13 RMZ 450 Electrical Issues...

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4/19/2018 4:11 PM

Looking for some insight... I’m having some wierd electrical problems with my bike. It will not start. This happened completely out of the blue. Went from running fine to not running. I’m pretty good at electrical diagnostics but I’m lost now. It will pop when starting fluid is sprayed so I have good spark. I’ve tested every electrical component on the bike according to the manual. All peak voltage tests, input and output voltages from all sensors and continuity through the harness from all sensors to the ecu.. my issue is the fuel pump. I have 12v at the FP plug ( harness side) when a battery is hooked up to the service coupler. Problem is as soon as I hook up the fuel pump to the plug I lose voltage?!? Same happens with a test light. As soon as any load is applied to the fuel pump plug (harness) it loses the 12v... what is going on?! Fuel pump works fine on the bench with twelve Volts. I’ve tested everything... I need help.. please!!


4/19/2018 4:26 PM

Did you test the connectors themselves? What about undesired shorting when the gas tank is put on?


4/19/2018 4:43 PM

I even cut the old connectors off and put on new ones to rule out a bad connection


4/19/2018 5:20 PM

Sounds silly but if you can get your hands on another tank try swapping yours out or pull injector out of throttle body and see if it’s spraying gas maybe a bad injector if your spark is good..


4/20/2018 4:45 PM

I pulled injector out. It’s spraying when I ground the 10 pin at the ecu in order to get the fuel pump running. I was thinking my fuel pump relay was shot in the ecu... no go... new ecu.... same exact problem...


4/20/2018 5:04 PM

I would start replacing harnesses.

Not a dirtbike BUT, my truck had a problem with the fuel pump driver module. The module itself was bad, but the wrapping and wires like halfway up the harness were corroded and broken. The mechanic was able to pull broken wires to find the problem.


4/22/2018 6:04 PM

I would be suspect of the stator or condenser. I see it occasionally, stators can test fine when they are at room temp, but under heat or load, they can break down. The same goes for the condenser.

Suzuki harnesses aren't cheap(I'm a dealership technician). I had to replace one recently in a RMZ 250 and the owner was in shock of the price.