Electrical Gremlin Strikes Again

[TURBO200R4]

Battery is sitting at 12.68 volts, outside of the bike. Attached jumper cables to the battery and the starter, the starter spins nicely. I think it's nicely, all I can say for sure is that it does spin. I will start checking the circuits looking for a lower voltage. Should I still be looking for less than 10 volts?

yes
now that we know we have enough volts to crank over we start looking for why it will not crank.
once we confirm that we have more or less than 10 volts at those fuses while putting a load on it (pushing the starter button.) actually may or may not be putting a load on it.
i would venture to say if we have 12 volts on all the fuses that probably we have good ign and the fuse terminals r ok. then we will be ready for next step

 

[Tripps]

Battery is sitting at 12.68 volts, outside of the bike. Attached jumper cables to the battery and the starter, the starter spins nicely. I think it's nicely, all I can say for sure is that it does spin. I will start checking the circuits looking for a lower voltage. Should I still be looking for less than 10 volts?

Less than 12.5 is probably trouble.

yes
now that we know we have enough volts to crank over we start looking for why it will not crank.
once we confirm that we have more or less than 10 volts at those fuses while putting a load on it (pushing the starter button.) actually may or may not be putting a load on it.
i would venture to say if we have 12 volts on all the fuses that probably we have good ign and the fuse terminals r ok. then we will be ready for next step

I don't know where you are coming up with 10 volts, that's way low.

 

[TURBO200R4]

a circuit with 12.5 volts is good great ok bueno tits cant beat that.

a circuit with less that 10 volts bad poor no bueno trouble will let the smoke out probably will not work the relays.

 

[Mad Dog]

I’m talking to him on the phone. Let me add a piece to the puzzle, when the starter spins by connecting it with a wire the starter gear doesn’t engage the flywheel. I assume this is because the starter relay and solenoid isn’t energized, correct? I asked him to do it again and push the starter button to power the relay, the gears still didn’t engage...

 

[Son_Of_Dog]

Okay, here's the write up for what has been checked tonight:

Started off making the starter spin (did not turn over engine) by shorting from the positive terminal on the battery to the connection under the boot on the starter.
Tested the terminal under the boot for voltage, found no voltage.
Tested all fuses for voltage, all had good voltage.

Found the Diagnosis diagram on page 1.22 of the manual in @idk 's signature for the starting circuit and followed it out.
Came to the conclusion that the starter relay was faulty, replaced it.
After no results and further testing, all I can determine for sure is that the ground connection on the yellow/brown wire coming out of the ecu to the starter relay is intermittent, and that I cannot get the relay to click without directly powering it from the battery. When I bypass the starter relay, the starter turns the engine over (bike jumps forward if in gear).
The dash remained blank through all of this.

Potential diagnoses:
Some connection in the ecu is damaged, and not allowing a consistent ground in the starter relay.
Solenoid on the starter is damaged, causing the main connection from the battery to the starter to disconnect.
Ground on the starting circuit is intermittent, causing ecu to throw a code that does not allow the bike to function normally.

Let me know what you guys think, and thanks again for sticking with me on this.

 

[Steel]

Quickest way to diagnose ECU is to swap with @Mad Dog and see if that works. Don't know what years y'all have, so make sure they are compatible before swapping.

 

[EwoutR3]

Be carefull with that, you don't know what caused the assumed broken ECU. Maybe the cause of it is still present.

 

[idk]

Dirty contacts inside the solenoid and starter motor can cause problems as well. Not too difficult to open up and clean the bad contacts. Putting it back together may be a little more difficult.

However, if the bike starts when you use jumper cables from a car or truck then I would strongly suggest that the battery is not good. Remember, it is a big engine and a small battery, so not much headroom.

 

[Speedy]

Check ground wires' from relays and devices to the ECU main connectors for continuity. Neither the frame nor engine are used as a ground conduit. A broken or burnt wire could cause these symptoms. So could an ECU with a faulty ground internally. A service manual wiring diagram will show the circuits but not the locations in the wire harness. Check the battery ground terminal crimps and wires too.

 

[Son_Of_Dog]

I've been recommended to remove the starter and take it to the autoparts store and have it tested. How much of a pain is it going to be to remove and reinstall the starter? If I have to replace it, does anyone know what the alternative toyota starter is? I've seen in some other thread that some have replaced the starter with a very similar one by toyota.