I NEED YOU GUYS HELP ON THIS ONE.
I HAVE A 1980 900 TURBO. IVE BEEN HAVING PROBLEMS WITH THE FUEL PUMP FUSE. I REPLACED THE FUEL PUMP RELAY AND IT DOESNT HELP. EVERYTIME I TRY TO TURN THE IGNITION ON I BLOW THE FUSE. I TRACED ALL THE WIRES RELATED TO THE FUEL PUMP AND I CANNOT FIND A SHORT. ANY IDEAS ?

 

Have you tried to see if the wiring has a break in the insulation and is grounding to the frame? Other wise it sounds like the pump itself is shorted out inside and causing the pop. easy way to check- disconnect one of the fuel pump leads and see if the fuse blows. If it doesn't, it's probably the pump. If it does, that is going to require looking at all the wires running from the tank back to the switch. Star with the wires running from the tank first. (start with the easy part). Also if you do find one spot grounding, don't assume it is the only one. check the rest of the wire run to make sure there isn't a second (or third) break in the insulation. Good Luck.

 

This is good advice. One other approach, assuming the fuel pump is not shorted internally, is to run a line/wire directly to the pump froma +12 volt source. It would help if you have a Bentley or Haynes circuit diagram, so you know which terminal on the pump is +ve and which is ground. That way you can take the existing wiring harness (with possible ground faults) out of the circuit.