Originally Posted by ///M Ryder
This is total BS......in fact my Cooper S went in for a CEL a couple of months ago. Problem was dirty injectors. They hinted that maybe it was some dirty gas. I say bullshit....I've been getting gas at the same station for over 6 years. I've never had a issue with any of my other BMW's. Turns out this SA was a noob. The issue is a common issue on some turbo set ups. This was all covered by the nice warranty we pay for in that MSRP price. Get your money back. You'll through a light if the problem is that bad..................Phil
Fuel injection service works 2 ways.... Additive to your tank part 1, part 2 remove fuel pump fuse, connect a pressurized container with fuel cleaner and let the engine run on it til the canister is empty. The solution in the container contains a heavy concentration of detergents that will release carbon deposits on the intake valves and pistons. It really does work. Most dealers use aftermarket injection cleaners like Wynns or BG. There is a oem solution available from BMW that is mixed with gasoline which is not covered by your maintainance plan. Aftermarket ones are better IMO, they remove deposits faster. The BMW one makes them more soft and gummy so you have to go it several times for the same effect. These engine all have integral crankcase systems so OIL is deposited into the intake manifold. As for cleaning the throttle plates, that part is BS. If you use cheap gasoline that does not contain several detergents you should do a fuel injection service more often. BMW recommends only Top Tier fuel. There's a list available from BMW if you don't know what brands they are. Poor carbon build up is most noticeable at idle and throttle tip in.
As for your Cooper S, it depends on the engine. If you have direct injection it will not be sprayed on the intake valves. They have designed a tool that sprays walnut shells on to the intake valves that removes these same deposits. Same problem with 335's. Don't call BS until you have seen it first hand.