What to do with my dumb broken motorcycle (I broke it)

Does the tps have 2 wires or 3? If three, make sure the ground reference is the exact same spot as the ECU ground reference. (The voltage divider has two variable resistors and three connections - one +5v in, one ground, and one variable in between the first two.) Wouldn't hurt to check that the +5 is also +5 relative to the same ground the ECU uses. 

If 2, it probably grounds through the body to the TB, and that is where my earlier comment came from that something is feeding voltage to the TB case instead of grounding the TB.

How about a new approach?  Pretend you don't have a check engine light available, or a voltmeter, or any diagnostic tools at all.  In that scenario, if I thought it was the TPS I'd run it with the sensor unplugged (it will run like that, right?) and see what changes.  I'd also check other, totally not what the computer is telling you but potentially troublesome things- clean fuel filter?  Good ignition connections?  Fuel injectors in good shape?  Throttle plates moving like they should?  No vacuum leaks?

I've chased my tail on stuff like this before and found that my problem was something was less convoluted than I thought- if nothing else, ruling out the simple crap should help you stay on target.

singleslammer said:

I might be able to make that happen.

This could be awesome!  If this ends up being the path to take, I can work on details.  Not sure who  else  is local that would want in on  the fun.  Probably won't be for a couple months.

¯\_(ツ)_/¯ said:

How about a new approach?  Pretend you don't have a check engine light available, or a voltmeter, or any diagnostic tools at all.  In that scenario, if I thought it was the TPS I'd run it with the sensor unplugged (it will run like that, right?) and see what changes.  I'd also check other, totally not what the computer is telling you but potentially troublesome things- clean fuel filter?  Good ignition connections?  Fuel injectors in good shape?  Throttle plates moving like they should?  No vacuum leaks?

I've tried that in the past.  Here's the thing; the bike flashes the FI light eight times, meaning MAP or related system fault, with the bike off.  Key On Engine Off, this thing is faulted.  So vac leaks and fuel filter aren't even in the equation. The ECU is flat not happy with that circuit.  

I need to get the battery charged and I can go from there.  I'll try to get the batt on a trickle charge for the weekend and maybe start seriously poking at it on Monday.

In reply to pres589 :

And you're certain it doesn't store codes?  Is there a way to clear them and see if it comes back?

When I was trying to fix this last time around, I could create a fault by pulling some other sensor, and then turn the bike on / engine off and see a different flash pattern added to the 8 flashes I already head.   Plug sensor back in with the bike off and then turn the key back to on and that would be gone.

That said, i don't know if I ever worked to clear codes.  Can try it.  I know that I never got to a situation where I could operate the throttle normally with the light blinking.  It seemed to stay faulted.

Bringing this thread back from the dead; I've got a wrench session to try and figure this dumb bike out! 

August 11th, Lawrence KS.  I've got a *MYSTERY GUEST* coming from out of town.  I'll let him self-identify if he wants to.  Anyone else want in on this?  I'll provide pizza or beer or whatever it takes.  If anyone else wants in on this chance to start an electrical fire and burn down my duplex, let me know, and I'll get you my address and such.  

It's ME!!! I offer help but zero skill or knowledge.