Expert: John Kingery - 10/7/2008

Question
i have a 1997 bmw 523i.when it is ticking over at traffic lights etc there is a strong smell of petrol.i have checked for leaks but have found none.help.

Answer
A couple of things to check.

1.  Does your car drip any fluids.  Check if you are dripping gas when you stop.  If not, it's likely not coming from your fuel lines.

2.  your fuel pumps and sensors are mounted to the top of the tank, which is directly under your back seat.  Remove the lower cushion, and see if the smell is stronger.  Might indicate a leak at one of the connections there.

3.  strangely enough, sometimes this occurs with the sunroof open.  the vacuum created pulls the air up from other sources, including via the rear seat, and the fuel from the seepage at the tank can be smelled.  See if it's different with your sunroof closed.