Suspecting this could be an ECM fault.
Is there a way I can be 100% sure before sourcing a ECM..

 

The relay has been removed and a jumper put in it's place? You don't need an ECM, you need to put a relay on that plug. Their is an inductor inside the relay. If the PO added wires to that circuit to run aftermarket lights I would remove them.

 

 

Unfortunately I tried just using the high beam relay - that I knew was good with no luck… the bike would
Not prime.
The jumper is from the black and white straight to the brown/fuel pump so bypassing the brown and black cable. So I had thought is there an earthing issue with the ECM - or is the ecm not providing enough power to the fuel cut off relay..
there’s no additional wiring that I can see just that the oem rear light and turn signals have been changed.

 

The head light relay swap was going to be my next suggestion, but you can also try swapping it with the bank angle sensor as that will cut off the fuel too. Also, check that your power commander is correctly grounded to the battery.

 

the ecu controls the fuel pump by switching the brown/black at the fuel pump relay to ground


put a multimeter on continuity between the brown/black at the relay connector to the negative terminal of the battery, and cycle the kill switch. if you don't get a tone, you know where to look. test again right at the ECU, test that all the grounds to the ECU are good. etc etc.

 

The head light relay swap was going to be my next suggestion, but you can also try swapping it with the bank angle sensor as that will cut off the fuel too. Also, check that your power commander is correctly grounded to the battery.

the ecu controls the fuel pump by switching the brown/black at the fuel pump relay to ground


put a multimeter on continuity between the brown/black at the relay connector to the negative terminal of the battery, and cycle the kill switch. if you don't get a tone, you know where to look. test again right at the ECU, test that all the grounds to the ECU are good. etc etc.

hmm yep there is nothing at the replay or the A8 connector at the ECM. So no direct power is going to the relay right?

 

ok scratch that - when the relay is plugged in..
The back/brown wire from A8 - is delivering 10 volts . So is that not enough to power the relay..
Sorry I’m confused…
So you think it could be an ecm grounding issue ? Or the actually ecm it’s self

 

no i'm not sure you understand


the black/white wires are 12v positive. they come from the bank angle relay (the 30amp fuse off the battery feeds the bank angle sensor relay, from there it becomes a black/white that feeds the ENTIRE EFI SYSTEM



so you are taking 12v positive to all the devices, and then the ECU switches the negative

obviously your black/white is energized, because the pump works when you jumper black/white to brown

the ecu is switching the back side of the coil of the relay to ground. if you jump brown/black to battery negative, the pump will run with the relay installed


your job is to determine whether the ECU is trying to ground that wire or not. if it isn't, the solid state device in the ECU that is responsible for switching this circuit may be failed. but before you decide that, you have to make sure that all the wiring on the front and back side of that circuit is in tact.

 

thank your that reply..
Really appreciate it.. hmmm ok..
not sure where to start looking.. do you have any tips of where to start?
again I really appreciate you explaining has made way more sense

 

the black brown doesn't deliver anything. it's a ground

connect it to battery negative, does the relay turn on?


i'm sorry man but if you don't understand how i'm explaining this i'm not sure i can say it any more clearly

 

Apologies yep you make perfect sense! Really appreciate it!
And yes the pump primes if if connect it to ‘-‘
So like you said now I have to check the circuit…so with the relay plugged in it clicks but no priming - if I jump the black/white to the brown it powers the fuel pump. so it’s possible a grounding issue somewhere in the circuit or the ecm hard drive like you said.

 

correct. you might need to find a friend with some test equipment to help you. but it could absolutely be an ECM issue.

 

Just one more question after checking the grounds I came across this sub…
So I’m not getting power at the B18 pin - but A10 A11 do ground.
I see the B18 pin gets its power from the starter relay ?? Is that a possible fault ?

 

b18 has nothing to do with the starter relay. it has to do with the neutral sensing circuit. if the bike is in neutral you should see 12v. if it's not then you won't. this has nothing to do with your pump not priming


the only pin you need to worry about is a8 where the fuel pump relay is controlled, which i told you about previously



another thing that will stop the pump priming is faults in the fuel system (ie fuel injectors etc). if there's a code associated with those circuits the bike won't run the pump (for obvious reasons)


so you should be seeing if you get action on a8, if not, check for codes, if no codes, try a known good ecu.

 

Ok so if I’m not getting power at the b18 that wouldn’t affect the bike priming?
Would that be a starter relay issue ?

but yes A8 is fine. All ecu grounds are fine that I have checked…
Just is saw that other sub that says if b18 isn’t getting power then there is a ECU power issue?

 

it has nothing to do with the starter relay, it has nothing to do with pin b18 i don't know where you're coming up with this stuff


how do you know a8 is fine? does it switch to ground when you cycle the kill switch? have you verified this? if it does, then it will control the fuel pump relay, but you claim it isn't

 

it has nothing to do with the starter relay, it has nothing to do with pin b18 i don't know where you're coming up with this stuff


how do you know a8 is fine? does it switch to ground when you cycle the kill switch? have you verified this? if it does, then it will control the fuel pump relay, but you claim it isn't

it has nothing to do with the starter relay, it has nothing to do with pin b18 i don't know where you're coming up with this stuff


how do you know a8 is fine? does it switch to ground when you cycle the kill switch? have you verified this? if it does, then it will control the fuel pump relay, but you claim it isn't

ok Wibby thank you. But no a8 is not going to ground apologies. I just thought if power is getting to the relay - then it would just stay priming - the A8 grounding would stop the pump.
The pump clicks when I switch the kill switch from on to off though.

 

Thank you Wibbly really appreciate your help… I realise on a different feed you’ve helped out someone similar…
When I ground the black/brown then the pump primes - it’s a weak but it primes..
Would that point to a ECM fault then as like you said it actuates the fuel pump.

 

the ecu grounds the black/brown like i said like 10 posts ago. if it's not doing that it could be because it doesn't want to (fuel system fault) or it's got a bad connection somewhere, or the internal circuitry is failed

the click you're hearing when you toggle the kill switch is the bank angle sensor relay, not the fuel pump.



i can't explain this any clearer man. i've been repeating myself for too many posts now. i think you have all the info you need to get an adequate diagnostic. good luck.

 

.

 

It sounds like you're dealing with some wiring issues that could definitely be affecting the fuel priming on your bike. If the previous owner bypassed the fuel stop relay, it’s likely they were trying to address a different problem, but it could have led to this priming issue.