Rough running - fault code explaination please?

[L33 4.6]

Hi,
The X5 (2003 4.4) has develped a slight fault whereby at a steady speed the car "hiccups" and judders slightly now and again. The engine management light flickers and sometimes goes out and sometimes stays on.
It does feel like a coil pack breaking down, although my only experience of this is coil packs breaking down under heavy load - not keeping at steady speeds.

I have had the fault code read and it states "Too rich bank 2".

Can anyone tell me what a likely fix would be please? I guess too much petrol is coming through to bank 2 or something is causing the fuel not to burn efficiently and a sensor is picking up I have unburnt fuel passing it and flags up a fault.

Either that or a sensor somewhere else in the engine compartment is playing up and asking the fuel pump for too much fuel...

Its not all the time and worse when the engine is cold.

Cheers,

[Wagner]

My guess would be oxygen sensor related, but it could be multiple items. Take it to a dealer for diagnosis.

[L33 4.6]

Thanks for the reply.
I don't fancy the dealer route. £135 per hour labour charge and the last service they charged me for a set of spark plugs which they didn't even replace!
My searches lead me to the O2 sensor but I can't find any info regarding how to change them. Is it easy? Do I need any special tools? and where are the O2 sensors located?
Many thanks,

[Wagner]

The reason you want it diagnosed is there are before and after catalyst sensors on the X5 (4 I believe total). Each costs roughly $75-$85 USD. As far as special tools go, I haven't changed one on a X5 before but usually standard mechanics wrenches will do the job, however some O2 sensors have the need of a special tool. Just go under your X5 and take a look before and after the catalytic converter.

Plus, if it is the O2 sensor, judging by the age of the ride it will be nearly impossible to get off. And if you do all that and it wasn't the O2 sensor, you've spent a lot of time and money on the wrong problem. Maybe you can find a cheaper BMW specialty shop to diagnose for you

[yenanx5]

Originally Posted by Wagner

The reason you want it diagnosed is there are before and after catalyst sensors on the X5 (4 I believe total). Each costs roughly $75-$85 USD. As far as special tools go, I haven't changed one on a X5 before but usually standard mechanics wrenches will do the job, however some O2 sensors have the need of a special tool. Just go under your X5 and take a look before and after the catalytic converter.

Plus, if it is the O2 sensor, judging by the age of the ride it will be nearly impossible to get off. And if you do all that and it wasn't the O2 sensor, you've spent a lot of time and money on the wrong problem. Maybe you can find a cheaper BMW specialty shop to diagnose for you

Bank2 sensor1. Is it before or after the catalist?
Thank

[Weasel]

Before. On the drivers side if it's a V8.

[yenanx5]

Originally Posted by Weasel

Before. On the drivers side if it's a V8.

My car is 3.0 i6, So it should be after catalist, am i right?
Thank you

[m5james]

The pre-cat sensors are the ones that feed the ECU information in regards to fuel mixtures. The post cat sensors are the ONLY to verify that the catalytic converters are in fact there and have no affect on performance.I also stay completely away from the stealership also....that defies the whole point of these messageboards. While the 4.4 has been in the X5 since 2001, us 5/7 owners have been dealing w/ it and its known issues since the mid 90's. While some of this is clearly 7 specific, much of the motor info is usable for all V8 owners...e38.org BMW 7-series information and links. I'm replying via my phone, but I can almost guarantee there is a write-up w/ pics on how to replace them.I had 135k on my 02's before I replaced them, and they weren't hard at all to remove. There is a specialized socket that used to remove them....if you can't access them w/ a normal wrench. I've never done them on the X as of yet, so I don't know what it looks like under there to access them. The special deepsocket has a goove down the side for the wire that connects the 02 to the ECU. I'm assuming you don't have Autozone (carparts) in the UK, so I'd go online to places like Auto Parts at AutohausAZ - OEM Auto Parts - Discount Replacement Parts, Resources and Car Care Tips. I got my last set of 02's for my 7 from Autozone, and they were in the $80 range. Make sure that when you install them that you apply anti-sieze compound.