At some of this summers cruises I noticed a slight fuel smell in especially in hot conditions, as has been many of this summer, and as this is somewhat scary and doesn´t improve fuel economy etc I tried to localize the problem and finally found a small leakage at the fuel pump flange see arrow below.
When trying to tighten the flange screws one of them failed as the housing seems to be made of aluminium. Had to repair the threads and retighten. However this didn´t fix the issue so I had to investigate further. Finally found that the lid and the pump housing wasn´t straight at the sealing surface and also had some pittings in the cast (Hmmmm…. I love the quality of replacement parts nowadays. It says “Made in Canada” on the pump but I doubt that….). To remedy this I removed the pump and using a fine sandpaper against the garagefloor sanded the surfaces to a good straightness and to a fine surface finish. See pictures below. Now the pump is tight and I also get a better starting response when the Caddy has been standing still in the garage for a couple of days as the fuel doesn´t leak back to the tank as before. Nice !