Fuel pump not working, not sure what to try next. 06 GSXR 750

1936 Views 7 Replies 3 Participants Last post by MBGixxer750, Jun 10, 2021

MBGixxer750

Discussion Starter · Jun 3, 2021

I was riding my 06 GSXR 750 a few weeks ago when my bike completely shut off, engine and dashboard. I pulled over to the side of the road. I assumed my battery was dead, so I ignorantly used a police tahoe to jump the bike while the tahoe was running. My bike started tho for about 3 minutes I left it to idle when it cut off again. This is when I opened the seat and see that the battery has expanded and was leaking.

So I replaced the battery and the bike started again. I got about 5 min down the road when everything cut off again. Now I have towed the bike home. I checked the rectifier and stator with the resistance tests that you can do with the bike off. It showed that the rectifier was bad so I replaced the rectifier and relocated it to the airbox.

I put the bike back together and turned it on. My low beam light was blown. Then I turned the kill switch to run position and it instantly popped my ignition fuse. I went through the bike and found the indicator/fuel pump relay located in the tail of the bike was making a funny noise, my right side indicator lights also blew out of nowhere while sitting in the garage. So I replaced that and now the ignition fuse is no longer blowing and my indicators are good. So now the bike is cranking, but the fuel pump won't turn on so the engine won't start.

I checked the relay at the front right of the airbox as well. Using a multimeter I checked to see if the yellow/red wire showed any voltage when I put the kill switch in the run position, and it doesn't show anything. I also cant feel the relay itself click or vibrate when I move the kill switch to run position. I also checked the power wire going to the fuel pump itself, also no power.

Lastly, on my dashboard, I am constantly showing chec. I put it into dealer mode, it still says chec. Then in the gear position window, I just have a "-" now, I think it used to say "N" when the bike was off and in neutral.

Has anyone had this happen, or something similar, what can I check next? I've also looked at all the relays and checked for shorts/exposed wires, everything looks good. CAN ANYONE HELP?? I am missing riding season!

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MBGixxer750

Discussion Starter · #4 · Jun 5, 2021

BillV said:
This is based on a K6 1000 but it ought to be very similar.

You're right about "ignorantly used a police tahoe to jump the bike while the tahoe was running". Mistakes can be made under the stress of a breakdown and that could be the source of your current problems.

The interlock/turn signal relay is next to the fuses and is different from the fuel pump relay. There ought to be a O/W lead at the fuel pump relay. It should be battery voltage with the ignition and engine stop switches on (it also provides power to the ECM). There should also be a R/Bl lead. It should always be battery voltage. There should be a Y/B from the relay to the ECM. It should be near to battery voltage when the pump is not running and near zero when it is running, including priming. Finally there's a Y/R lead to the pump. It should be zero when the pump is not running and battery voltage when it's running. All voltage checks at the fuel pump relay should be made with the relay connected. The ECM controls the relay via the Y/B lead. You should be able to monitor it when the bike is turned on and see its state change. The ECM is suspect if it has power and is not controlling the fuel pump relay (it should have power if the bike cranks). The only thing that would prevent that is the tip-over switch and I assume that it hasn't been fiddled with.

CHEC means that the cluster isn't receiving data from the ECM. The "-" is likely related to that.

Okay, so the main check I need to do is with the Y/B lead on the fuel pump relay, if it does NOT have power, then the ECU is suspect correct? Because the bike cranks, the ECU does have power, so if its not giving power to the pump relay its most likely bad.

Thanks for the info, I will try this tommorow.

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MBGixxer750

Discussion Starter · #6 · Jun 6, 2021

BillV said:
" if it does NOT have power, then the ECU is suspect correct?"
That's a misstatement. Y/B gets power from the O/W. It's voltage will be 12 V or a volt or so depending on what the ECM is doing. It will always be high if the ECM isn't working. If the ECM is working, it will be high or low depending on where you are in the prime/run procedure.

I just completed all the checks. The Y/B lead is 0 when the key is on, and kill switch is in the kill position. Once I turn the kill switch to run, then I get 12V, and it remains at 12V. This is indicating bad ECU correct?

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MBGixxer750

Discussion Starter · #7 · Jun 6, 2021

MBGixxer750 said:
I just completed all the checks. The Y/B lead is 0 when the key is on, and kill switch is in the kill position. Once I turn the kill switch to run, then I get 12V, and it remains at 12V. This is indicating bad ECU correct?

All the other leads were as you said they would be.

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MBGixxer750

Discussion Starter · #8 · Jun 10, 2021

I replaced the ECU, fuel pump is working now, and bike starts!

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