Fuel Pump Fuse keeps blowing?


99 Busa with external pump assembly.

I was working on it today and replacing and rerouting the fuel lines because I thought my fuse blowing problem was a line getting kinked, thus causing the fuel pump to demand too many amps and boom, blown fuse. Well one of the lines was pretty damn kinked, so I'm glad I replaced them, but I started the bike with the tank half propped so that I could check for leaks or potential kinks. Starts and runs fine. Set the tank down and she dies - blown fuel pump fuse. I double check to make sure there are no kinks, none. New fuse - blows without even starting the bike. (blew with key in ignition, turned "on", kill switch on the whole time) This tells me it's electrical, not a kink.

I thought maybe somehow my nitrous solenoid (right next to the pump) was contacting the connections on the FP or grounding out the fuel pump somehow, so I took it off. I had to raise the tank to do this. put the tank down and it starts with a 15a fuse (my last fuse). I pushed on the tank, simulating road bumps moving wires and lines around and she dies - blown fuse.

A tipover or kickstand sensor malfunction would just kill the bike, right? Not blow a damn FP fuse.

I wanted some thoughts before I rewire this damn fuel pump straight to the relay. (FP to relay to ECU, bypassing all the potentially faulty connections)


tipover, or kickstand error would give you an open, not a short.

your circuit is taking a shortcut to ground ...


Donating Member
tipover and/or sidestand wouldn't cause the fuse tp blow for the fuel pump. I would retrace the wirring again. If you've got an OE pump on there then it shouldn't be blowing the fuse.



Replaced the lines today.
Replace the fuel, just in case.
Replaced the fuel filter, just because.

It ran but not well at all. If I put any type of stress on it, rev or put it into gear or anything, it'll sputter the die. At idle, the entire bike's electrical system was flickering with the RPMs, which I guess makes sense since it's barely running. This was odd though because it likely wasn't electrical; I had it hooked up to my car battery to be SURE to get 12v.

Good news is I'm not blowing fuses, so I guess I've fixed the short.

I pulled out the multimeter and tested everything fuel related. Results:

Battery ~12.3x with bike off.
The fuel pump power wire is connected via a 4 to 1 connector, connected to each injector. At that connector (so pump and injectors) I have 11.89v during prime (with key "ON" bike off) and 11.89v with bike at idle. So those are getting power when they should.

At the relay:
I have 11.89v on one wire, constant. (12v battery lead)
11.8v going to the fuel pump during prime and at idle.
11.8v going to the two other wires once the key is turned "ON", and remains constant through idle and 11.8 while running.

All my voltages look fine, so I guess I need to look at actual flow of fuel, faulty fuel pump (but there is a different code for that), ECU problem, or...I dunno.


i have the same probleem with my 2000,but after a few minute i didnt hear the fuel pump relay click. i check all the wires and plugs for poor connection,i change the relay with a new one but i still have the same probleem. can someone help me??? im sorry about my English,i am from Curacau

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