95 740 iL engine light

[public1]

codes 1212 and 1213 are coming up. does someone know what needs to be replaced. i think it's O2 sensors, but i don't know which ones.

[jeffreyb4me]

could be the O2 sensors there is one for each bank but the problem could also be a common air leak caused by a failed 'crankcase pressure valve' in the rear of the intake manifold......any rough idling or blue smoking problems?..[mainly while warming-up]

[public1]

no blue smoke. i think it all started w/ low octane gas. it's been clearing up lately. the thing is that it idles fine and then a little while later it acts like a coil is breaking down and we;ve already checked all that. i did get those 2 codes though.

[jeffreyb4me]

i'll double check those codes in the morning, but even with no blue smoke yet, the symptoms are classic & 02 codes by themself won't cause the rough running you mention, the cracked control valve diaphram will. I'LL BE BACK!

[libertylover]

Here's a site with the fault codes and how to read them (on E32 models).
http://www.pelicanparts.com/bmw/tech...de_Reading.htm

[jeffreyb4me]

dear john [funny?], anyway, as i thought, your engine codes are both for the 'left bank', #1212 is an O2 sensor fault BUT probably reads out as short to B-, because of #1213 which means the mixture is out of range, probably lean. like i mentioned, the most common failure as that cover on the rear of the intake but the intake manifold seals can leak as can the camcover gaskets [if high enough on the cover they won't leak oil, just suck in unmetered air, hence the 'LEAN' condition. find the cause of the LEAN condition, repair it, clear the codes, then see if the O2 code [1212] comes back. if so, only then replace the left side sensor..........
fun to you........jeff

[public1]

jeff, i appreciate all your answers and will proceed as you've instructed. thanks for all your help. Johnny p.s. let me know if you ever have any odd problems yourself. i'm good with a lot.

[jeffreyb4me]

K.O. johnny.........have fun....................jb.

[richlove]

I have a 1995 740i.
I am wondering if I might have a bad crankcase pressure valve.
I don't have any engine lights coming on but...
My symptoms are that the engine idles roughly for about 30 seconds when first started in the morning, then every thing is fine after that.
But during the rough idle, there is light gray smoke from the exaust.
I have owned this car since new and it just started doing this a couple of weeks ago. 136,000 miles.

If I need to replace the cover on the back of the intake manifold (I assume that this has the crankcase pressure valve in it) , can I replace it without removing the whole intake manifold?

Thanks,

Rich

Originally Posted by jeffreyb4me

could be the O2 sensors there is one for each bank but the problem could also be a common air leak caused by a failed 'crankcase pressure valve' in the rear of the intake manifold......any rough idling or blue smoking problems?..[mainly while warming-up]

[jeffreyb4me]

It's possible, early stages of failure, but there are a host of other possiblities and in some cases it's easier to daignose as the symptoms get worse.

Try this if you can. The next cold start, have the hood open and while it's still running rough, pull the dipstick out. If that valve [diaphram] is leaking you'll hear a suction sound and the engine character
will change.....opening the oil fill cap is a better test
but be careful as the chain sprocket underneath it will be throwing a lot of oil around, [open it just slightly away from the cover]

in the meantime, when did you last have a major or Inspection II service performed?, have the cam covers been resealed yet and have you noticed any sudden increase in oil consumption?............jb.

[richlove]

I had an inspection II several years ago.
Don't know if cam covers were resealed.
Are you talking about the two valve covers or are cam covers something different?
No increase in oil consumption.

I will try the dipstick trick in the morning.

Rich

Originally Posted by jeffreyb4me

It's possible, early stages of failure, but there are a host of other possiblities and in some cases it's easier to daignose as the symptoms get worse.

Try this if you can. The next cold start, have the hood open and while it's still running rough, pull the dipstick out. If that valve [diaphram] is leaking you'll hear a suction sound and the engine character
will change.....opening the oil fill cap is a better test
but be careful as the chain sprocket underneath it will be throwing a lot of oil around, [open it just slightly away from the cover]

in the meantime, when did you last have a major or Inspection II service performed?, have the cam covers been resealed yet and have you noticed any sudden increase in oil consumption?............jb.

[richlove]

Jeffrey,

I think you nailed it with the cam covers.
I replaced the spark plugs and noticed that there was oil on the plug closest to the firewall. (Enough oil on the insulator to cause a problem when cold). I found out that the cam cover bolts were loose and most likely the cause the the oil leak.

BTW, I did the dip stick test and heard no suction sound.

Maybe this will solve my problem.

Thanks,

Rich

[jeffreyb4me]

hey Rich, while loose cap screws may be the cause of the leakage, the rubber gaskets them selves harden over time and no longer seal well. they seem to last about 80,000 miles.....as far as the cause of your running problem, try what you've done so far and see, were the plugs fairly well worn?.......the thing is I've seen these engines with oil covering the tops of the sparkplug wells and they ran fine ! !....the oil does deteriorate the rubber boots and I always replace damaged ones but I've only seen running problems on engines with BADLY worn plugs and coil boots that were falling apart......best to you and keep posted please, jeff.