Chasing electrical issue (fuel pump/ECU)

TallPaul

Joined
Nov 20, 2023
Messages
3
Age
34
Location
Florida
ST-Owner Group Members,

Just want to start out by thanking all of those that have provided help already and sent over resources on how to track down this fuel pump / electrical issue I am dealing with on my '09 ST1300PA.

Using the fuel pump troubleshooter guide, I was able to figure out the different relays and which components do/don't have power.

Specifically the brown 12v from the fuel pump is not getting power while the bank relay sensor is getting all proper power/grounds.

Following the answer sheet I had been provided with, it states that my issue is being caused by a bad switch somewhere else on the bike, kickstand or clutch, neutral safety switch etc. I have been checking these but finally determined that the issue is likely the ECM itself.

I see how expensive these things are online and am ready to throw in the towel and pick up a new ST altogether.

The trouble that I am having is the fuel pump is not priming. If I jump the ground cable on the relay, it does get ground and you can hear it prime when I turn the on/off switch.

Is there anyway I can bypass the ECM or any other fixes for this besides replacing the ECM itself? I understand that the ground connector is within the circuitry of the ECM and it is sealed and can't be fixed.

Any help is very much appreciated.
 

Attachments

  • 20260219_231532.jpg
    20260219_231532.jpg
    82.8 KB · Views: 10
  • 20260219_231631.jpg
    20260219_231631.jpg
    103.9 KB · Views: 9
  • 20260219_231650.jpg
    20260219_231650.jpg
    160.5 KB · Views: 9
Remove your air cleaner assembly and check for damaged wires under the throttle bodies, especially the wires to the fuel injectors. Any defect detected with the fuel injectors causes the ECM to disable the fuel pump until the defect is no longer detected. Mice like to eat these wires.
 
Andrew Shadow said:
Remove your air cleaner assembly and check for damaged wires under the throttle bodies, especially the wires to the fuel injectors. Any defect detected with the fuel injectors causes the ECM to disable the fuel pump until the defect is no longer detected. Mice like to eat these wires.
Click to expand...
Have the airbox off and inspected the wires. Made sure everything was plugged in but I guess I should do a continuity test on those as well. Thank you.
 
Just for grins check the condition of the green wire going into and out of the white 24 pin connector located above the left valve cover. A toasted or crispy ground (green) wire is known to cause random electrical problems. When my 2005 ST was exhibiting strange electrical issues including shutting down the fuel pump I eventually jumped the green leading out of the connector to good ground and the fuel pump spun up. Running again!
 
dduelin said:
Just for grins check the condition of the green wire going into and out of the white 24 pin connector located above the left valve cover. A toasted or crispy ground (green) wire is known to cause random electrical problems. When my 2005 ST was exhibiting strange electrical issues including shutting down the fuel pump I eventually jumped the green leading out of the connector to good ground and the fuel pump spun up. Running again!
Click to expand...
Checked and confirmed continuity. Still no luck getting this figured out unfortunately. Running out of patience and free time to get it fixed. Thinking about just getting it back to the shop at the moment.
 
If you are going to check grounds, there is a large, 23 pin connector behind the headlight (iirc, right side) that often becomes a problem.

You mentioned getting it back to the shop. Few of us have had good luck with mechanics working on these bikes. The bikes are reliable, the mechanics see few of them, and there are time and money constraints under which they work. If you are taking your bike to a repair shop, I hope you have a better experience than most of us.
 
Last edited:
My bike quit and it had no power on bk/w wire of fuel relay.ran a jumper wire to bank angle relay bk/w are you sure yours does? You say yours is missing the ground control of fuel relay.check that circuit for open between ecm- relay. I Put 12,500 mi since repair working fine.it has a burnt terminal in power splice connector under throttle body ,may one day deal with it ,then cut jumper or not
 
If you add ground jumper at relay terminal for coil of relay it runs pump? You must have open circuit between relay terminal and ECM terminal from what I Understand,or ECM problem.You could rig a led test light close to ECM terminal and look for ground signal there? No Internet at home to spend much time thinking, checking
 
You must log in or register to reply here.
Back
Top Bottom