RBstman1 here can you tell me how much resistance there should be on the fuel pump assembly feed through to the fuel pump motor. when i first turn on the bike the 12v is at the electrical connection brown wire and ground for 1-2 sec. for priming but the pump won't turn on. 12v direct to the pump motor activates the pump but through the feed thru wire to the pump motor will not let voltage thru. to the connecting wire to the pump motor is this feed thru connection bad if it has 12 to15K ohm on it? Please help
2006 st1300 fuel system problem
- Thread starter RBstman1
- Start date
Andrew Shadow
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Have a look at the below thread.
ST1300 - Fuel Pump Circuit - Fault Diagnosis
ST1300 - Fuel Pump Circuit - Fault Diagnosis
- Joined
- Mar 18, 2006
- Messages
- 2,836
- Age
- 70
- Location
- Ilkley, W Yorkshire, UK
- Bike
- 2013 ST1300 A9
- 2024 Miles
- 000679
- STOC #
- 2570
The pump turns if 12v is applied to it directly?
Power is reaching the brown wire at the connector for the fuel pump fo 2 seconds ?
I've just copied this diagram from my article here: Link. The contents of the pdf explains each of the 3 separate circuits.
The fact that the motor turns when it is powered directly suggests that it should also turn when powered by the 'system'.
The power on the brown lead turning off after 2 seconds suggests that the 'switch' in the ECU is working correctly.
Those two things are confusing. It should work, given that information. So I need to ask some questions to be sure that you are actually seeing what you describe.
Where did you get the power from to make the pump work ?
Where did you apply the +ve and -ve leads ? ie where did you apply the +12v and where did you apply the negative battery feed.
Can you confirm that you tested the 12v at the brown lead and not at the brown / black lead . You might need to go back and do this again because you cannot always see the black stripe on the brown/black lead.
I am suspecting a dodgy earth lead or a bad battery at the moment, but I need more precise information about your tests to be able to help.
Power is reaching the brown wire at the connector for the fuel pump fo 2 seconds ?
I've just copied this diagram from my article here: Link. The contents of the pdf explains each of the 3 separate circuits.
The fact that the motor turns when it is powered directly suggests that it should also turn when powered by the 'system'.
The power on the brown lead turning off after 2 seconds suggests that the 'switch' in the ECU is working correctly.
(I doubt that it is a switch / relay, but an electronic device that acts like a switch in this case.)
Those two things are confusing. It should work, given that information. So I need to ask some questions to be sure that you are actually seeing what you describe.
Where did you get the power from to make the pump work ?
Where did you apply the +ve and -ve leads ? ie where did you apply the +12v and where did you apply the negative battery feed.
Can you confirm that you tested the 12v at the brown lead and not at the brown / black lead . You might need to go back and do this again because you cannot always see the black stripe on the brown/black lead.
I am suspecting a dodgy earth lead or a bad battery at the moment, but I need more precise information about your tests to be able to help.
Last edited:
Thanks 
i tested the 12v directly from a d/c power supply, directly to pump contacts, and the battery on the bike; grounded the green wire to battery grd brown wire confirmed. not the brn/blk. and 12v + from batery to the brown wire on the inside of the feed thru and at motor + .but when i try and power the pump thru the connection cable at the connector i get no pump activation. thanks for the response. do you know if the glued on feed thru has resistor imbedded in the connection feed thruThe pump turns if 12v is applied to it directly?
Power is reaching the brown wire at the connector for the fuel pump fo 2 seconds ?
I've just copied this diagram from my article here: Link. The contents of the pdf explains each of the 3 separate circuits.
The fact that the motor turns when it is powered directly suggests that it should also turn when powered by the 'system'.
The power on the brown lead turning off after 2 seconds suggests that the 'switch' in the ECU is working correctly.
(I doubt that it is a switch / relay, but an electronic device that acts like a switch in this case.)
Those two things are confusing. It should work, given that information. So I need to ask some questions to be sure that you are actually seeing what you describe.
Where did you get the power from to make the pump work ?
Where did you apply the +ve and -ve leads ? ie where did you apply the +12v and where did you apply the negative battery feed.
Can you confirm that you tested the 12v at the brown lead and not at the brown / black lead . You might need to go back and do this again because you cannot always see the black stripe on the brown/black lead.
I am suspecting a dodgy earth lead or a bad battery at the moment, but I need more precise information about your tests to be able to help.
There is no reason for a resistor in the supply wire to the fuel pump. The color enlarged wiring diagram I have for 06 1300's* shows no resistor.
If I understand you correctly, you applied 12v. to the fuel pump at the pump and above it on the underside of the cover, and it ran, but when you apply the same 12v (i mean both + and - ) to the outside with bike harness disconnected, you do not get a running pump? if this is the case, that feed through connection is broken. You could easily determine this with a continuity tester or a DVM.
*Downloaded from this website
If I understand you correctly, you applied 12v. to the fuel pump at the pump and above it on the underside of the cover, and it ran, but when you apply the same 12v (i mean both + and - ) to the outside with bike harness disconnected, you do not get a running pump? if this is the case, that feed through connection is broken. You could easily determine this with a continuity tester or a DVM.
*Downloaded from this website
- Joined
- Mar 18, 2006
- Messages
- 2,836
- Age
- 70
- Location
- Ilkley, W Yorkshire, UK
- Bike
- 2013 ST1300 A9
- 2024 Miles
- 000679
- STOC #
- 2570
That clinches it doesn't it ?q
Motor not working if powered at the end of the cable
Motor is working when powered closer to the motor.
From the same power source.
There has to be a fault between those two points.
As far as I can see from the info given, there is nothing failing in that circuit diagram. Power is reaching the connector, the Ecu is turning the circuit on and off at the right time.
Final test - wire the motor to the connector using different cable. make sure it turns on for 2 secs, then turns off.
Motor not working if powered at the end of the cable
Motor is working when powered closer to the motor.
From the same power source.
There has to be a fault between those two points.
As far as I can see from the info given, there is nothing failing in that circuit diagram. Power is reaching the connector, the Ecu is turning the circuit on and off at the right time.
Final test - wire the motor to the connector using different cable. make sure it turns on for 2 secs, then turns off.