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Discussion Starter · #1 ·
For a while I noticed my bike would momentarily cut out when cruising at low throttle positions at around 4500rpm ever since I got my Akra carbon exhaust and PCV. The problem feels like the injectors completely shut off until I twist a tiny bit more throttle to wake them up again. I always assumed it was just bad mapping for the PCV.

Last week I removed the PCV and had my bike tuned by Nels at 2Wheel Dynoworks, using a map for my exhaust. The problem still exists and now seems even worse. Yesterday I went for a long all day ride and the bike would cut out and stutter anywhere from 2500-4500rpm when holding the throttle steady at approximately 5-10% open position. When I increase the throttle the issue goes away.

I was texting with Nels about it last night and he thinks it's perhaps the throttle position sensor needs adjusting. Can anyone here comment on this? How would I go about adjusting the TPS if that's what is causing the issue?
 

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I was texting with Nels about it last night and he thinks it's perhaps the throttle position sensor needs adjusting. Can anyone here comment on this? How would I go about adjusting the TPS if that's what is causing the issue?
Your issue sounds like you need the o2 controller.

I have the same flash but with OEM exhaust & I am experiencing abrupt throttle when going open to close, close to open. Nels had me adjust the TPS, it helped but didn't fix my bikes problem.
 

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For a while I noticed my bike would momentarily cut out when cruising at low throttle positions at around 4500rpm ever since I got my Akra carbon exhaust and PCV. The problem feels like the injectors completely shut off until I twist a tiny bit more throttle to wake them up again. I always assumed it was just bad mapping for the PCV.

Last week I removed the PCV and had my bike tuned by Nels at 2Wheel Dynoworks, using a map for my exhaust. The problem still exists and now seems even worse. Yesterday I went for a long all day ride and the bike would cut out and stutter anywhere from 2500-4500rpm when holding the throttle steady at approximately 5-10% open position. When I increase the throttle the issue goes away.

I was texting with Nels about it last night and he thinks it's perhaps the throttle position sensor needs adjusting. Can anyone here comment on this? How would I go about adjusting the TPS if that's what is causing the issue?

Had this exact problem on my GSXR I had and adjusting the TPS fixxed the problem.
 

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could be a misadjusted/bad aps or tps or a vacuum leak.

check for the vacuum leak first, as you could have knocked something loose when hooking up the pcv and a vacuum leak especially at the map sensor will cause all sorts of low load running issues.
 

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Discussion Starter · #5 ·
could be a misadjusted/bad aps or tps or a vacuum leak.

check for the vacuum leak first, as you could have knocked something loose when hooking up the pcv and a vacuum leak especially at the map sensor will cause all sorts of low load running issues.
Where do I look for a vacuum leak? This stuff is all new to me..
 

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Where do I look for a vacuum leak? This stuff is all new to me..
pull the tank and airbox, by the throttle bodies there are a lot of little hoses, check to make sure there aren't any 'open' hoses or throttle body connections.

it really helps to have a copy of the service manual, as it details how everything should look and also how to run diagnostics on the sensors. if you google a bit you should be able to find a copy.
 

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Discussion Starter · #7 ·
pull the tank and airbox, by the throttle bodies there are a lot of little hoses, check to make sure there aren't any 'open' hoses or throttle body connections.

it really helps to have a copy of the service manual, as it details how everything should look and also how to run diagnostics on the sensors. if you google a bit you should be able to find a copy.
What about the throttle position sensor, where is that located?
 

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Discussion Starter · #9 ·
Check the PCV connectors for the injectors. I had a loose plug and had that issue.
I said in my original post that I removed the PCV and now have an ECU flash.
 

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What about the throttle position sensor, where is that located?
this is a ride by wire bike, so there are two throttle position sensors. one connected to the throttle cables (yamaha calls this the accelerator position sensor) and one connected to the throttle butterflies (throttle position sensor).

use diagnostics mode to check the aps and tps.

enter diagnostics mode: with the ignition key and engine run switch off, hold down 'select' and 'reset' on the instrument panel. turn the ignition key on and keep the buttons held down. after 8-10 seconds, display will show 'diag'. then release both buttons, and press and hold them down again. after 2 seconds, you'll see a big '1' and above that 'di' and a number.

the big number is the diagnostics code, the smaller number on top is the value. the 'select' and 'reset' buttons flip through the diagnostic codes forward and backward.

with code '1' displaying and the throttle grip closed, the little value should be between 11 and 21. turn the throttle full open, the value should be 96-106.
press the 'select' button a couple of times to change to code '13'. closed throttle value should be 9-23, full throttle should be 94-108.

if everything checks out, the tps (on the butterflies) is set correctly.

press 'select' to code 14. closed throttle values should be 12-22, full open should be 97-107. now with the throttle closed, very very slowly open the throttle. you should be able to hit each value from full closed to full open. if the values jump around, there's something wrong with the accelerator position sensor.
go to code 15. closed throttle should be 10-24, open throttle 95-109. do the slow throttle open test. same as above, you should be able to hit every value.

you can do the slow open test on the tps (codes 1 and 13), just be aware that it is normal for the values to jump up a little at the very beginning (when you hear the clicking sound). after that, the sensor should register every increment.

exit diagnostics mode by turning the key off.

if the tests all come out okay, the throttle sensors are fine.
 

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Discussion Starter · #11 ·
this is a ride by wire bike, so there are two throttle position sensors. one connected to the throttle cables (yamaha calls this the accelerator position sensor) and one connected to the throttle butterflies (throttle position sensor).

use diagnostics mode to check the aps and tps.

enter diagnostics mode: with the ignition key and engine run switch off, hold down 'select' and 'reset' on the instrument panel. turn the ignition key on and keep the buttons held down. after 8-10 seconds, display will show 'diag'. then release both buttons, and press and hold them down again. after 2 seconds, you'll see a big '1' and above that 'di' and a number.

the big number is the diagnostics code, the smaller number on top is the value. the 'select' and 'reset' buttons flip through the diagnostic codes forward and backward.

with code '1' displaying and the throttle grip closed, the little value should be between 11 and 21. turn the throttle full open, the value should be 96-106.
press the 'select' button a couple of times to change to code '13'. closed throttle value should be 9-23, full throttle should be 94-108.

if everything checks out, the tps (on the butterflies) is set correctly.

press 'select' to code 14. closed throttle values should be 12-22, full open should be 97-107. now with the throttle closed, very very slowly open the throttle. you should be able to hit each value from full closed to full open. if the values jump around, there's something wrong with the accelerator position sensor.
go to code 15. closed throttle should be 10-24, open throttle 95-109. do the slow throttle open test. same as above, you should be able to hit every value.

you can do the slow open test on the tps (codes 1 and 13), just be aware that it is normal for the values to jump up a little at the very beginning (when you hear the clicking sound). after that, the sensor should register every increment.

exit diagnostics mode by turning the key off.

if the tests all come out okay, the throttle sensors are fine.
I'll give this a go when I get some time this coming weekend. Sounds simple enough..
 

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OP, do you mean the rpms kind of dance when cruising on the highway? Like bouncing between fuel and no fuel. I have this "issue" with a fully stock '15
 

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Discussion Starter · #14 ·
OP, do you mean the rpms kind of dance when cruising on the highway? Like bouncing between fuel and no fuel. I have this "issue" with a fully stock '15
Yes the fuel cuts on and off abruptly almost like the bike is running out of fuel and is about to die but if I give a bit of throttle twist everything is fine. Just seems to be when the throttle is at very low percentages like 10% or less throttle, probably more like 5% actually.
 

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Yes the fuel cuts on and off abruptly almost like the bike is running out of fuel and is about to die but if I give a bit of throttle twist everything is fine. Just seems to be when the throttle is at very low percentages like 10% or less throttle, probably more like 5% actually.
when the fi is operating in closed loop it has lean surging, but you said that this started when you put on the pipe and the pcv, implying it wasn't there when the bike was completely stock.

kev's o2 controller will fix up the lean surging nicely, but your bike may have other issues.
 

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Discussion Starter · #16 ·
when the fi is operating in closed loop it has lean surging, but you said that this started when you put on the pipe and the pcv, implying it wasn't there when the bike was completely stock.

kev's o2 controller will fix up the lean surging nicely, but your bike may have other issues.

Correct, but the problem seems to have gotten much worse in the past 3 days. I also noticed today that my fan is turning on lower than it used to. The fan when stock would turn itself on at 106C(222F) and shut off at 100C(212F) but today I observed it turns on at 96C(205F) and shuts off at 91C(196F).

I had my last service done 5000kms (3000miles) ago and I was supposed to have the original plugs replaced but the dealer didn't have the plugs in stock at the time so I decided to wait until my next scheduled service, is it possible I have a faulty plug?

I ran through the diagnostic check earlier tonight for the throttle position sensors and everything checked out fine. But the bike seems to be getting worse by the day since Saturday.
 

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Your flash lowers the fan temp so don't worry about that.

Throw the o2 controller on there and see if it helps. If that doesnt help, talk to Nels with your findings.
 

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Discussion Starter · #18 ·
Your flash lowers the fan temp so don't worry about that.

Throw the o2 controller on there and see if it helps. If that doesnt help, talk to Nels with your findings.
So the O2 controller is a seperate piece of hardware I need to buy? Any recommended brands??
 

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I'm confused as to why one bike would exhibit this behavior, and another would not... Why would one bike need an O2 controller, and another not? I have the carbon Akra with Vcycle flash, and I do not have this issue in any mode.
 
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