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Discussion Starter #1
Went on this year's first local Wednesday ride and at about 40 miles in my bike went into "limp mode" and the FI light came on. As you may know, that is when it will run fine if you only tenderly open the throttle. Puled over shut it off poked, cursed, got back on. No light and it would accelerate as normal for about 2 miles. Then the light and limp.
Made it home okay (Limping still allows you about 70mph if you nurse it.) The next day was the same 2 mile limit before the light comes on. In dealer mode it shows two codes; c28 & c65. Engine temp normal. Voltage normal.

I've read through the forum and don't see a lot about it. I did find one thread where GreyWolf asked the victim if his bike would start without pulling the clutch lever in. (huh?) He answered yes, replaced the clutch-lever switch and the problem went away. Man GreyWolf was good. I never doubted him before and I have always robotically pulled the clutch to start. So I tried it and my bike would start without pulling the clutch. So that will likely fix the c65 code. But I can not believe that will cure the c28 which seems to be that the secondary butterflies are not opening.

AS for recent maintenance: I did, a few days before, replace both sprockets and chain. Cleaned the clutch push rod. Installed a new rear tire. I had put maybe 20 miles on the bike after that and before the failure.
On the internet, at large, I have found tons of older GSXR guys having the sensor fail from failed soldering. When I look at the parts fiche the V2 part
.SENSOR ASSY #13580-27G21 $89 looks different in design.

Any help?
Secondary Throttle Valve Actuator c28
 

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The position feedback for the secondary throttle valves passes through the connector on the top. I would check for an abraded short. I think this is the connector that was rubbing on the bottom of the tank that there has been so much discussion about. I'd have to check my bike to confirm.
 

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I should elaborate...

There is the throttle position sensor (#11) and there is the secondary throttle position sensor (#10) . The latter is the one that tells the ECM what position the secondary throttle butterflies are in. The latter is the higher of the two and the feedback circuit exits the sensor body through the connector on the top. Both of these sensors are on the left side rear corner of the rear throttle body. You'll have to lift the tank to see them.

There has been much discussion about the wires rubbing the bottom of the tank. On my Vee2 it was the wires as they exited the secondary throttle position connector that were at risk of rubbing on the tank. If the signal wires are fully or partially shorted to ground (or to each other) the ECM will get no signal or a false signal and cry about it.

I would start with a physical inspection of the wires on that connector.

Do you have a service manual?

Having trouble with site attaching photo... I will attempt to edit the photo into the post.
 

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Discussion Starter #8
Just so we all know, what year, mileage, ECU swapped? How's your battery?
Hi, ECU swapped, yes. The battery is original. It hasen't given any sign of trouble, the volt meter reads 14.1 but I have not had it tested for crank amps.
But I'm willing to swap it for a nearly new lithium that I have in my Honda as a test. Thanks
 

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Discussion Starter #9
Was the wiring loom in question, replaced for the associated recall?
Thanks. Those suspect wires were checked but deemed okay and just got some padding. But I got that all done very early on in the episode, so I'll check them again.
 

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Discussion Starter #10
Grimmer, No I don't have a service manual. (both your photos did publish) But I understand what you are saying.
You prompt a question:
I read somewhere that with the airbox exposed you can see the butterflies open and close when you turn on the key as a part of the pre-test. Do you know if that is true?
Also I will definitely check all the physical connections and wiring.
I'm still puzzled that it takes a few miles for it to fail. I guess that could be exposed wires heating up from partial contact, huh.


I should elaborate...

There is the throttle position sensor (#11) and there is the secondary throttle position sensor (#10) . The latter is the one that tells the ECM what position the secondary throttle butterflies are in. The latter is the higher of the two and the feedback circuit exits the sensor body through the connector on the top. Both of these sensors are on the left side rear corner of the rear throttle body. You'll have to lift the tank to see them.

There has been much discussion about the wires rubbing the bottom of the tank. On my Vee2 it was the wires as they exited the secondary throttle position connector that were at risk of rubbing on the tank. If the signal wires are fully or partially shorted to ground (or to each other) the ECM will get no signal or a false signal and cry about it.

I would start with a physical inspection of the wires on that connector.

Do you have a service manual?

Having trouble with site attaching photo... I will attempt to edit the photo into the post.
 

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Discussion Starter #11
It's this set of wires that could be the problem. I put extra protection around them and tied them down good:
Thanks blaustrom, that photo helps. I will be looking at and defending those wires.
 

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Grimmer, No I don't have a service manual. (both your photos did publish) But I understand what you are saying.
You prompt a question:
I read somewhere that with the airbox exposed you can see the butterflies open and close when you turn on the key as a part of the pre-test. Do you know if that is true?
Also I will definitely check all the physical connections and wiring.
I'm still puzzled that it takes a few miles for it to fail. I guess that could be exposed wires heating up from partial contact, huh.
Sorry it took so long... I've been arguing with a dirt bike clutch this afternoon.

Yes, the secondary throttle valves are the top most flap in the throttle bodies. You can see them with the airbox removed, and probably even with the bottom of the airbox in place with the filter removed. Look down the tube, if you can see a butterfly valve, that is the secondary throttle valve. (The primaries are on the bottom of the throttle bodies.)

I have added some annotations to the photo (I hope they are large enough to read). Probably the first thing to do is remove the airbox and turn on the ignition to see if they are moving. If they are moving, then I would check the feed back voltage. From there I would move to the DTC diagnosis procedures for checking the wiring between the ECM and the throttle body parts.

The procedure in the service manual for measuring the voltage across the feedback wires to adjust the position of the secondary throttle position sensor. (The primaries have a nice display in the instrument cluster, but the secondaries you have to go to the source with a multi-meter). You probably don't need adjust it, but you can try measuring the voltage to see if it is working. The manual says to unplug the bottom connector that causes them to move, turn on the ignition with the top connector still connected. And measure the voltage between the Y and B/Br wires while holding the secondary throttle valve completely closed with your finger. You should get approximately 0.6V. (I pushed some sowing pins into the top of the connector to get the multi-meter probes something to use.)

There are several other pages for testing for continuity and shorts in the wires between the ECM connector and the secondary throttle valve motor and sensor.
 

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Discussion Starter #13
Thanks very helpful. I could read the annotations by dragging the image to my desktop and enlarging.
I have it on the lift and the tank off ... I will need to do some more terrestrial things til Tuesday afternoon. But then I'm back at it.

Sorry it took so long... I've been arguing with a dirt bike clutch this afternoon.

Yes, the secondary throttle valves are the top most flap in the throttle bodies. You can see them with the airbox removed, and probably even with the bottom of the airbox in place with the filter removed. Look down the tube, if you can see a butterfly valve, that is the secondary throttle valve. (The primaries are on the bottom of the throttle bodies.)

I have added some annotations to the photo (I hope they are large enough to read). Probably the first thing to do is remove the airbox and turn on the ignition to see if they are moving. If they are moving, then I would check the feed back voltage. From there I would move to the DTC diagnosis procedures for checking the wiring between the ECM and the throttle body parts.

The procedure in the service manual for measuring the voltage across the feedback wires to adjust the position of the secondary throttle position sensor. (The primaries have a nice display in the instrument cluster, but the secondaries you have to go to the source with a multi-meter). You probably don't need adjust it, but you can try measuring the voltage to see if it is working. The manual says to unplug the bottom connector that causes them to move, turn on the ignition with the top connector still connected. And measure the voltage between the Y and B/Br wires while holding the secondary throttle valve completely closed with your finger. You should get approximately 0.6V. (I pushed some sowing pins into the top of the connector to get the multi-meter probes something to use.)

There are several other pages for testing for continuity and shorts in the wires between the ECM connector and the secondary throttle valve motor and sensor.
 

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Discussion Starter #15
Did you fix the clutch switch yet?
Yes I did but sadly that was unrelated. This morning I gave up after testing all the things Grimmer was so helpful with.
They ran their official diagnostic tool on it and it showed two additional codes, all in the fuel injection family. (the shop tool uses a different number system)
So after a while they decided that they needed a factory guy to conference in on it. Likely no answer til Tuesday. Stay tuned.
 

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Discussion Starter #16
GreyWolf was right again ! SOLVED

Just got a call from my dealer - my bike is ready and runs fine.

A few posts ago Bad Dad asked if I had fixed the clutch switch. I answered, yes. I took it out and cleaned some mild mung. Reinstalled it and the bike went back to not starting with the clutch lever out. But I didn't replace the switch. And yeah that was the problem. The dealer did all the same tests that Grimmer had suggested and then made a second call to the boys at HQ. They were told to replace the switch anyway just for good measure. Tah Dah !

It seems that the same core ECU (some variants) is used in the Gixers. Same problem. Same fix.

I know we tend to bad mouth dealers but I got to say that the guys at Powersports of Vallejo Vallejo, CA (707) 644-3756 hung in there. They did a lot of work and only charged me for the switch replacement.

And yes I have ordered a spare switch to live under the seat. It should be added to all the threads about "what spares do you carry".

Thanks Greywolf, still helping us.
 

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Thanks, good advice. This has been an issue for some, so I added it to my proactive replacement schedule.

Sent from my SM-G930V using Tapatalk
 

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I was in my local shop and got talking to the head guy about a Kawasaki they were having issues with and I suggested they replace the clutch switch.

It fixed the problem they had spent days chasing, it was a lesson for them and made me look like a genius.
 
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