Hi, UK owner here - I tried what I think is the main UK forum but haven't had much of a response. I'm sorry that my first post here is to ask for help, but my wife's 2003 100k mile Copper S R53 has developed a fault. I don't drive it much but did last week and noticed the issue below (she drives like Miss Daisy so I can understand why it hasn't happened with her driving).

Under hard acceleration, in 2nd gear and up to 6,000rpm the car will suddenly lose all power, switch into limp mode and dashboard lights up. The car will run again after restart but the amber CEL light will remain on. This will reset overnight or (it seems) when I look into the odometer error codes - which just say '0000000' so no fault codes showing on the odometer.

Last week our local indy BMW specialist plugged in his OBD, found a code, apparently tightened/reseated a loose air pipe and road tested it and said it was okay. And charged £45.00.

But the problem hasn't gone. I took it back today and he can't tell me the code (he says he can't remember) and wants me to book it in and pay more for further diagnostics. He said it could be anything and the codes don't always tell you what it is right away. I think I remember him mentioning 'MAP' and 'Pressure' and maybe 'Barometric' when talking about the code when I first took it there?

I was wondering if anyone might have had something similar and there's an obvious solution?

My wife said the car's had the same problem before and the previous receipt says the specialist 'supplied and fitted rubber air intake hose'. The specialist I spoke to today said they go soft and it was probably 'the thin one underneath which you can't see'?

I also feel the car is running sluggishly - I don't drive it much but seem to remember it being a bit more nippy than it feels at the moment.

Here's what I've done so far after researching threads here (mainly talking about replacing MAP sensor, t-MAP or bypass valve)...

- Fitted a new air filter as it's cheap and the previous one was filthy.

- Checked all visible hoses for splits and tightness - all seem good.

- Checked both MAP sensors and cleaned them with carb cleaner, but I know they could still be faulty. I've spoken to GSF (UK Parts supplier) who can supply a non-bmw MAP sensor (I believe the front 4 pin one) for £16 and I wondered whether to swap anyway just to check.

- The bypass valve has some tension in the spring (it bounces back but not exactly strong), and I've noticed it doesn't close completely to the stop.

Any help or advice would be appreciated before I have to book it in for potentially expensive hours of diagnostic fiddling around...

Many thanks

 

Hey RS,

When you lift the bonnet does the car have a burning rubber smell on the belt side of the motor?

I spent a few hurdred figuring out the OEM crank pulley was seperated inside. Bought a new NON OEM pulley I got from WayMotorWorks and it is running much better now.

 

Thanks for the reply. There is no rubber smell at all. I've read somewhere else about the pulley halves separating and will mark each side with Tippex and run the car to see if they stay in alignment.

Anyone have any other pointers? I'm still thinking a bad sensor or bypass valve...