New issue 929
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Joined: Mar 2009
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New issue 929
OK new issue Still cant get power to fuel pump so I bypassed it. Does the fuel pump need constant prime? I run it to a switch prime it it starts and run then dies. Then I tried it when it starts to die I prime it again and it runs strong. So i gave it constant power to the fuel pump and it runs strong. My question is is this right and does it need constant priming?
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Joined: Feb 2007
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From: Oregon
Once the bike is running the fuel pump runs consistently.
"Since a fuel pump it draws a lot of current (more than we'd like to see going through the ECU itself), it is powered with +12-l4v from the battery via a relay, which is switched by the ECU. Many systems will cycle the fuel pump for several seconds at key-on, then power down the pump until after the bike's engine is turned over. This ensures proper system pressure during starting." (Motorcycle Fuel Injection Handbook)
"Since a fuel pump it draws a lot of current (more than we'd like to see going through the ECU itself), it is powered with +12-l4v from the battery via a relay, which is switched by the ECU. Many systems will cycle the fuel pump for several seconds at key-on, then power down the pump until after the bike's engine is turned over. This ensures proper system pressure during starting." (Motorcycle Fuel Injection Handbook)
Senior Member
Joined: Apr 2008
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From: Northern Michigan
Are you getting power to the relay? Are you getting power to the source on the relay when you first turn on your key?
I would take a volt meter and check the power to the two power supply points for the relay. Remove the relay and test those spots. Im not sure which one are which, but you should have one constant power, and one that will cycle when the key is first turned on. If you have both of these present, I would suspect your relay is bad. turn you key on and check for the constant, then, start checking the others. Put your probe on one, cycle the iginition and see if you get power. Then do this to all of the other points. The main supply should be around 12 volts. But the other is only a signal and is minimal. you will need a volt meter that reads small voltages. It will probably be around .3 volts or so.
I would doubt your ecu is bad. It possible, but the most likley problem is the relay, the fuse, or your BAS. Im not sure if the BAS on that bike shuts power off to just the fuel pump, or the fuel pump and the spark. A lot of bikes its only the fuel pump, but on some its both.
I would take a volt meter and check the power to the two power supply points for the relay. Remove the relay and test those spots. Im not sure which one are which, but you should have one constant power, and one that will cycle when the key is first turned on. If you have both of these present, I would suspect your relay is bad. turn you key on and check for the constant, then, start checking the others. Put your probe on one, cycle the iginition and see if you get power. Then do this to all of the other points. The main supply should be around 12 volts. But the other is only a signal and is minimal. you will need a volt meter that reads small voltages. It will probably be around .3 volts or so.
I would doubt your ecu is bad. It possible, but the most likley problem is the relay, the fuse, or your BAS. Im not sure if the BAS on that bike shuts power off to just the fuel pump, or the fuel pump and the spark. A lot of bikes its only the fuel pump, but on some its both.
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