Geeez, this is like Yogi Berra and the "de ja vu all over again" thing...

I just got my 107 back from the shop for this same issue. Ran fine for sevaral years and then would not start in the parts store parking lot. I replaced the fuel pump relay (always carry a spare), no dice...replaced its fuse, no dice...finally admitted defeat becasue it was 95+ degrees and I was out of ideas ana patience. Embarrasing to see your SL leave on a tow-truck hook.

My trusted indy began to sort through the system and found a possible problem in the fuel pump wiring...PO had spliced in a kill switch to prevent theft. Fixed that wire but it still died when warmed up. The fault seemed to be related to temperature somehow...died when hot, cooled down a bit and would restart (but would not restart that very hot day in the parking lot.)

My mechanic noticed the main power fuse was an old replacement fuse, aluminum type. He replaced it with a new fuse, copper conducter, and no problem since.

Maybe your problem is in the fuses. I bought a stock pile of good quality brass/copper 8, 16, and 25 amp fuses and will replace all of the bogus el-cheapo replacement fuses tonight in both my cars.

By all means check the battery connection. There is a main power lead from the + terminal on the 107s; my indy looked there first to confirm it was solid.

Good luck with solving your problem.

230/8