I am actually doing this upgrade tonight ..... I will post pictures of my charred (and melted fuse holder later).
This circuit is a weak link in the 930 wiring design.
It is horribly overloaded and any resistance in the circuit sets up a scenario like you described.
930 fuel pump relay wiring - once and for all
Cliffs .....
There is a red wire running between Pin #30 on the two fuel pump relays. Find it. Cut it.
You are now going to install 2 blade fuses (one per relay) at the cut.
The other end of each fused wire runs directly to the battery.
Clean up the #16 fuse (OE fuse) wiring.
Photo credit goes to Jeff (Sand-Man) .....