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11254 Views 28 Replies 8 Participants Last post by  desmillie6969
Hello everyone,
My name is Vladimir and yesterday I bought my first Fireblade :clap::thumb:, 2001 CBR929RR with 22k miles, pretty clean except for a dent in the gas tank and some minor scratches. Here is the issue: when I turn it on there is a click and the fuel pump starts priming however it doesn't stop running after couple of seconds but continues to run after the priming is finished! As the pump continues to run I hit the start button and the engine starts and idles fine. Also a red light flashes on the dash display. I asked the previous owner about this and he says he never bothered to look into it because the bike always ran fine. Now my question is: which component in the system tells the pump to stop priming (until the engine is turned on)? Is it the fuel pressure regulator, fuel stop relay or something else? :idunno: Any help would be very much appreciated....:rotfl:Thank you


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No but I can go get one at work. :rolleyes: I guess thats my next step. So yours was the ECU?
Yeah. Basically the relay is a switch that turns the fuel pump on or off. The relay allows you to switch something with a large flow of current (fuel pump) with something that has a small tolerance to current (the ecu)
Therefore the small switch part of the relay has 12V in from the battery. The other side then goes to the ecu. If the ecu wants the fuel to go on it makes that cable to earth and allows a flow of current to go and therefore turns on the switch (relay). This then allows 12V to be sent up to the fuel pump.
Therefore the relay is either stuck on and the ecu isn't telling it to go on. Or the ecu is bust and is always saying to go on.
Or someone has wired a direct 12V feed to the fuel pump (happened to me!!! because the ecu was broken)
Or the wire that goes back to the ecu from the relay is shorting to earth.

Good luck!
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Does your buddy have a CBR929 if so you could try his ECU in your bike.
Already swapped that. I made a patch cable and used every sensor on his bike while turning on mine. which eliminated I feel everything. :mad:
Although I had a new fuel pressure regulator installed it did sit on the shelf a while before use. I have done the vacuum line pull off test and no leak. Makes me wonder if a FPR can still be bad even if it doesn't leak. :idunno:
Update from me on this thread for others to read for help one day:
As I was at my wits end:mad:, I ordered and replaced the FPR just because. That didn't do anything but it has sit long enough that now I have peace of mind it is new as it seems to be the majority of peoples problems at one time or another. I decided to start peeling electrical tape in search of previous owner shenanigans:eyebrows:. I found a spot behind the fuel pump relay where someone had spliced 2 wires together for the pump to run continuously. I separated the wires as they should be and the pump wouldn't run at all. I then popped in my buddies working ECU and :eek: the pump ran as it should. It primes for 4 or so seconds and stops. So that issue is solved!:thumb:

Now it just cranks (turns over) but will not actually start. I will not continue my issues on this thread as it is not relevant but will be searching elsewhere. Thanks to you for your help up to this point!:smilebig:
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heads up, it could also be possible, I THINK, for the zeener diode in the ignition to go bad over time, and cause some voltage fluctuations and funk with the fuel pump. people always seem to forget about the diode in the ignition. bought a couple 929/954s that people didn't know how to fix. plugged a good ignition into them, fired right up. Had a diode go bad on a personal bike once, no idea why. never seen it cause THIS issue, but I imagine as time goes on they will cause issues.
I just started having issues with my ride as well. on the display the red light is on and the [FI] indicator is on, the bike sounds a little rough when i ride, before i arrived home from work i stopped for fuel, when i went to start it i heard what i thought was the fuel pump priming, but it sounded like a "leaf stuck in a fan" my first thought is that the fuel pump is going out. does this wound about right to anyone?
I got the schematic diagram for the bikes wiring and then traced it all to see what wasn't working
Has anyone figured out anything on this problem? My bike is doing the exact thing and it's really driving me crazy, I love my 929 but something has got to give.
I got the schematic diagram for the bikes wiring and then traced it all to see what wasn't working
Could you send me a copy
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