Check Engine Light after hard acceleration

[bignasty27]

Hi everyone!

Had my X's for a few years now and have always read and read this forum for valuable information anytime I had an issue or needed a fix. I can't seem to nail down what is causing the CEL after a hard acceleration.

Firstly, its 2009 4.8i. Few weeks ago I had the CVV changed due to heavy oil consumption. Fixed that issue so far.

Drove a week or so and everything was fine but after passing a car on the highway, the CEL lights up. Had my INDY (buddy) scan the computer and I get P2178 " System Too rich off idle ".

He reset the computer thinking that perhaps the system was compensating for a clogged CVV and now all the parameters needed to be reset. Cleared fault code and drove around for another week or so. Again, hard acceleration merging onto highway throws the same code. No code with regular city driving only when I give it some extra power.

I do experience a slightly low RPM at idle which I can feel in the form of a slight vibration in the steering wheel. Not a big deal and maybe its in my head.

Bought the truck off a relative in 2013 and have been relatively problem free since then.


Changed spark plugs a year ago
Used Techron cleaner last week

Based on what I've read in this forum, I will be looking into:

MAF
O2 sensors
low pressure fuel sensor
fuel filter


Any thoughts?

[absentmathis]

Unfortunately I can't offer any advice on your code, but I do have a question based on your comment about vibration. How smooth is your idle typically? Can you feel it in the seat and wheel at all? I've got an '08 48i and I don't think it idles well. All of my past bimmers have been so silky smooth that you have to look at the tach to be sure it's running. This one isn't like that. Normal?

[bignasty27]

I have a 2005 X5 4.4 and the idle on that is much better, like you don't know if the truck is running or not. I rarely get that with the 4.8i but most time I'm gripping the wheel feeling for the vibration and I can always find it. Its slight but it does bother me. I look for it in the 4.4 hoping its in my head or that it is normal but its smooth.

[absentmathis]

Yeah my e53 4.4 was much smoother too. Good luck with your issue. Of the things you mentioned I'd start with fuel filter.

[jfoj]

The problem with the fuel filter on the E70 is it is part of the fuel pump.

I have no hesitation in replacing the fuel pump at this age as I do not trust BMW fuel pumps to be reliable past year 8 anyway. The fuel pump was one of the first things I changed in my '08 4.8 E70 when I purchased it.

Also the fuel pumps are having problems with the connector pins melting anyway, just search and you will find some good examples with pictures.

As for the code, I have not see this, but most vehicles have a hard time running Rich. Most things as they degrade lead to Lean conditions.

Suggest you invest $30 or less in your own OBDII scan tool. Get OBDFusion for your phone or tablet, this is less than $10, then get the appropriate wireless interface. Then you can actually Log things like Fuel Trims and Engine Fuel System Status to see what is going on. If you know what to look for, you can even see how healthy the catalytic converters are.

One thing I recently found is these vehicles WILL NOT give an indicator at all when the alternator is not charging. You can use this App to monitor Charging Voltage, but suggest you read this thread to see what I ran into -

http://www.xoutpost.com/bmw-sav-foru...tem-issue.html

You need to gather data and analyze what is going on and hopefully this will lead you to a conclusion as to what may be happening.