Hi, I had a problem with my Z4 about a year and a half ago where one day on start up the engine was hunting very badly and had no throttle response when throttle was pressed. This was renewed by a main dealer which cured the problem at the time, however 2 weeks ago this problem re-occured with exactly the same symptoms but this time I went to a BMW specialist in Chelmsford who diagnosed it as a throttle pedal fault. After part came in from Germany 3 days later the garage fitted it and then told me it was the throttle body which is kind of what I said when I gave them the keys. After speaking to BMW they said there was a 2 year warranty on the repair so after paying a £95 diagnostic fee to the specialist I then paid £80 to get it recovered to BMW who after having it a week said it needed a throttle body which they fitted today which has apparently not sorted it. They have now come back and said it needs a engine harness as according to a Bulletin is the cause of the problem due to high resistance on the pins on the throttle body. I have questioned this diagnosis as I do have some technical experience although not on BMW as I would have thought you could tweek a connector pin to obtain some sort of change in the fault. BMW say they have done this but has made no difference. They now want another £90 for diagnosis and £650 for a harness which I am not convinced it needs and even less convinced after the workshop controller seemed unsure himself when questioned. Sorry to go on but I am banging my head against the wall with these Chimps so would like to know if anyone else has had this fault and cured it or has a copy of the Bulletin or has a Wiring diagram I can look at as I would like to carry out checks myself should it come to it although after speaking to the workshop controller I think he is double checking the diag. Thanks if you read all this - Dean.
