V8 blowing fuel pump fuses???

My v8 failed to start on petrol today ( it has a gas conversion which it runs fine on) i noticed the fuel pump wasn't priming when ignition switch was turned. Found the fuel pump fuse was blown. Replaced it and it blew again. Even blows with the fuel pump plug disconnected on top of the tank. Any ideas? Happened to anyone before? Could it be the relay or is there a common wiring failier point?
Any input would be great...
Andy

Just got sameish problem just done my clutch and now blowing fuel pump fuse confused.com did you have any joy tracing problem thanks Mike

There's outputs from the fuel pump relay to both oxygen sensors so an iffy one or wiring to it will blow fuse No6, which is also the fuel pump fuse.