Expert: Josh Fields - 3/26/2006

Question
Hi Josh,
I have had an O2 sensor/engine light problem that won't go away on my 95 525i.  So far, I've spent nearly $3000 on this problem to include replacing the catalytic converter.  Just last week, the BMW dealership modified the 4th, or maybe it's the 5th O2 sensor before they replaced it.  Unfortunately, 88+ miles later the engine light is back on, although the car seems to run fine.  

I have noticed the smell of fuel inside the car, and passengers have noticed the smell of fuel, too. Is it possible that a bad fuel pump could ruin the O2 sensors?

Thanks for your help.  

Answer
Teresa,
 I wish I could help you further, but what I told you previously was all that I know.  Sounds like you have an electrical issue, like the computer is FALSELY telling the light to come on.  
 Does the car run worse since the light came on (after 88+ miles)?  If the car runs fine you can do this:

 (1.)  Have a new ECU installed to see if it corrects the problem of the light.  This will be VERY expensive!

 (2.)  Drive the car with the light on.  I dont know what else to tell you, except your dealership guys dont want to mess with it, and they like your money.  So if they can keep you coming back for everylittle thing then that's money in their pockets.  A qualified, discaplined mechanic who is out there to do a good job (they do exist believe it or not) and save you money would not have let the car leave until EVERYTHING was fixed correctly.  I understand that the light is not coming on until some miles are driven, but there is OBVIOUSLY a reason for it, and it CAN be found out.

 My guess is to get all the details about what has been done to your car, take note of them and take the car to another repair shop.  Make sure you give all the details of what the car's symptoms are and what has been replaced to the new shop, that way they can pickup where the other shop left off, and they wont waste time doing the same things the other shop did.  Its unfortunate, but it sounds like you are being taken advantage of.  

 Hope this helps,  Good luck
 Josh