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Fuel Pump Connector Voltage? (Lower than at battery terminal)

3K views 8 replies 3 participants last post by  linkmodo 
#1 ·
Howdy... So after putting the bike back together after some maintenance work today, I started the bike and heard no sound coming from the fuel pump... No Bueno...

My first thought is that the darn fuel pump somehow got broken from me moving the gas tank? I ordered an aftermarket fuel pump to come in since genuine one costs $200+...

Out of curiosity, I checked the voltage on the fuel pump connector, it reads something like 11.25v when the ignition is turned on (0v when ignition off). And I tested battery voltage, the battery is at 12.85v

Is the fuel pump connector supposed to have a voltage drop of over 1.5v? If not, what could be the cause? Dirty terminals? I just fixed a terminal issue and this new problem popped up...
 
#3 ·
.... I checked the voltage on the fuel pump connector, it reads something like 11.25v when the ignition is turned on (0v when ignition off). And I tested battery voltage, the battery is at 12.85v ...
Not with your ignition on I would bet ......
1. Measure your battery with your switch on and compare again
2. Measure the voltage at Fuse 5 (just touch your probe to one of the metal tabs on top of the fuse) - compare that wit your pump voltage

Bottom line - there's nothing wrong - you are just measuring voltage drop due to a) normal loading of battery (particularly because of headlights) and b) current flow down the ignition circuit creating a voltage drop in that circuit

I started the bike and heard no sound coming from the fuel pump... No Bueno...
Not following here - do you mean you STARTED the bike .......... or ATTEMPTED to start the bike?

If it started then clearly your pump must be running
 
#4 ·
Not with your ignition on I would bet ......
1. Measure your battery with your switch on and compare again
2. Measure the voltage at Fuse 5 (just touch your probe to one of the metal tabs on top of the fuse) - compare that wit your pump voltage

Bottom line - there's nothing wrong - you are just measuring voltage drop due to a) normal loading of battery (particularly because of headlights) and b) current flow down the ignition circuit creating a voltage drop in that circuit



Not following here - do you mean you STARTED the bike .......... or ATTEMPTED to start the bike?

If it started then clearly your pump must be running
Sorry for my English... I turned the ignition to ON position (ready to push the Start button) and took measurements at fuel pump connector and directly on battery.

When I tested the voltage I had the headlight fuse unplugged, and I have LED bulbs in the taillight don't think they draw that much current. Will test fuel pump tomorrow by hooking it to the battery with some wires and see if it spins or not.
 
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