e38 (95) rough idle sluggish acceleration ✔ engine light codes 012, 203, and 201

[Eloiajohnson]

I have a 95 740il rough idle, has sluggish acceleration and exhaust smells Rich, I codes 012, 203, 201 all say o2 sensor 1 and 2, o2 sensor control 1 and 2. Things I have replaced : both o2 sensors (2mo ago) fuel pump and filter (2mo ago) valve cover gaskets and oil pan gasket last winter. I deleted the cats last summer.



Things I did today voltage tested the injectors in bank 1 (upon further reading of codes) all gave 12v on power and .71v on ground. I also tested the ohms all read 15.0...



I also checked the coils and plugs. Plugs were all light in color except 1 (#2) which I read means it's lean. I also did an ohms test on the coils all were in good reading per specs...



Pls help!! He's running like shit! I have an oil leak which seems to be coming from rear main (which I have ) and was gearing up to get him on the lift to replace when this happened! HELP!

[CD05001CIA]

I have a 95 740il rough idle, has sluggish acceleration and exhaust smells Rich, I codes 012, 203, 201 all say o2 sensor 1 and 2, o2 sensor control 1 and 2. Things I have replaced : both o2 sensors (2mo ago) fuel pump and filter (2mo ago) valve cover gaskets and oil pan gasket last winter. I deleted the cats last summer.



Things I did today voltage tested the injectors in bank 1 (upon further reading of codes) all gave 12v on power and .71v on ground. I also tested the ohms all read 15.0...



I also checked the coils and plugs. Plugs were all light in color except 1 (#2) which I read means it's lean. I also did an ohms test on the coils all were in good reading per specs...



Pls help!! He's running like shit! I have an oil leak which seems to be coming from rear main (which I have ) and was gearing up to get him on the lift to replace when this happened! HELP!

How do you know that the right side o2 sensor is connected to the right side DME input and the left side O2 is connected to the left side DME input?

Does the engine run fine for the first two minutes when cold? (initial cold start after sitting)

What is the condition of the 'rubber' parts on the back of the intake manifold. (related to vacuum brake assist and PCV (positive crankcase ventilation)

Is your PCV valve stuck shut or disintegrated?

Double check that all coil packs and fuel injectors have there electrical connectors properly seated.

Is your idle control valve functioning?

[Eloiajohnson]

How do you know that the right side o2 sensor is connected to the right side DME input and the left side O2 is connected to the left side DME input?

Does the engine run fine for the first two minutes when cold? (initial cold start after sitting)

What is the condition of the 'rubber' parts on the back of the intake manifold. (related to vacuum brake assist and PCV (positive crankcase ventilation)

Is your PCV valve stuck shut or disintegrated?

Double check that all coil packs and fuel injectors have there electrical connectors properly seated.

Is your idle control valve functioning?

Gm I'm up early today and will check thoes things and report back today. As far as the O2 sensors when I bought the sensors there was no difference in the 2 (same sensor both sides Bosch) and like coils or leads I replaced each, one at a time .... If thats what you were asking...yesterday's cold start was rough it smoothed out "a little but still ran awful" but ima do what you suggested and come in here and let you know

[TheAngryBear]

codes 012, 203, 201 all say o2 sensor 1 and 2, o2 sensor control 1 and 2

What are the actual codes and definitions? I don’t recognize those and the definition is going to be key to determining what is going on.
With control limits, I immediately go to vacuum leaks, exhaust leaks, MAF validation, etc.


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[CD05001CIA]

Gm I'm up early today and will check thoes things and report back today. As far as the O2 sensors when I bought the sensors there was no difference in the 2 (same sensor both sides Bosch) and like coils or leads I replaced each, one at a time .... If thats what you were asking...yesterday's cold start was rough it smoothed out "a little but still ran awful" but ima do what you suggested and come in here and let you know

Ok so it is not likely the O2 sensors because the car runs on a look-up table until warmed up. You stated "rough cold start"

Waiting for further responses to other questions . . .


follow on to questions: after you have checked the above items, then-> dis-connect the MAF then start car - report back.


LOTS ! of info to study and research here --> http://www.meeknet.co.uk/e38/

[Eloiajohnson]

Here's the update: it was my PCV/CCV and booooyyy was it hell getting off!!!

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[Eloiajohnson]

Last update and boy do I feel stupid!! ����*♀️:
I did all that work only to find out my intake boot had a huge hole in it.... Smh... go figure...smh