Posts
28
Joined
12/29/2017
Location
Broadway, NC, USA
Hey guys.
2023 YZ450F w/ 50hrs
Bike stalled in a corner. Thought I was out of gas so I opened gas cap and after trying a couple more times it lit up w/o issue. Figured it was a venting problem...
After about an hour of trouble-free riding the bike cut out under throttle and hasn't started since.
- Fuel pump doesn't prime (I thought it was a bad fuel pump, so I stupidly bought one that night w/o diagnosing first bc I wanted to ride this weekend. New one won't prime either
- My CCU is no longer popping up
- Bike cranks but no spark
- I've unplugged/checked/cleaned every single connector and fuses.
- Handlebar orange light fast blinks 6 times (I looked at service manual and it just said "electrical problem"
With my CCU going out the same time as my fuel pump and not having spark I dread that my ECU went bad - was hoping for a sanity check/other t-shoot steps before I eat the 500 dollars to replace it.
You have no spark and no fuel? Seems like it's usually only 1 of those problems at a time.
Yep. No spark. No fuel. No CCU. Only thing that works is the starter (fully charged battery also)
I’ve stripped the whole wiring harness looking for corrosion or breaks. It’s super clean. I’m not the best electrical guru but I’m still perusing the service manual doing all the multimeter checks, but I may be testing incorrectly.
Disconnect ECU and reconnect see if anything changes Could be wire harness
Just thinking out loud:
I'd probably disconnect the battery for a couple minutes and see if that resets anything.
The CCU is the input device for adjusting Fuel and Ignition.
The bike will run normally with CCU disconnected, so that rules out the CCU as the cause.
Having no Fuel, no Ignition, and no CCU recognized all at the same time, that indicates to me it's the mechanism used for combining the fuel and ignition inputs (which is adjusted by the CCU).
Does the CCU wire directly to the ECU?
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Did you pull the relays and test those with a multimeter as well?
Borrowed a known good ECU and still same symptoms.
Starter relay tested good.
I did notice that my fuel pump turns on for just a split second when I hit the starter.
I've read that a bad rectifier can cause all my issues. I have a cheap multimeter and I tried the diode testing function but I'm not getting any results from it. I hate throwing parts at it but I'm just gonna order a rectifier and if it's not that I'll just pay a restocking fee.
Update: it was the rectifier AND the kill switch. (Yes I unplugged the kill switch before I swapped anything).
Once I replaced the rectifier I was able to get into the CCU but still no fuel prime. Then I unplugged the kill switch/map button and she lit right up.
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