Won't prime but works if I jumper the fuel cut off relay - Honda Motorcycles - FireBlades.org
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post #1 of 10 Old 04-15-2015, 3:07 PM Thread Starter
 
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Won't prime but works if I jumper the fuel cut off relay

Right well I've had the bike (cbr929) for a few months now and it's been running good.

There was one issue I noticed and that was the bike doesn't do the usual prime fuel. The fuel pump is just always running.
It turns out the fuel cut off relay has been jumpered.


If you fit a relay it just doesn't prime and the fuel pump is not running.
The engine stop relay is working as well as the lean angle sensor. As I've just replaced both with the lean angle not mounted. When tilted it activates the engine stop relay.

So does anyone have any ideas why it won't work unless it's been jumpered?
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post #2 of 10 Old 04-15-2015, 3:26 PM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

If you look at the wiring diagram both black cables going into the fuel cut off relay have 11v when the ignition is switched on. When I change the jumper from brown (to fuel pump) to either black they both power the fuel pump and the bike runs.
That leaves the other brown that goes to the ecu. So effectively the logic that the ecu uses to complete that circuit is not happening. Any ideas?

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post #3 of 10 Old 04-15-2015, 3:36 PM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Could it be the diode in the ignition?
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post #4 of 10 Old 04-16-2015, 5:42 AM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Ordered this (BZX79C 3V9 0.13A Zener Diode | Maplin) and my mate in work has lent me his torx with the pin set.
Wish me luck!
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post #5 of 10 Old 04-17-2015, 6:59 AM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Fail!
There was no existing diode in the ignition ....
Even installing a new diode it still doesn't work.
TBC!
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post #6 of 10 Old 04-17-2015, 7:30 AM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

So doing some digging the UK bikes don't have a pink wire from the ignition. What I thought was the pink wire was in fact the power to the fan.
Anyone from the UK had this issue?
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post #7 of 10 Old 04-18-2015, 10:12 AM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Thanks me!
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post #8 of 10 Old 06-23-2015, 2:42 PM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Right folks who will be reading this in future hoping for the answer.. I now hopefully have mine! After reading a similar post on here it was concluded it was the ECU. I therefore sent mine off to be checked by carmo electronics in the netherlands. Today they have got back to say my ecu was indeed defect and that they have repaired it! Happy days!!!
They also said it was prob the fuel pump relay that caused the fault to the ecu.
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post #9 of 10 Old 06-23-2015, 5:25 PM
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Re: Won't prime but works if I jumper the fuel cut off relay

I guess I'm late to your par-tay, Ace. Glad to hear you got it squared-away. ECU is usually one of the last things to go, but when wires get "jumped" and relays get bypassed, that's a surefire way to "fry" them. Sucks that you found out the hard way, but good to hear things are as they should be now

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post #10 of 10 Old 07-02-2015, 4:31 AM Thread Starter
 
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Re: Won't prime but works if I jumper the fuel cut off relay

Well I bought the bike like that so wasn't me
Got the ecu back and right enough it now primes as it should.
Although from my other thread it won't run with the side stand down in neutral.
Still runs great though when it's up. Never ending story
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