Need help with codes?

Guys,

The car thew a couple codes today - PO171 and 174 for left and right bank lean. She's been driving fine (maybe a little down on power) and the only symptoms are rev on start and idles a little rough only at start up. Just started today and 80k on the odo. Where can I check and is this my O2's? Any advise is much appreciated.

Dave

Anybody?

Those two codes together often indicate a vacuum leak form a torn intake boot. Look closely for small cracks in the "bellows" part of the boot. If you can't see anything, try spraying a little carburetor cleaner at the boot while the engine is running. If rpm's increase, or become smoother, you've got a leak.

Originally Posted by jonathan2263

Those two codes together often indicate a vacuum leak form a torn intake boot. Look closely for small cracks in the "bellows" part of the boot. If you can't see anything, try spraying a little carburetor cleaner at the boot while the engine is running. If rpm's increase, or become smoother, you've got a leak.

Ok, thx I'll check the boot closely tonight.

start by checking the air intake hose for rupture. if it's ok, clean ur MAF.
if the problem persists, it would most probably be ICV.
i don't think it's an O2 sensor issue, since u'd be getting rough idling even when fully heated up.

Agreed, I completely forgot the car is still in open loop and during warm up and doesn't even take readings from the O2's yet. I'll check the intake boot tonight and see where my problem is.

Ok guys, quick update:

Checked the car last night to see if there were any tears in the lower boot using the carb cleaner method and sure enough, the idle would change ever so slightly (bump up) when spraying near the Y junction to the IAC. I've already spoken to my buddy that works as a BMW SA and she is going to see if they have any upper and lower boots in stock for me today. I'll let you know how it goes.

Well found my major problem:



Gotta order a new DISA valve. Oh - btw - if you are wondering where the flap is, don't worry I have it - it's not in the intake - LOL. Damn this sucks, car is down until I can get a new one in from OEMBimmerParts.

Originally Posted by wdaveweaver

Well found my major problem

You 'can' repair the DISA with better parts than OEM:
- How to repair your DISA valve using titanium & aluminium machined parts and eliminate the chance of engine pin ingestion (1)

Otherwise, there is (apparently) only one manufacturer of the M54 DISA so the price is pretty well set. However, you can get the group buy price on the DISA here (which is the best on the net) from running /disa F3 in the bestlinks.

- Where to get a proper DISA valve repair kit (1) & how some jury-rig 'repair' a rattling DISA unit (1) (2) (3) & how the DISA valve operates (0) (1) (2) (3) (4) & how to test DISA operation (0) (1) (2) (3) (4) & a simple DIY to install an M54 DISA (1) & a nice DISA autopsy (1) (2) & a great DISA group buy (1) & how the disa valve o-ring fails (1) (2) & how it can reputedly cause all sorts of cold-engine rough idle problems (1) (2) & where to get just the DISA valve o-ring (1) & why you want to check the DISA at 100K miles or whenever the airbox is removed (1) (2) & why the DIfferenzierte SAuganlage ("Differential Air Intake") valve flap breaks (1), sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) & a well documented example of how a broken DISA flap can ruin your engine (1) & yet another seemingly complex set of misfire codes reputedly traced to a broken DISA valve (1)

Went fishing today and look what I caught!!!

Ok, finished her up last night and runs MUCH MUCH better. Went ahead and did the VC gasket while I was at it as well since she was leaking. Found out that it wasn't the parimeter of the gasket, but the spark plug well seals on the middle of the gasket since the valley or under the cover it was full of oil and as it over flowed it ran down the outside looking like a typical VC gasket leak. I just replaced these gaskets and the VC gasket a year ago and is this common for these to fail? Maybe the middle VC bolts loosened up or I didn't torque them properly last time. Just curious?

Haven't had a chance to take her out yet, but on start up and running for a few didn't see any leaks and idle was great. Hoping to drive her for a few to reset the SES light.

Ok, the car is running great and finally have my torque back. Question for ya, will the lean codes reset after a while or do I need to have them reset by a scanner? I've unplugged the battery for several hours, just haven't driven the car for more than 10 miles yet. Just need to know if I need to go get them reset at AZ or Advanced or if they will reset after some driving this week to and from work.