2021 yxz ss idling/throttle issue

2208 Views 17 Replies 5 Participants Last post by Tschultz, 4 d ago

Tschultz

Discussion Starter · 1 mo ago (Edited)

I purchased a brand new 21 yxz ss with a dealer installed gen 2 gytr kit almost a year ago. A few months into owning it, it would die when coming to a stop, I could prevent it from dieing by tapping the throttle. Ran fine on top end. Long story short brought it to a dealer and they tore it all the way down to the crank and said it had low compression due to dirt getting in it even though it only had 40 hours and only went on a few trips. Yamaha didn’t warranty it.

I sent the engine off to Alba racing for a build, just got it in and I’m still having the same issue as before! Idles just fine on start up but if I rev it up and let off the throttle it dies. If I try starting it right after it dies it’ll crank for a while before it starts. Also feels like the throttle lags behind the input.(the throttle “lag” is a new problem but I had the cable off the throttle body so I’m sure that’s related to that issue)

just looking for some ideas on what to look for and what/how to test it. Could it be injectors?

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WWARt

· #2 · 1 mo ago

Go thru the clutch actuator bleed process. If its not followed to the letter it will do exactly what you described. Check the shop manual carefully !!

Since I just went thru the exact same thing this weekend. And its not a common thing for the maintenance techs. I would hedge that it wasn't done correctly by the dealer.

Having been a mechanic an instructor and finally running maintenance operations for the US Army. And been doing this for going on 40 years. Always start with the simplest before you go down the expensive path.

Oh, and don't skip the step where you raise the rear end and shift (successfully) between neutral and first 10 times. But don't bleed the clutch with the ass end in the air. It won't work.

Nate

Tschultz

Discussion Starter · #3 · 1 mo ago

WWARt said:
Go thru the clutch actuator bleed process. If its not followed to the letter it will do exactly what you described. Check the shop manual carefully !!

Since I just went thru the exact same thing this weekend. And its not a common thing for the maintenance techs. I would hedge that it wasn't done correctly by the dealer.

Having been a mechanic an instructor and finally running maintenance operations for the US Army. And been doing this for going on 40 years. Always start with the simplest before you go down the expensive path.

Oh, and don't skip the step where you raise the rear end and shift (successfully) between neutral and first 10 times. But don't bleed the clutch with the ass end in the air. It won't work.

Nate

I found it in the manual I’ll give it a try and let you know if it works, might need to get some tools. Could I take the shaft off the flywheel that connects the trans to the engine to see if that’s the issue that way? Not sure how it works just a thought

WWARt

· #4 · 1 mo ago

Only tools would be a vacuum pump, 6 mm open end wrench , 4mm Allen key socket (IIRC) and something to keep the rear end safely off the ground.

One thing the manual won't tell you is that if you leave the socket wrench in the manual clutch when you turn on the key it will throw the wrench at you.

The one part that seems to trip people up is that you need to cycle the manual clutch engage and bleed from both positions. The other one no one seems to pay attention to is the "If your getting lots of little bubbles, let it sit for an hour or more before continuing."

It would take longer to disconnect the drive shaft than to bleed the clutch. You only need to pull the upper left console plastic to do the clutch, though its easier to go ahead and remove both right and left upper console sides. It also makes it easier to have a helper man the vacuum pump while you open and close the bleeder valve. This way you have someone who can keep an eye on the fluid level in the clutch reservoir.

Nate

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Tschultz

Discussion Starter · #5 · 1 mo ago

WWARt said:
Only tools would be a vacuum pump, 6 mm open end wrench , 4mm Allen key socket (IIRC) and something to keep the rear end safely off the ground.

One thing the manual won't tell you is that if you leave the socket wrench in the manual clutch when you turn on the key it will throw the wrench at you.

The one part that seems to trip people up is that you need to cycle the manual clutch engage and bleed from both positions. The other one no one seems to pay attention to is the "If your getting lots of little bubbles, let it sit for an hour or more before continuing."

It would take longer to disconnect the drive shaft than to bleed the clutch. You only need to pull the upper left console plastic to do the clutch, though its easier to go ahead and remove both right and left upper console sides. It also makes it easier to have a helper man the vacuum pump while you open and close the bleeder valve. This way you have someone who can keep an eye on the fluid level in the clutch reservoir.

Nate

I ordered the vacuum pump and still plan on bleeding it once it gets here Wednesday, but since I already had the tools out and plastics off I took the shaft off the flywheel. Started normal but still has the same issue when not connected to the trans.

It did throw a code this time of “37” which is the idle speed control valve

WWARt

· #6 · 1 mo ago

FYI, be careful not to turn the engine backwards. They're know for jumping time when rotated backwards.
Nate

Tschultz

Discussion Starter · #7 · 25 d ago

Yup! Never backwards, has a manual tensioner as well.
Update, ended up ordering a new throttle body. It comes with all new sensors, vacuum lines, fuel rail and injectors. Got it in tonight and seems to have significantly helped, it did die on me once but the fuel is 10 months old now so I’ll be putting fresh fuel in it tomorrow and taking her for a drive.

WWARt

· #8 · 25 d ago

Remember, even 91 octane without ethanol is aerobic and WILL absorb moisture from ambient air.

If the fuel has sat that long it would be best to drain any remaining fuel. Flush the tank (swish with fresh fuel around and drain). And refill with fresh fuel.

It may seem "over kill" but considering that were talking about only a couple bucks for fuel and only a few minutes to flush the tank... Its an inexpensive fix compared to what you have invested so far.

Keep in mind I wear a belt and suspenders... LOL

Nate

Tschultz

Discussion Starter · #9 · 22 d ago

WWARt said:
Remember, even 91 octane without ethanol is aerobic and WILL absorb moisture from ambient air.

If the fuel has sat that long it would be best to drain any remaining fuel. Flush the tank (swish with fresh fuel around and drain). And refill with fresh fuel.

It may seem "over kill" but considering that were talking about only a couple bucks for fuel and only a few minutes to flush the tank... Its an inexpensive fix compared to what you have invested so far.

Keep in mind I wear a belt and suspenders... LOL

Nate

I drained all the fluid from the tank filled with fresh 91. Runs a lot better sounds very healthy. Fuel definitely was bad from sitting while the engine was pulled.

However It has died on me a few times, it only seems to do it now when It’s still warming up. I’ve put on 40miles in 3 trips just on the roads near me and it’s done it each time.

only thing left to replace would be fuel pump and coils lol. There’s a way to check all that In the manual before I get too carried away

TJV250R

· #10 · 22 d ago

I was thinking about this, and my 2019 would die sometimes when it was hot and I was trying to maneuver around a tight spot. Then one day it just sputtered and finally died when I was slowing down. I tried pumping the gas and it almost worked to keep it running. I pulled the fuel pump and messed with it. Lubed it up and tried it. It ran just fine from there. I did replace the fuel pump before the next big ride though. I have not had an issue since.

Tschultz

Discussion Starter · #11 · 12 d ago

TJV250R said:
I was thinking about this, and my 2019 would die sometimes when it was hot and I was trying to maneuver around a tight spot. Then one day it just sputtered and finally died when I was slowing down. I tried pumping the gas and it almost worked to keep it running. I pulled the fuel pump and messed with it. Lubed it up and tried it. It ran just fine from there. I did replace the fuel pump before the next big ride though. I have not had an issue since.

I tried a new fuel pump and didn’t solve the issue, it’s still doing the same thing. I pulled the coils out and they read 1.6 ohm to the primary and 9.6k ohm to the secondary which is within spec and the rubber appears to be in great shape, so don’t think I have an issue there.

Not sure what else to do..whole engine is freshly rebuilt, new throttle body which comes with every sensor that runs the engine basically, fuel pump, and coils are fine.

Before I brought it to the dealer the first time almost a year ago, I had went back to the stock gytr tune and it didn’t help at all still the same issue so it’s not a tune issue. Any ideas what to try next?

On the bright side I’ll have enough spare parts to build another yxz lol

WWARt

· #12 · 12 d ago

I know this is probably not going to be at all helpful. But, hey, thats me.

BLUF. Engines need 3 things. Fuel Air Fire. When those three aren't present, it doesn't run. When those 3 aren't in balance, then the engine doesn't run in balance.

Try and reduce each "symptom". Then see where the symptoms coincide.

You said it dies on return to idle. Except when you hold in additional throttle. If that were the only symptom, that would indicate that the throttle curve was too steep on throttle reduction.

But, does it take too long and cool to spool up (ls it too rich fuel)? Is it too warm on spool up (Too lean).

I would say plug in an O2 sensor and look at your results.

At the same time. And I know this may be insulting, but it needs to be said. If not to you, then to others who come along later.

Clean air filter? Primary? Secondary? Clean fuel? Clean fuel filter? Flushed ALL fuel lines? Proper fuel pump output? Proper timing?

Sorry. But it does come down to Fuel, Air, Fire. That is, as long as suck, squeeze, bang, blow are in sequence and in the proper ratio.

Nate

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Tschultz

Discussion Starter · #13 · 12 d ago

WWARt said:
I know this is probably not going to be at all helpful. But, hey, thats me.

BLUF. Engines need 3 things. Fuel Air Fire. When those three aren't present, it doesn't run. When those 3 aren't in balance, then the engine doesn't run in balance.

Try and reduce each "symptom". Then see where the symptoms coincide.

You said it dies on return to idle. Except when you hold in additional throttle. If that were the only symptom, that would indicate that the throttle curve was too steep on throttle reduction.

But, does it take too long and cool to spool up (ls it too rich fuel)? Is it too warm on spool up (Too lean).

I would say plug in an O2 sensor and look at your results.

At the same time. And I know this may be insulting, but it needs to be said. If not to you, then to others who come along later.

Clean air filter? Primary? Secondary? Clean fuel? Clean fuel filter? Flushed ALL fuel lines? Proper fuel pump output? Proper timing?

Sorry. But it does come down to Fuel, Air, Fire. That is, as long as suck, squeeze, bang, blow are in sequence and in the proper ratio.

Nate
[/QUOTE

The throttle body itself helped a ton, really cleaned up the idle but didn’t solve the issue just made it happen less frequently.

It acts like it’s running on 2 cylinders then I can get it to snap out of it by giving a little gas.

As far as spooling up it’s very quick to spool and lacks no power at all. I’d say it runs rich, after a higher rpm pull I’ll get the occasional exhaust pop/back fire or between shifts of a pull.

I have no idea about the O2 sensor, from my understanding the gen 2 gytr kit doesn’t come with one. I didn’t do the original install on the kit so I don’t have instructions. There is a sensor on the end of the intake plenum, not sure what that one is for.

It has a new gytr air filter, clean fuel, no blockage in the fuel lines, everything from the fuel pump, injectors and fuel rail is brand new and the engine was built by Alba racing so timing is good.

I tried to share the video I posted but didn’t go through so I’ll post the link instead

youtube.com

Yxz idle issue

youtube.com

fortrdb

· #14 · 12 d ago

Replace all the damn coils. They measure good on a bench, but have issues......

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WWARt

· #15 · 12 d ago

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Tschultz

Discussion Starter · #16 · 9 d ago

Replaced all 3 coils with new oem and still has the same issue. Took it for a 30min drive, ran good lots of power, coming to a stop does the same thing drops from 1500 rpm down to 1000 so I put it in neutral and give it a little throttle and it snaps out of it.

Very frustrated with the machine, not sure what to try next. It’s had this issue since the day I got it

youtube.com

Yxz idle issue after coils

youtube.com

brett

· #17 · 9 d ago

Tschultz said:
Replaced all 3 coils with new oem and still has the same issue. Took it for a 30min drive, ran good lots of power, coming to a stop does the same thing drops from 1500 rpm down to 1000 so I put it in neutral and give it a little throttle and it snaps out of it.

Very frustrated with the machine, not sure what to try next. It’s had this issue since the day I got it

Yxz idle issue after coils

youtube.com

Buy yourself FT ECU, read your map then go into ecu settings and add 100 rpm to the base idle speed.

Tschultz

Discussion Starter · #18 · 4 d ago

I talked with Nate over at Alba, he gave me a few things to try. I adjusted the idle screw on side of the throttle body in a turn and it won’t die when coming to a stop now. It did however die when giving it throttle from a stop once. I played with it a bit and got it to not die when idling and coming to a stop consistently. I haven’t put hard miles on so time will tell.

So kind of fixed one issue but created another, not sure if it’s throttle cable related because it’s almost like the first inch of pressing the pedal does nothing. I see they make kits to eliminate the dead spot, might just throw a big zip tie in and call it good lol

Almost just seems like a tune issue at this point, might have Nate tweak some stuff or try a different tuner. Dlp might be who I try as they aren’t too far from me, few hour drive so they might be able to dial it in a little better.

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