engine running rich

My 95 540i is running rich there is fuel smell coming from the exhaust. The check engine light comes on and goes off its intermittent. I am wondering if an O2 sensor would cause this? I am new to bmw is there a way to check the computer codes?

Sounds like you are on the right track. You can do a procedure called the stomp test. Either search here or google it as it is a little long winded to explain it here. Basically it is a way to trigger the on board diagnostic computer to display any error codes using a series of flashes of the CEL light on the dash.

Let us know what you find.

Steve

I did the stomp test and it cane up with code 1213 O2 sensor lean/rich c/s anyone know what this means? the cars exhaust smells like fuel. Should I replace the secondary O2 sensor? where is located? 95 540i

Thanks

Have you downloaded the bentley manual? It has all the troubleshooting, diagnosis and fixup steps that you need to follow in this situation. Search these forums for the download link. Good luck and let us know how it goes.

I have the bentley manual it really doesn't say much about rich fuel mixture. I looked for vacum leaks but I couldn't find any. the engine has 193,000 I dought any O2 sensors have been replaced. would a faulty O2 sensor cause a rich mixture or could it be a bad mass air flow sensor?

BMW recommends replacing the O2 sensors about every 50-100K miles (I can't remember which). Anyway, you should replace both O2 sensors, especially since you have an error code for it and you have so many miles. Bad O2 sensors will definitely screw with how your engine runs. The E34 only has a pre-cat, two in your case since it is a V8. It's an easy DIY on the 6 cylinders, probably not too bad on the V8. I would not look at the MAF (unknown if it is a problem) until you replace the O@ sensors (known problem). Plus, if the MAF was bad, you would likely get an error code for that as well.

Good luck.

Steve

are there just two O2 sensors on the m60? one before cat and one after?

I just ordered both O2 sensors I will let you guys know if that takes care of the problem

Eagerly awaiting results

And yes, there are a total of only 2 O2 sensors on your car, one on each exhaust prior to the catalytic converter.

I got to looking and I think I might have ordered the wrong O2 sensors the part numbers I ordered are bosch 13523 and bosch 13522. I only see two sensors located on each of the exhaust down pipes? I don't see any after the catalytic converter anyone know if these are the correct sensors? it looks like the wiring connector on bosch 13522 is different than 13523. its a 95 540i I am wanting to replace all O2 sensors on the car

Where did you order your sensors from? According to autohausaz, those are the correct sensors for your car.

Originally Posted by ahults

I got to looking and I think I might have ordered the wrong O2 sensors the part numbers I ordered are bosch 13523 and bosch 13522. I only see two sensors located on each of the exhaust down pipes? I don't see any after the catalytic converter anyone know if these are the correct sensors? it looks like the wiring connector on bosch 13522 is different than 13523. its a 95 540i I am wanting to replace all O2 sensors on the car

ahults, as said before, there are only 2 sensors on your car. One on each downpipe as you stated. It is an OBDI car that does not use post cat sensors.

Dude, just had an idea. Disconnect the existing o2 sensors...just unplug the sockets from the wiring harness. The car will switch immediately to stored factory values....a backup typical map. This will not be as perfect as working o2 sensors, but will also not lead to running rich condition and you can drive your car comfortably. When you get the new sensors, you can fix them in and reconnect the sockets.

I ordered them from autozone but one says it is located after the cat but the only two I see are on each side of the exhaust down pipes before the cat. I thought there was only two O2 sensors located before the cat

Originally Posted by ahults

I ordered them from autozone but one says it is located after the cat but the only two I see are on each side of the exhaust down pipes before the cat. I thought there was only two O2 sensors located before the cat

Call them up and talk to a human, they are usually quite knowledgeable and always very helpful.

I got the right sensors I should have them installed by this weekend I'll let you guys know if it helps the rich fuel mixture

I wanted to let you guys know the O2 sensors fixed my rich fuel mixture, runs like a champ now, thanks for all your help

That's great champ. Now go for that WOT

Great Thanks for letting us know the results.