Code 1222 - ? Replaced O2 sensor

[scott 4991]

Hello All.. I have a rough running 1990 535i. The code is 1222, and I have replaced the 02 sensor, which seemed to fix the problem for about 10 miles, then it's running the same - rough. The 02 sensor was dark black when I pulled it out, telling me I'm running very rich. I have also replaced the Idle Control Valve.

Read in the Bently book perhaps a water temp sensor?

Ideas?

Thanks

Scott

[scott 4991]

Looking for things to look for.. I know there are good mechanics out there..

sc

[timandbim]

i thought the code for the oxy sensor was 1221... i remember thinking 'so what do you replace for a 1222, then?' after i replaced mine... i think i had decided it was not the sensor itself but somewhere in the area around it (wires or fuse or?)- did you reset? - are you code free now? sorry this doesn't help much... somebody else knows more than me, i think...

[Ferret]

Check for vaccuum leaks and that your maf is good.

Unplug the maf while the engine is running and see if it makes a difference.

[shogun]

The code error oxy sensor is in most cases not the oxy sensor but something else which causes the oxy sensor to send such messages and to react and give wrong signals to the DME.
As Ferret already said, checl the intakes for vacuum leanks, and that your MAF is good. Often it is the MAF.
Distributor and rotor checked?
If you have a Bentley Manual, I believe the test data are mentioned there for your model.

Read in the Bently book perhaps a water temp sensor?

Yes, also a possibility, if there temp sensor is faulty and the DME always belives that coolant is cold, the mixture will be richer.
As you have a Bentley, just get your multimeter/DMM and test the temp sensor. Note, that there are 2 , one is for the DME, one just for the indicator in the dash which does not matter what it shows in this case.

[scott 4991]

Thanks for the suggestions. I will recheck all the above.

sc

[ahlem]

I was reading your old post. I have a similar code showing up. My car starts and runs fine but seems to have a rev limiter on onramps and the check engine light blips on from time to time on trhe freeway. I changed my O2 sensor that had 50k miles on it. The old one was hard to remove but looked reasonable. The next thing is to check the cap and rotor.
I have 285k miles 1990 535 5 speed Conforti Chip K&N air intake Racing Dynamics Exhaust.

[scott 4991]

I disconnected the battery, reset the comptuer.. all worked fine. May want to try this if you have not.

sc

[ahlem]

In the tech section it says how to clear the codes. I tried it. It didn't work. My 1222 code just keeps repeating. When you disconnected the battery did it clear the code? How long did you have it unhooked? I need to check to see if I've got the radio code or if there is one before I try this. In my case, I can feather the throttle slightly when on the freeway and the check engine light turns off. Should I expect the drag race onramp test to be better after I clear the code?

[Tiger]

Most likely your air mass sensor is bad. Usually when car spits out O2 error, it is Air Mass Sensor because the computer is telling you that the O2 reading is way out of ball park. A pro would look at 02 reading while car is running to see if it register anything... if it is zero then O2 is dead... and they will also check if the 02 sensor have 12V for heater...

Once they verified that the 02 sensor is working, it is most likely to be the Air Mass Sensor that is bad.