I have 94 740i and have had the check engine light coming on the last several days. It has been intermittent. First, the car sat for about 9 days. When it was cranked, it ran rough and shut down. The battery was low so i replaced it. After that, the car has been running rough until it warmed up and then performed fine. Again, the last several days the check engine light has come on and off. Today it is on constantly and the car runs but rough. I did the "stomp check" and got the code 1222. HELP!!!!

http://www.bmw4life.com/stompTest.htm

"1222: O2 lean/rich control stop"

That seems like the culprit, considering your performance. Replace the O2 sensor.

Thanks for your response. Since I posted, I went out, disconnected the battery again, and tried the stomp test again after I had run the car. Nothing happened. I will try the procedure you listed. Thanks, will let you know how it goes.

Chance are, the light will soon come back on. All you did was reset the system. Assuming it didn't mistakenly give you the light before, it will come back. The O2 sensors have to be replaced every 75k (or less?) miles or so anyway.

Sounds like an o2 sensor to me.

let us know if that fixes it. it helps us all to get an answer :)

The O2 sensors have to be replaced every 75k (or less?) miles or so anyway.

I think the recommended interval is 100K miles, and it's an EASY job...

I think the recommended interval is 100K miles, and it's an EASY job...

Thanks for the clarification :)

Thanks to you all. I noticed that the Rubber Boot that connects between the T-SHAPE IDLE REGULATING VALVE and the HOT-FILM AIR MASS METER (on the front of the engine above the radiator fan). I went to the Dealer and it was $136.13 but they sold it to me for $90.00. I replaced and disconnected the battery. WOW! The car runs like new and the check engine light is gone. A rubber boot allowing to much air.

Common vacuum leak issues. Good find though. If this happens again, take some carb cleaner and spray around the vacuum lines and if the engine revs, you've found the vacuum leaks :)

And yes, per All Data, O2 should be replaced every 100K miles.

I also have the same problem with my 94 740i. Check engine light comes on and rough idle in the morning, then after about 10 minutes of drive time its fine for the rest of the day. Curiously, the car was fine all summer (The average temp here in Palm Desert during the summer is 110-115, cooling down to about 99 by midnight). But as it got cooler when fall came, the problem started happening again. I've replaced the MAF and the "silvery" idle control valve. I also replaced the throttle body boot and checked for gasket leaks as recommended and replaced the air filter. All the plugs are new and I have individually grounded each coil. Still no help.

There is an intake air temperature sensor (The #2 O2 sensor, I believe) located on the forward passenger side of the intake manifold. Could this be the source of the problem and/or is there any way to test it? (Hairdryer and an Ohmmeter?) Schematics reveal that it is second in line electronically to the MAF. This is the least expensive of the 4 O2 sensors but still I'd rather not have to spend another $50 if the problem lies somewhere else.

Thanks for your help.

Hello I am having similar issues. I have a 2001 740I in the morning and on days when car sit for hours, the car idle very rough until it warms up. My engine light stays on no blinking. Car feels like its running on seven cylinder. Car has 114k on it. Can anyone help me with some advice

Many times this symptom is associated with the MAF (Mass Air Flow), once called an automatic choke. If you had said the CEL light was on and the car seemed to be running fine (no loss of power, no rough idle), I would suggest a Cam Position Sensor.

The giveaway seems to be the rough idle when cold, smoothing out once the car warms up. In the last year, on two cars (one a Nissan Sentra, the other a '91 BMW 325i) the symptoms exhibited themselves (though neither car triggered a CEL light), and then, separately, my '01 740i CEL light came on but the car ran fine. The two cars turned out to both be bad MAFs, while the 740 turned out to be a cam position sensor.

So...check for leaks in the black rubber tube leading to and just aft of the MAF for cuts or breaks. If you cannot find any breaks, find a LAND ROVER dealer, and buy the MAF from them. The ROVER uses the same MAF as BMW (same part numbers, even) for a lot less money. Replace only the electronic module, the part which plugs into the large black plastic tube, and it should run like a champ again. Some folks even use VW MAFs but the shape is a bit different on the VW model.

Do a search on this forum (Key word: MAF, Rover MAF) and you should find some writeups. Good luck.

jake

Unplug your MAF when the engine is cold, and start the car. If the car starts up and runs then you have narrowed it down to the MAF. Google "Rover MAF BMW" and read the posts, one even gives the part number for the Rover MAF.

jake

Thanks Jake I will try that. I will let you know how it turn out