LCV issue

[active1951]

Originally Posted by hyper1685

would anyone be willing to use a multi meter to test the 6 terminals on the LCV connector and tell me what the readings should be when cold and at temp? The would help me figure out if the correct signals are getting to the LCV.

Any other thoughts?

Thanks,
Chris

Do you still have your old LCV to compare with your new LCV on any readings?
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[alanh]

Originally Posted by hyper1685

Ok. More trouble shooting. I reread the recommended pages in the service manual several times. My understanding is that if i turn the bike off with the key, the LCV should close completly. With this logic, I warmed the bike up, turned the bike off by the key and then disconnected the LCV wiring harness. I then turned the bike on to see if it would idle normally. the bike still was idling high (jumping between 1100 and 1400 rpms every few seconds). So the LCV is not closing. I put my finger over the LCV intake tube and it idled fine.

To answer a few of the above questions: the LCV i bought is a new OEM Yamaha part that i got at powersportsplus.com. I checked the onboard diagnostics and the engine and oil temp sensors seem to be reading normally. I could not get readings while the bike was runing so i could not see if the engine or oil temps were jumping around while the idle was jumping.

would anyone be willing to use a multi meter to test the 6 terminals on the LCV connector and tell me what the readings should be when cold and at temp? The would help me figure out if the correct signals are getting to the LCV.

Any other thoughts?

Thanks,
Chris

I would suggest you use your multi-meter and ring out Pins 21,22,43 & 44 for an open circuit.

You'll need to unplug the ECU and be aware that the (2) Red/Black wires in the LCV plug are LIVE with the key off so disconnect the battery terminal or pull the 10A Fuse #70 that powers the positive polarity of this device.

If you read my earlier contribution, LCV 101, it clearly states that the valve is sequenced by negative polarity via the ECU/cpu driver in a sequencial fashion and that's the reason why Pins 21-22 & 43-44 are opposite each other on the ECU plug. These outputs are triggered by solid state switches and possibly one of the wires is broken or poor contact.

Being that the LCV is a stepping motor, imo, it would be a crap shoot testing the resistance of the wires because the motor poles aren't in alignment but i've been wrong before.

• Did the cold and hot oil & engine sensor temp's check out correctly. Cold temp's should have been the same!

good luck
In my signature is a link to a comprehensive wiring diagram and ecu pin-outs

[alanh]

For those following this thread i have validated and checked the following from days gone bye and haven't thought to share this info until now

• The LCV on normal key-off shut-down overcloses and reopens slightly for assumed next cold start! This is done because the valve lacks feedback (open loop)
  • This can be proven by removing the aforementioned fuse in the prior response (#70) from a hot engine after normal shut-down. The engine will fast idle when started.
• Only after control goes to the oil temp sensor (OTS) does the valve close completely if the oil temp is satisfied.
  • This can be proven by starting a Hot bike. The engine will always fast idle momentarily until control goes to the OTS to close the device.