this true?
 

·
Registered
1995 E320
Joined
·
2,510 Posts
we dont know anything about the condition of your car, how many miles, how old, what condition.

maybe it just needed a tuneup before you went for the smog test.

come back with pertinent details and we can start looking at the problem.
 

·
Registered
1987 260E
Joined
·
20 Posts
Discussion Starter #3
neanderthal said:
we dont know anything about the condition of your car, how many miles, how old, what condition.

maybe it just needed a tuneup before you went for the smog test.

come back with pertinent details and we can start looking at the problem.
The car has 221,584 miles. The car is in good condition. All maintenence is performed regularly. A tune up was performed about 2 days prior to the smog check.
 

·
Registered
E320 wagon
Joined
·
953 Posts
thsncc1701

If it was a very high reading it could also be catalytic converter if that year had the older type. A bad O2 sensor would show up as lower fuel economy .

I would spray clean the induction system - mass airflow sensor - air temp sensor - throttle body ,,,, just spray any brake clean - carb. cleaner ( about half a can ), down the hose /duct /thr. body .

This cleans all vacuum ports , sensor dust - air bleeds in the throttle body , many have been amazed by the results . I notice it in the low end torque and idle , just spray puffs to keep the engine from dieing . Give it a shot .
 

·
Registered
99-C43, 05-G55K, 71-280SL, 94-E320 CAB
Joined
·
2,282 Posts
Not sure how California performs the test, but if you just started your car and they used a sniffer in the tail pipe you would get an anomaly that would read high / failure.

If you have driven the car to operating temp and are waiting with the car at idle for the test to begin , your readings will be accurate pass or fail.

If it is tuned, then the O2 sensor or cat can be problematic.
 

·
Registered
85 300 TDT
Joined
·
2,260 Posts
Sounds like you need the $5 tune up that allowed my W201 to pass after two failures. Was tuned up and running perfect, just pushing out too many nitrous oxides. Go to the nearest Wal mart and buy a liter bottle of isopropyl alcohol - 70% or higher. Take it down to about half a tank and pour it in. Go on a 30-45 minute highway speed run before taking the test. My money says you come in under the limit. Try it and let us know.
 
1 - 7 of 7 Posts
Top