subthrottle valve actuator stuck in a loop, bike won't start

[rpete]

I know there are a lot of bright members here, so I figured it wouldn't hurt to ask. The bike is a 2010 Z1000. I've searched for hours for any Kawasaki owner at all experiencing the problem, but no luck.

Maybe relevant, maybe not: I rode home in the rain one night, and the bike sat through a storm overnight.

The next morning the bike wouldn't start. It just cranked and cranked. A repeating loop can be heard, where a relay clicks, closing a circuit, the subthrottle valve actuator appears to attempt to move but doesn't, then brief silence, then the whole thing repeats, a few times a second. After ten seconds of this the FI warning is displayed and the service code is 39, ECU Communication Error.

A short video shows the difference in the actuator behaviour when the ignition is switched on, with the kill switch both on and off.



I've tried a new battery, this didn't help.

The placement of the R/R on this model leaves it vulnerable to the elements, and some owners find it can fail due to corrosion. I tried a new R/R, this didn't help. The original R/R passes all of the resistance tests anyhow.

I've tried a replacement ECU, this didn't help. I checked its power and ground connections, its continuity to the meter unit. All tests passed.

I've tested all of the relays and diodes in the relay box, they all pass.

Simply unplugging the subthrottle valve actuator should leave the valves open. When doing this, the relay continues the clicking cycle, without the actuator chatter of course. A bad actuator has its own service code, which I am not experiencing.

I had a Juice Box Pro and FCE connected, but I've put everything back to stock configuration and still the problem persists.

I've checked every electrical connection I can find, they all appear nice and clean.

So I'm out of ideas, does anyone know of something I might have missed? GBM can't have a look at the bike for the next two weeks. It's frustrating.

[rpete]

It took a while to find the cause, it ended up being corrosion inside the harness.

[carsick]

That's pretty heinous for a 4 year old bike. How long did it take to find? Diagnosed with resistance/voltage measurements or didja just pull everything apart until found?

[rpete]

I bought it as a leftover, so it has only been on the road for two years. Ivan (the guy who provides ECU reflashes for this bike) hasn't said how he went about finding it, but I believe that after everything else checked out he decided all that was left was to start cutting into the harness.

[scubasteveRR]

is the top picture how the harness looked when he cut it open,, looks pretty messy to be stock?

Also I has a similar issues with my CBR years ago, I had a service connector that was shorting out causing some where shit. took me a long time to find it but after I fixed it I had an issue with the starter relay that was hooked up to the wire I had the short on a couple years later. replaced that and haven't had an issue since.

Maybe you should look into a Cycleshell for your bike to keep it out of the rain. mine works wonderful!