Stinky-Poo! Bang! 6 January 2017  |  BigMick

Affecting: Cinquecento & Seicento

It's that stop-motion frame of Wile E Coyote just before the explosion that always raises a grin with me. Not so funny if it's in your Cinquecento or Seicento. fairly common fault this one. So much so Fiat were changing tanks under warranty. If you have a late Sei check with your Main dealer, they will have a record of whether the tank has been replaced yet. For older Cinq's or Sei's with that worrying fuel stench, check the tank for tell tale streaks. It's usually obvious. If there's clearly signs of fuel escaping, get the tank changed asap. If nothing seems apparent it's well worth pulling up the rear seat and removing the triangular inspection plate. Underneath you will be presented with the fuel level sensor and the fuel pump tops. Check for any dampness. This may not be blatant, On mine it only appeared after a couple of miles with a 3/4 full+ tank and it was a pretty minimal leak, but enough to make any journey a psychedelic experience.
Try renewing the sealing gaskets or sealing the original ones with a thin skim of fuel resistant jointing compound. (worked for me). Other possibilities are a poorly sealing fuel cap or breather pipe connections.