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SOLVED - HELP! No power at the fuel pump plug - No signal from the ECU pin4 to trigger the relay

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FZ1_Dan

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Apr 21, 2025
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Good morning all.
I just joined this forum as I'm looking for help!

I really hope there is someone out there who could point me in the right direction to get my bike on the road.

The bike died on me while riding. Straight away I knew it was something to do with the fuel pump as I couldn't hear it priming anymore.

After spending Easter in the garage, I found out that I'm not getting a signal (NEGATIVE/0V) from the ECU pin4 to the relay. The relay unit has to coils inside. I can hear it clicking when flipping the kill switch to the Run position, but that's the cut-off switch side of that relay. On the fuel pump relay side, I'm getting positive as soon as I flip the switch, but still the relay doesn't work. I put a multimeter between the battery's positive and the relay coil pin where the Neg should be and saw zero V.
I tested the relay outside the bike, following the manual it works.
I tested wires between the ECU and the relay, between the relay and the pump - all good.

So the problem is no signal from the ECU pin4 to the relay (blue/yellow wire). I'm trying to add an image of the wiring, but I can't for some reason.

Fried ECU?
The immobiliser?

Any ideas?
Im gutted.

Please help.


Best
Daniel
 
Have you measured the voltage at the fuel pump connector with the ignition on and the run switch flipped on? This voltage is only there for a couple of seconds. If you do have voltage for a couple of seconds then the fuel pump has failed which has happened to me.
 
jwarden said:
Have you measured the voltage at the fuel pump connector with the ignition on and the run switch flipped on? This voltage is only there for a couple of seconds. If you do have voltage for a couple of seconds then the fuel pump has failed which has happened to me.
Click to expand...
Hi. I went to the garage yesterday after posting here, and I managed to get it working. YES, YOU ARE RIGHT! The voltage there is only for 2 secs or so, and then later when you're about to crank the engine - I DIDN'T KNOW, expecting voltage to be there all the time. When my bike died, I replaced the fuel pump straight away, but because I wasn't getting any voltage there, I didn't even put the tank back to test. So I wasted my Easter weekend trying to repair it, but it was the pump! As I started putting things back together, I pushed the button, and then I heard the pump working! I was like WHAT! ... Mate. If I posted here on Saturday and got your reply, that would save me 2 days off digging and investigating. So this is now solved; it was the fuel pump. What a weekend.
 
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