My PO171 & PO174 Journey
 

Well, at 150 miles on the trip odometer yesterday my SES light came on... again- same codes as before:

PO171 CNF - Bank 1 System Too Lean

PO174 CNF - Bank 2 System Too Lean

I've been using a couple of threads as a resource as I've tried to track down the problem(s) and in particular this one has been very helpful.

http://forum.e46fanatics.com/showthread.php?t=897616

So far I've done the following, all OEM:

Replaced torn intake boot, upper and lower replaced
Replaced MAF sensor
Replaced Fuel filter
Cleaned the DISA & inspected, ordered new gasket
Cleaned ICV

Then I got sidetracked when my car wouldn't start and replaced my failed fuel pump (see following thread)
http://www.bimmerfest.com/forums/sho...616&highlight=

After I swapped the fuel pump for a new one I reset the SES and at 150 miles it turned back on yesterday. I think my plan is to continue my journey with a CCV replacement. With 120k on the car I'm sure it needs to be done anyway but I'm really hoping that it fixes both my SES light and some low idle problems. The car idles significantly better than when I started this whole process but it still occasionally dips a little low at stoplights.

I think I'm going to order the cold weather CCV from OEMBimmerparts. They sell a kit that comes with appropriate gaskets and the vacuum lines as well as the CCV unit, seems like a good deal...

I'll keep you all posted and if anyone else has any bright ideas for things I should do well I'm in there I'd appreciate the advice!

On my M54, I had these codes for a year, until a smoke test tracked 'em down:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)
http://www.bimmerfest.com/forums/att...1&d=1341394328

Can you buy that orange gasket for the DISA at the dealer for the E46? We can't do that for the M54 so we have to second source 'em.

This is a good CCV thread if you're interested in testing it first:
- How to test the crankcase ventilation (aka CCV, CVV, PCV, CPV, & OSV) pressure regulating valve system (1)
http://www.bimmerfest.com/forums/att...1&d=1319901708

I ordered my DISA gasket from German Auto Solutions for my M54 motor.

I'm not too concerned with testing the CCV, I'd just like to replace it for peace of mind and to keep hacking away at the list of possible SES causes. I feel like what I've read regarding the CCV indicates that like other parts of the car it really is a maintenance item. I'm also afraid to touch any of the CCV hoses because they're so brittle, another reason to order the full replacement setup and swap it in.

Thanks for all the useful links, it is amazing how much information is out there about these cars.

This x1000. I just did this over the thanksgiving weekend and every hose associated with the system broke.

The hose that had failed on its own for me was the oil return hose that connects to the dip stick.

Good luck with the installation. Took me about 5 hrs.

Ah yes. That's where we get 'em also. We used to just buy o-rings to size- but that was before Gary showed up.
- Where to get just the DISA valve o-ring (1)

Understood. Too bad it's such a crummy system yet so time consuming to replace.
- How to do a CCV delete (1)

Smoke test is probably your best bet for lean condition misfires:
- How to make your own smoke machine (1)
http://www.bimmerfest.com/forums/att...1&d=1324209161

Same with me!

Dunno if the fact my double-walled dipstick tube was totally clogged had anything to do with the lower CCV vent tube breaking in half though ...
- How to test, clean, & redesign the original BMW dipstick guide tube to prevent CCV vent clogs (1)
http://www.bimmerfest.com/forums/att...1&d=1339367187

The TCV boot is also a common leak culprit on the M54 engine:
http://www.bimmerfest.com/forums/att...1&d=1338704950

Got started this evening pulling all the stuff out of the way that has to move to expose the CCV and hoses as much as possible and what do I find- a hose that is busted in half... Gonna get up early and bust out the rest of this job tomorrow but now I know for sure that this was causing problems. I'm amazed that it's just busted in half...

And Done!

It took me right around 3 hours total but it helped that I was familiar with pulling most everything on the driver side of the motor from cleaning my ICV and replacing my intake tubing. I had also done my OFHG previously and let me tell you, THAT is the time to do the CCV. Everything would have been out of my way to make the CCV swap and hose connections much quicker when doing the OFHG as well. I did end up removing my power steering reservoir just for some more hand space but I got it all snapped back together and then replaced everything and it started right up with no SES light.

I already notice a significant difference in my idle speed. The hose that was broken was the hose from the dipstick tube to the bottom of the CCV: I'm not sure how this impacted the CCV function etc. but I'm guessing it didn't help things and I'm hoping that it was the cause of my SES codes.

Now I've just got to get up early tomorrow and finish swapping my valve cover gasket to take care of my oil leak and I should be all set for a while...

Before you wrap everything up, check the very back of your intake manifold against the firewall. You should find one (or maybe two) rubber plugs that seal off vacuum nipples on the manifold. They're probably brittle and might be cracking. Replace 'em while you're in there.

See this diagram on realoem.com, part numbers 17 and/or 15.

Well I screwed myself: the gasket was so brittle and baked onto the valve cover that I broke the cover. I'd been working on it for over an hour and I was on the last round gasket in the middle of the cover when I broke the thin plastic wall of the cover that the coil sits against. Ordered a new one and covered the whole motor up with blue shop towels until I get my new one. Sucks but I guess that's part of the DIY journey... Hope I get it Tuesday so I can put it back together.