[B]Help!!! Could IBS Sensor Cause Engine to Knock!?

Do any of you have experience with a faulty IBS Sensor? My motor will randomly knock and choke and bog down, service engine light comes on and iDrive says Increased Emissions! Tachometer needle stutters with acceleration and motor shakes. It'll randomly occur and then drive funky for a day or two, only to clear and drive fine for a few weeks! Stealership says IBS Sensor, wants $600 to replace and recommends new battery(for $450), I've never had any electrical problems! Any ideas?


Thanks!!!

This sounds like a pretty significant issue; you're not going to diagnose it completely on a forum. That said, e60s are very battery dependent, and thirsty for lots of clean power. Besides IBS issues (which would confuse the car on its charging strategy), a weak battery (or alternator with low output) can cause a variety of run-time issues. Try to get all of the run-time codes that the car is showing, and get your battery and alternator tested at Autozone.

Ok, thanks for the advice. Autozone is a good idea. Hey real quick, you said get all the run time codes...I am pretty good with mechanical stuff, but this is my first BMW and the computer stuff is new. Can you give me alittle more detail on how or what to do for run time codes? I have the Bentley Published service manuals, and I know how to get into the hidden menu's. It is just crazy how well the car will run and drive, and then all of a sudden go berserk. Only to clear within a day or two. That was the problem with the dealer, I took it to them the same day it did it, but by the time they got to it...6 hours later...the codes had cleared. I really appreciate your time and knowledge. I love this car!

The codes will not clear themselves in the cars memory. When an event happens, a pre-code appears first (kind of a notice that something is approaching limits) and then a code. Both are registered. Most commercially available code readers (like Centech and others) will read the codes, but I caution you: A code that specifies an emissions part failure DOES NOT MEAN that the specific part failed; many times it will simply be related, and something that caused the other component to provide data improperly (garbage in-garbage out theory). If you're not an experienced mechanic, don't mess with it; it's just not a home-level diagnosis without a lot of experience, a laptop with INPA and the patience to individually test parts. Find a good independent mechanic- He'll do the diagnosis far cheaper than a dealer, as will be his repair.

Fair Enough, I'll take it to an Indy I was recommended too. I don't understand why the stealership told me the "codes had cleared." I'm just eager to learn and be able to fix things myself. Bavariantechnic.com has the diagnostics i plan to buy. But for now, I gotta do what I gotta do. Thanks for your help man, Its much appreciated. I like what you've done to your 550i, impressive.


Luke