I'm a owner of a 850i, I took my car into the mechanic the other day because the car wasn't running properly. It turns out the car was only running on the left side of the engine. After the mechanic did some research he came the conclusion that the catalytic on the right side was blocked and therefore making the right side turn off. Is this true? he seems like a legit guys and comes highly recommended. He said once new cats are in the car will be running on all 12 cylinders once again. Let me know what you all think. Thanks!

sounds like it's in limp-home mode. Not that I know much more than that, but it's a starting point for you

could be that. I've had an older mercedes that stoped runing and wont go faster than 20 miles /h when the cat was pluged.

Check the Cylinder Identification wires they are connected behind the air filter housing and mass air flow sensors.

It "could" be that but depending on mileage it could also be the DK motors are clogged with dirt and need cleaned......is the EML light coming on? how many miles on the car?

Add to the "More Likely and a lot cheaper" list:

Spark plugs-- #6 and #12 have sensors in the wires
Ignition wires
Crank position sensor
Cam position sensor
Coil
Air flow meter

Items that MAY be a problem but MAY NOT be THE problem:
Fuel pump--Won't run by design if any of the above have failed on that bank!
ECU--Usually with melted coil

If there ia a lot of cold air coming out of the dead side exhaust then a clogged cat isn't the problem. And a just non-performing cat won't shut off one side of the motor by itself--all of the engine control monitoring is done before the cats.

Start with the cheap stuff - use OEM style Bosch spark plugs these engines seem to have problems with Platinums.

Nice, thanks for all the information guys. I'm currently having the shop change the plugs. That was my best guess. The car was sitting still for over 1 year before I bought it. So I'm going to be doing a lot on it to get it back 100%. It has 55,000 Km. Which equates to around 34,000 miles. It near mint condition. The mechanic said there shouldn't be a major problems with the car. Also he is changing almost all of the bushings since they are worn.

Ok the mechanic is starting to working the engine components of the car. He just finished replacing the entire suspensions of the car. This took 2 weeks due the lack of 8 series parts here. The were mostly special order from Germany. Now I spoke to him about what some of you said on this forum but he still believes it's the catalytic for some reason, and the exhaust is going under the knife later tonight. Yes over here they work through the night (Dubai). I am going to try and talk to him before this is done and have him change the plugs. What else do you guys think it might be??? I'm open for any suggestions and I'll be sure to take pictures and post up what happens.

If he thinks its the cats then disconnect the exhaust and see if she runs on that bank.........if not try CPS, coil swap, MAF swap and check the wires.......

Success!! We got the car running right, It tuned out being a fuel pump. Who would have guessed? I thought it wasn't working because of a fault as you all advised me. Man I pissed off the mechanic when I came to him with my own personal points. lol. Turns out he ended up finding it out with out me. haha. Ah well what can you do? I went to shop to get an update and the newest update is the brake booster needs to be replaced... What are your guys thoughts on this? easy? hard? I saw where it is and it looks very difficult to get to. Also i'm planning on taking out the catalytics, will I get any performance out of this? Also what about sound? Sorry if i'm throwing out a lot of questions but I'm new to this whole V12 thing. I'm used to the BMW V8's haha.

Becareful about V8's.

Brake booster replacement is a 30 min DIY job and the part is not expensive........one of the easier jobs...

is it easy??? wow they did it actually. They said it was very hard. haha. And the parts from the dealer was nearly 800 USD. Maybe we're talking about different parts. I think it was the Brake Master cylinder that went bad in my car.

....It near mint condition....

This is a great forum and I can not only learn about bimmers but also some more English.
I alway thought "mint condition" means "almost like new".
A car with 55.000km, complete worn out bushings, one cyl. bank not running, brake booster shot - what comes next? I have to admit that I'm quite shocked that a BMW with such a low mileage can have so many defects :eek:

Good luck with bringing it back to a state where it should be. If I can be of any help with getting parts from Germany let me know. I get between 10% and 20% discount from my local stealer.

Cheers
Wolf

This is a great forum and I can not only learn about bimmers but also some more English.
I alway thought "mint condition" means "almost like new".
A car with 55.000km, complete worn out bushings, one cyl. bank not running, brake booster shot - what comes next? I have to admit that I'm quite shocked that a BMW with such a low mileage can have so many defects :eek:

Good luck with bringing it back to a state where it should be. If I can be of any help with getting parts from Germany let me know. I get between 10% and 20% discount from my local stealer.

Cheers
Wolf

yes this came as a surprise to me as well my friend. I found out the car has been sitting in a garage for maybe 5 years! not even driven once. So i'm guessing all the fluids thickened and rubbers became old, etc. oh well I like not to think about it really. I paid a lot so far and get it back tonight! haha. it's worth it to me. And thanks Wokke I do need something from you. I need all the performance chips for my car, shipped to Dubai. Let me know my friend. Thanks!

Sounds like you are talking about the brake accumulator which is $$$...........however this usually shows up as a fluid leak at the bottom of the accumulator which is "usually" a $0.30 Oring which can be replaced to solve the problem........this is a PIA job but saves major $$$$....

I agree with Pumped! It's a pain but you can do it yourself and save a bundle.

Thanks guys, you guya on here a very helpful. I actually ended up grabbing a entire system from the half cut I bought and the car is now fixed. In regards to why this car had so many problems I asked the mechanics and they explained each one out to me. ... the fuel pump... the plastic intake piece on it simply hardened and broke off. Which this cut fuel to one side of the engine. Also keep in mid this happened 2 days after I bought it. So i'm guess from not being used and then being used all of a sudden put some stress on the plastics and it just fell off.

Suspensions, basically the same theory I had. The rubbers hardened and simply cracked or became old. And the brake booster they couldn't tell. But I'm guessing it was the simple gasket for .30 cents that went bad as it's also rubber. everything is great with the engine and body, and tranny. So I'm happy. Not one to complain about money. Only because whining won't fix things. haha.

I was driving it today and man this car has soooo much torque once it's rolling if you turn off the ASC and hit the gas the back end will slide out... well atlast over here... because thee is sometimes a thin layer of sand on the streets ahahaha.

That's great news! Glad your up and running, Thanks for posting the fix results.

thanks man. Hey are those your 8 series on you signature??? Really nice man. Are they lowered at all?

Yes there mines and thanks! The one to the left is lowered 2 1/2 inches in the front and 1 inch in the rear! To the right is 2" in the front and 0.8 in the rear.
http://img99.imageshack.us/img99/452/recentpic3qm0.jpg

http://img79.imageshack.us/img79/8849/bam0ff4.jpg

Nice! I love it. You need to post up some pictures bro. And what type of suspensions did you go with?

To the left I have CSi in the rear and H&R in the front, Bilstein Struts all around. To the right has Eibach all around and Bilsteins also!

Brake bomb can go at any time..........mine went bad with less than 25k on the car......

Ryan....Did you go through the wheel well or took the light pod out to do that. I'll do mine soon and would like your experience on this. I already got the O ring fix done on the accumulator. The take out and put back was really hard (Time consuming and bending my body to go under the steering) but replacing the O ring was a breeze.

Faisal,

I did mine and it took an hour since Dinan used some of the mounting points to reattach/relocate the airboxes for the TT models and this made it a little more difficult for me. On a "normal" location you should go thru the wheel well and it should not take more than 30 mins...........make sure you depressurize and have the correct size flare wrench for disconnecting the lines (cant remember the size offhand).........really easy job and makes a big difference if you need an emergency stop............did not lose very much fluid either......

Thanks man. Yes...Mine is in the "Normal" Location. :)