[jharshman]

Looking for some suggestions on my problem. I replaced my alternator, had to pull the intake manifold back to make room for the extraction and install of the alternator. Seemed simple enough. Now it's got a rough idle and throwing three codes: manufacturer control (P112F), system too lean bank 1 (P0171), and recently (P00BC) popped up in the mix. I replaced the intake manifold gaskets - no change. Also replaced the stock charge pipe with a CTS unit (I cracked the stock one at the manifold flange while working on it...). Didn't touch anything else so not sure where to look next. Otherwise car is completely stock with 67k miles. Any advice on obvious things I may have boogered up while messing with the intake manifold?

[thejeremyman9]

Orings are good on the CP top and bottom? Vacuum line reconnected to CP?

[jharshman]

Yep o-rings were good. fit snuggly. My stock CP had no vacuum lines to it. New CP wears a cap at one port and a plug at another which I assume other models utilize.

[jharshman]

Update: took it to a friend's shop yesterday and he hooked up a smoke tester. Found a leak on the boost side charge pipe (which I had not touched at all). Parts are ordered so we will see. It was an hour drive to his shop and other than rough idle, she ran good there and back.

However, a new problem emerged this morning. Tried to start the car and it ran for maybe 3 seconds and shut off. Tried again and ran for less than a second and shut off. The next try resulted in no cranking at all and warning messages on the dash: fuel system malfunction, and brake system warning.

Now it won't even connect to my code reader.

I'm afraid the little German gremlins may have taken the high ground against me...

[thejeremyman9]

You just messed with the alternator, how is the battery? The electrical "gremlins" can sometimes just be a battery issue

[jharshman]

Good idea. The battery sure seems to be just fine. It did get low-ish while sitting in the cold weather (while I waited for parts and also for free time to work on it) and I had to put a charger on it. Never dipped below 75% charge though. My "smart charger" is happy with the battery condition - all green lights.

[thejeremyman9]

What does a code scanner tell you?

[jharshman]

Unfortunately, with these new errors (fuel system & brake system) on the dash, it won't even talk to my code reader anymore. I don't have any bmw diagnostics software though, just a standard OBD code reader.

Sorry pics are so dirty... I promise my car really isn't that gross.

[thejeremyman9]

I wouldnt expect those codes to cause a failure to communicate with the car. So, it seems like something else is going on. When the alternator went bad did it fully discharge the battery?

[jharshman]

Funny thing is I don't think the alternator was bad to start with. This all began because I had a noise on the drive belt sounding like a bearing at the end of its life. Seemed to be loudest at the alternator. However, after replacing the alternator I still had the noise. So, idle pulley and tensioner got replaced and the noise went away. The story is a bit longer than that, and the alternator pulley still seemed less than perfect when I pulled it off, but basically no the battery was never fully discharged. And yes, I'm an idiot for not trying the easy fix first.

[thejeremyman9]

Well, unfortunately i dont think there's much more you can go without being able to connct to the car and pull codes. You may need to get a OBD2 dongle that you can connect to your phone to use a BMW specific app or take it somewhere that can read codes

[jharshman]

I REALLY appreciate your help in this forum. I found a local shop specializing in BMW's and it's getting towed there today. Maybe I'll get that turbo upgrade I want while it's there... In for a penny in for a pound?

[thejeremyman9]

Originally Posted by jharshman

I REALLY appreciate your help in this forum. I found a local shop specializing in BMW's and it's getting towed there today. Maybe I'll get that turbo upgrade I want while it's there... In for a penny in for a pound?

Either way let us know what happens

[jharshman]

Here's the latest - been at the shop a long time. They figured out the ground strap self-destructed which was what caused the car to go dead. Next thing they found was a crack in the intake pipe at the turbo causing a slight vacuum leak. And finally, the new Denso alternator appears to be overcharging slightly on occasion which has the effect of making the MAF go sporadically haywire.

Ground strap is replaced. Car runs again. Intake pipe is replaced. Also already replaced charge pipes on botgh sides of intercooler. Currently the shop swapping the old alternator back in to see if that resolves the voltage/MAF issue. Already verified MAF is good.

Fingers crossed we're getting closer...

[thejeremyman9]

Thanks for the update, i have actually heard of a few ground strap problems recently. Where was the ground strap you replaced?