Lambda Control 1 & 2???

BMR740IL · Post by **BMR740IL** » Mon Jun 18, 2007 11:00 pm

I have a 1995 740IL.

Can anyone give me an idea what the Lambda Control #1 & 2 problem consists of and what do I have to do and what parts are needed to replace and fix problem?

My engine starts off COLD (rough start) but after it warms up, it runs smoothly. I changed the Idle Control unit already (NEW) and I use Super Unleaded Gas, but it still has the same problem.

Anyone?

Thanks
Vee

colin · Post by **colin** » Tue Jun 19, 2007 5:23 am

Oxygen sensors. Click this link and look at part #9. Somebody please chime in if I'm wrong, but I'm pretty sure your 1995 car only has these two. You should be able to find this part from anyone selling BMW parts.

edit:

DIY link 1
DIY link 2

Since your car is pre-1996, you only have the "pre-cat" sensors, so ignore the mentions in the above links for "post-cat" sensors. Have fun.

victory1auto · Post by **victory1auto** » Tue Jun 19, 2007 9:01 am

"Lambda Control" codes on BMWs are usually not related to the oxygen sensors. The symptoms you cite are consistent with air-leak problems. When the motor warms up a bit and goes "closed-loop", the O2 sensors correct for the problem and the motor runs OK. Lambda codes are set when the O2 correction exceeds preset limits, as they would when the system is correcting for an air leak.

Vic

ThumpersGP · Post by **ThumpersGP** » Tue Jun 19, 2007 11:33 am

To bolster what Vic said, on the 95 M60 engine,air leaks can be from several areas.

-intake gaskets( been improved over the years)
-intake air pressure regulator(back of intak manifold)
-general gasket leaks(look for oil leaks)
-dipstick secured?oil cap?

just some things to look for

Ray

jlnmd · Post by **jlnmd** » Wed Jun 20, 2007 4:30 pm

O2 sensors input is ignored by the DME until the engine warms up. SO if your engine is rough when cold but smooth when hot, chances are the problem is NOT with the O2 sensors.