I had a strong smell of fuel coming from rear passenger side (more from the outside) and sure enough I had the infamous leak from fuel pump located beneath the passenger back seat. Although it has been described for 93+ E31, I thought I will post info for those of us with one piece back seats.
Jon Nelson in DC provided the technical guidance and John Fuston performed the repair with sure expertise. I can't thank these guys enough.
In order to get the back seat out, you need to first undo 3 philips screw holding the center rear storage space (one holding the medical kit). Then you need to remove the rear inside panel. This is held on by series of 5 clips at the base of the window and by 3 pop out rivets (green) along the front edge of the panel as shown below. You need to pull along the top edge straight in towards the center of the vehicle to undo the top clamps.
You are then able to undo 2 nuts holding the back seat in place along the top side of the seats. The entire seat can then be removed. The fuel pump is located beneath a round metal cover held down by 3 Philips screws.
When I removed the cover, a pool of fuel was found on top of the fuel pump assembly.
In my case, the leak was coming from one of two short fuel lines connected to top of the pump. I understand that you can also have a leak from the electrical connectors (to fuel sensor and fuel pump regulator) or from the fuel pump itself. Although the fuel lines are only ~4inches long and clamps are visible, it is impossible to get access to the other end of the line (the end that is not visible) without removing the tank itself. Quick call to Jon, and he suggested drilling a small hole on the floor to gain access to these clamps. So we drilled a 1.5 inch diameter hole on the floor and voila.
The fuel lines (5/16 inch ID) were replaced and no more leak. We were careful to mop up the fuel and even had a Halon extinguisher in hand as we drilled into the floor as a small spark could have easily toasted not only our car, but both of us as well. Also the fuel line holds a lot of fuel (several ounces easily). We even lifted the back end of the car up to reduce the amount of fuel that had to be drained.
Hope this helps anyone else on this board with a similar problem.
Richard
