2008 No Start... Electrical Gurus Please Chime In

mcantar

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I'm not sure what's going on here. Fuel pump isn't priming (Bosch 044), starter isn't kicking over when I press the button. Ignition on, killswitch on, kickstand/neutral/clutch safeties seem to be functional, TOS disabled in ECU but plugged in and right side up just in case (after trying it without). I have ~12.5v across the battery, full voltage to and from ignition, full voltage at the starter button. No power at the Y/r fuel pump wire. Interesting note, I have full voltage coming from the starter button both when depressed and when not, not sure if that's normal. Fuses look good.
Electrical stuff is my kryptonite.
Any thoughts?

dadofthree

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I would say interlocks but you said you had that covered. You have fuses to check and there's a fuel pump relay. I hear ya on that voltage check, but have you had the battery load tested ? More than likely not the issue, but I asked. If you've done any work to the bike or added anything just prior to this start there.

RedBusarider

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Maybe it's just a different way to word something - but I think your Kill-switch should be OFF.

When you turn the key on - does the temp gauge go to full hot? If so, the Emergency switch is on.

Did this no-start issue just pop up? Was fine the last time you started it?

Kevin Jones

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It sounds like the clutch or kickstand switch. Don't ask me why. Gut but I could be wrong. We need a wiring diagram. Can someone post a wiring diagram for a k8? I have the service manual on digits but its hard as hell to look at.

Kevin Jones

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Shits n giggles, take the leads off the clutch switch and jumper wire across. Bike in neutral, key on, emer switch on. See if FP primes.

mcantar

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Do3: All the fuses are good. Haven't checked the relays. Battery has not been load tested, but functioned properly when I took it out of the bike.

Red: It's set to run... whether you want to call it on or off. I always use it to kill the bike anyway, on all my bikes, so it's something I always interact with and it's must definitely in the run position.
I plugged the OEM gauges in today (I have a Koso RX1N mounted but not connected, and I haven't touched the harness yet so the harness is still as it left the factory) to see if I could get an FI code from it, and nothing happened when I turned the key... no needle sweep, no lights, nothing.
It was a perfectly running bike when I started working on it in November. Since then it's gotten some serious mechanical and aesthetic modification, but the electrical system is untouched. I numbered all the connections I unplugged on both sides, everything's plugged in where it should be with the exception of the lights (head, tail, maker), and the grounds are all there and were actually never touched.

Kevin: I didn't mess with the kickstand or switch at all... the handlebar controls were completely removed from the bike, but the wiring was never tugged on and the connections seem tight. I'll try jumping them, but I don't think either of those are the culprit as the gauges aren't even turning on.

Here's a PDF wiring diagram:
https://www.google.com/url?sa=t&sou...R1TVwOBjlTzzOoInQ&sig2=1mLgAj-ytrvkdE5d3oNs-g

So, strange thing. My tuner and I were checking through some connections with a test light today. Had the wire connected to the negative battery lead, looking for anything that should have power and doesn't. When he touched the probe to the hot wire going to the ECU (O/w or O/y I think it was), thereby providing ground to it, the fuel pump kicked on. This is at that white connector with the blockoff plug at the back of the harness. No response at the gauges though.

Kevin Jones

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Does your tuner have a spare ecu you can pop in for a minute? Most folks would say that when an ecu fails, it completely dies. I had one fail and that was not the case. I lost the 5v signal coming from it completely. I bought a used ecu, flashed it and all was well. From that point on, I considered and still want to have a spare ecu laying around for testing. I will tell you that I was so convinced it wasn't the ecu that I spent probably 20 hours testing and baffled at the results.

mcantar

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I think that's our next step Kevin. I'm about to head over to his shop (brought the bike there yesterday), hopefully I'll have a positive update for you guys later.

mcantar

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vhyfxm.jpg


Well, my tuner was messing around with it last night after I left and found the issue. Something about the harness ground, I'm not 100% sure but it functions now. Well, the OEM gauges (that are hanging off the side of the bike) turn on and the pump primes, anyway. Have to set the cam chain tension and base fuel pressure before starting it up and tuning it.
Thanks for your help, guys.
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