Unstable / Unhappy Idle when engine semi-warm

[seanmhc]

So for the past few months my bikes not been entirely happy, fuel mileage has dropped and this irregular idle problem has come out of nowhere.

When starting the bike while the engine is still warm, but not at full operating temperature, for instance leaving it off for 5 minutes and starting it again, I get a very unhappy idle. The engine sounds unhealthly making a loping sort of sound as the idle drops down to 900, sometimes 800 odd, then bouncing back to 1200, then 1100 etc.

When fully up to temperature, my idle steadies off and idles between 1200-1260 or 1260-1320 and sounds fine.

On a cold warm up the idle starts off at about 1400, then after a minute runs up at 1600-1700 before getting somewhere in the middle and up to temp.

It feels like the high idle is cutting off too early / before the engine is actually up to temperature and it's trying to idle normally without the engine temperature.

I've included a video here: https://youtu.be/mK4gB4TC2kM

So far I have done the following try solve the issue, Changed Spark Plugs, Changed Oil, Changed Air Filter, Synced throttle bodies, Upped the idle and played around with CO settings, all with no luck.

Anyone had experience of this / know what it is?

 

[TownsendsFJR1300]

Any after market fuel mapping installed?

What other mods to the bike?

Were the plugs sooty / black?

The bikes sounds rich (which would go along with bad mileage).

I would first, set the co #'s back to stock (hopefully you saved the original #'s)

 

[seanmhc]

Only thing that's been modified on the bike is the exhaust and that was done last year shortly after I got the bike. Only thing I had to do was up the idle a little and it ran fine.

Plugs looked spot on when I pulled them, tan coloured, none of them looked fouled.

CO settings are back to what they started with. I adjusted them to make them a little leaner as the exhaust was smelling really bad / rich and there was a load of popping going on.

 

[TownsendsFJR1300]

Only thing that's been modified on the bike is the exhaust and that was done last year shortly after I got the bike. Only thing I had to do was up the idle a little and it ran fine.

Plugs looked spot on when I pulled them, tan coloured, none of them looked fouled.

CO settings are back to what they started with. I adjusted them to make them a little leaner as the exhaust was smelling really bad / rich and there was a load of popping going on.

Somethings wrong in the throttle bodies. With what you've done, it shouldn't behave as such..

Finalimpact is way more familiar with the set up than I am,

He'll be here soon for what to check..
[MENTION=15974]FinalImpact[/MENTION]

 

[seanmhc]

Somethings wrong in the throttle bodies. With what you've done, it shouldn't behave as such..

Finalimpact is way more familiar with the set up than I am,

He'll be here soon for what to check..
[MENTION=15974]FinalImpact[/MENTION]

Yeah, it doesn't make much sense, it doesn't idle like that all the time, only when it's in the warming up phase just before it gets to temperature. I only ever notice it when I leave the bike for a bit and come to start it up with the engine half walm as in the mornings I usually start it, let it high idle for 30 seconds then I'm off rushing to work.

Thanks [MENTION=6338]TownsendsFJR1300[/MENTION]

 

[Motogiro]

Just off the top of my head, a place to start might be looking for a vacuum leak. Inspect the throttle body area and check to see all the vacuum line look present and healthy.

 

[TownsendsFJR1300]

Thinking about it, till Randy chimes in, there is a pressure regulator in the system.

There is also a schrader valve fitting to the fuel rail to check fuel pressure. It would probably be worth
checking the pressure especially when it's "acting up" and when it's not.

I thought as well that an injector may be leaking (kinda unusual) but your plugs were NOT black with soot...

 

[FinalImpact]

Interesting it was ok and now it's not. Honestly mine is just like that but it began when the ignition was advanced. Very happy when hot 200°F /90+C.

I personally don't see idle state affecting fuel economy so the fact that this took a hit implies something bigger changed. JM2C but when injectors leak, its real obvious. As for fuel pressure, also not likely as it would show up on the entire spectrum. I'm just saying springs don't get stronger so the pressure regulator can only bleed off more than it's supposed to vs gaining pressure.
If low on pressure it won't change based on a few minutes of engine temp change.

It does seem to run fine, yes? It pulls and sounds as it did but simple does not hold an even idle? Are these all true?
And btw, great first steps!

Today I spotted a mouse drop under the cover and lifted the tank to find a another clue. Sadly, being parked since Nov there were two penuts shelled in the airbox!!! Errrrr.....

Hint - did you look inside the airbox for foul play?

Anyway, any chance of trying fuel from a different supplier? And what does your coolant look like? Slim is the chance it is a factor, but everything written says it's temperature dependent and impacts fuel economy. ? What are the old vs current fuel ###'s?

 

[seanmhc]

Just off the top of my head, a place to start might be looking for a vacuum leak. Inspect the throttle body area and check to see all the vacuum line look present and healthy.

I've had a look at the hoses at the back of the air box earlier today and they all look intact, by eye anyway.

Thinking about it, till Randy chimes in, there is a pressure regulator in the system.

There is also a schrader valve fitting to the fuel rail to check fuel pressure. It would probably be worth
checking the pressure especially when it's "acting up" and when it's not.

I thought as well that an injector may be leaking (kinda unusual) but your plugs were NOT black with soot...

I can't say I've tried checking fuel pressure before, is that something that requires a particular set of tool? I'll see if my Haynes manual mentions anything and I'll have a look. My plugs were definitely not black when I swapped them out! Would have been nice if they'd have shown me anything but normal tan in colour, would have something to go off then haha!

Interesting it was ok and now it's not. Honestly mine is just like that but it began when the ignition was advanced. Very happy when hot 200°F /90+C.

I personally don't see idle state affecting fuel economy so the fact that this took a hit implies something bigger changed. JM2C but when injectors leak, its real obvious. As for fuel pressure, also not likely as it would show up on the entire spectrum. I'm just saying springs don't get stronger so the pressure regulator can only bleed off more than it's supposed to vs gaining pressure.
If low on pressure it won't change based on a few minutes of engine temp change.

It does seem to run fine, yes? It pulls and sounds as it did but simple does not hold an even idle? Are these all true?
And btw, great first steps!

Today I spotted a mouse drop under the cover and lifted the tank to find a another clue. Sadly, being parked since Nov there were two penuts shelled in the airbox!!! Errrrr.....

Hint - did you look inside the airbox for foul play?

Anyway, any chance of trying fuel from a different supplier? And what does your coolant look like? Slim is the chance it is a factor, but everything written says it's temperature dependent and impacts fuel economy. ? What are the old vs current fuel ###'s?

When I'm 3 bars up the temperature gauge the idle holds nice and steady at around 1300 give or take, on two or lower the idle seems to not be as happy and it's mainly noticeable after shutting off the engine and turning it back on after I've been riding, though the idle sounding more and more unhappy every time I turn the thing on.

Most of the time the bike runs fine, yes, though I've had a few issues recently where I've twisted the throttle and it's just bogged out for a moment or two and there wasn't it's usual get up and go. It seems to be just the idle not being happy!

Haha someone mentioned something like that with the airbox to me but they had a bird in theirs! Had a look and it's all clear!

As for fuel I never stick to a particular brand or type and that's never been an issue, I just fill up at the closest petrol station whenever my F trip ticks, I did even try some 'injector cleaner' fuel additive but that made not an ounce of difference either.

Coolant, well, I don't think that's been changed for a long time, flushed the system 4 times and put in some new fluid today. The old coolant was very very brown and looked black in the bucket. On the plus side, changing the coolant has made the engine feel much smoother when riding.. is that normal? Unfortunately, it's had no effect on the idle.

As for the fuel economy, I was getting a good 180-200 miles out of a tank, as of late, only 140, maybe 150.

 

[SandyN]

Mine has also suddenly developed the same problem and I've done exactly what the OP has.
After riding, on restarting, the idle drops to 800 and I get a stutter at 4000 rpm until it has been ridden a while.
I'm beginning to suspect the TPS and want to try clean it as per YouTube video on R6 TPS.
Any other advice would be appreciated.

Sent from my SM-A310F using Tapatalk

 

[TownsendsFJR1300]

IMO, there's an issue in the fueling system...

I use a product called Yamaha "RingFree" :https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

Its a fuel system and top end cleaner. It's extremely popular in the marine world. I run it in EVERY gas machine I own.

For SHOCK TREATMENT, it's mixed at 2 oz/ 1 gallon. Regular use is 1 oz / 10 gallons.

I would strongly suggest trying it. It cannot hurt anything and only help.


Here is a link, from a Yamaha outboard engine marine forum I frequent where the RF FIXED the OP's issue.

Post # 22 : https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

IE, should there be a partially clogged fuel passage, the RF in many cases solves it.
I do use it as well in my customers small machines(chainsaws, wee eater, generators, etc) to help clean out the fine passages(besides a sonic cleaner..

 

[FinalImpact]

All good info and clear answers. Thank you. Makes it easier even though their no clear solution ATM.

How many miles on both of the bikes in question???

If both are upwards of 45k mi / 72km there may be a mechanical factor of timing chain stretch and wear. As the chain stretches it retards cam timing events. This basically reduces the engines power even at idle. Adding in slack and slight bit of variation in cylinder balance (power produced by each cylinder) and it can cause that lope....

Now it comes down to how much effort are you willing to put into solving this?

One quick test is to unplug the coolant sensor once warm and see what it does. Going a step further if either of you could unplug a sensor and trick the ECU into thinking it is warmer than it is, this could help us understand the temperature effect. We would use a resistor of xxx ohms to tell it it is hotter/colder than it is. Most people don't have these laying around but they only cost a few cents. Shipping will cost more.


I can do the math, find the values and give you a link to order if you want to try. Our goal here would be to see if it is soley temperature reported to the ecu...

On my test bench is an FZ6 wiring harness, ecu, and my bikes gauge cluster.... below it thinks it is always 174°F.... This is 30 seconds of your time to test this.

Let me know. PS you would be out like 5$ for shipping...

Paste from another post. Notice temperature!

Project is presenting issues. Safety cut-off relay protocols to ground are sinking huge amounts of current. FSM doesn't mention anything of "resistance" to limit current and I have no need to buy a bike to have all factory parts needed to complete this. Taking a break!
It has been educational along the way and I did get it powered up w/out errors by faking many inputs with fixed nominal values. Some more elaborately than others. lol


Someone put a throttle grip on this! TPS input. Ha!

Reads as Diagnostic: 01 = 10 & 111. Not bad for a hack!


Fitting for the days end.... yep!

View attachment 67706View attachment 67707

 

[seanmhc]

IMO, there's an issue in the fueling system...

I use a product called Yamaha "RingFree" :https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

Its a fuel system and top end cleaner. It's extremely popular in the marine world. I run it in EVERY gas machine I own.

For SHOCK TREATMENT, it's mixed at 2 oz/ 1 gallon. Regular use is 1 oz / 10 gallons.

I would strongly suggest trying it. It cannot hurt anything and only help.


Here is a link, from a Yamaha outboard engine marine forum I frequent where the RF FIXED the OP's issue.

Post # 22 : https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

IE, should there be a partially clogged fuel passage, the RF in many cases solves it.
I do use it as well in my customers small machines(chainsaws, wee eater, generators, etc) to help clean out the fine passages(besides a sonic cleaner..

Just had a little look and I can't find it sold anywhere online, is this a popping down to the Yamaha store jobby? May be worth a try.

All good info and clear answers. Thank you. Makes it easier even though their no clear solution ATM.

How many miles on both of the bikes in question???

If both are upwards of 45k mi / 72km there may be a mechanical factor of timing chain stretch and wear. As the chain stretches it retards cam timing events. This basically reduces the engines power even at idle. Adding in slack and slight bit of variation in cylinder balance (power produced by each cylinder) and it can cause that lope....

Now it comes down to how much effort are you willing to put into solving this?

One quick test is to unplug the coolant sensor once warm and see what it does. Going a step further if either of you could unplug a sensor and trick the ECU into thinking it is warmer than it is, this could help us understand the temperature effect. We would use a resistor of xxx ohms to tell it it is hotter/colder than it is. Most people don't have these laying around but they only cost a few cents. Shipping will cost more.


I can do the math, find the values and give you a link to order if you want to try. Our goal here would be to see if it is soley temperature reported to the ecu...

On my test bench is an FZ6 wiring harness, ecu, and my bikes gauge cluster.... below it thinks it is always 174°F.... This is 30 seconds of your time to test this.

Let me know. PS you would be out like 5$ for shipping...

Paste from another post. Notice temperature!

My bike has just ticked over 25,000 miles, so I'm not quite at your 45k mark yet!

Now we're delving into the world of things I've not done to the bike before, but I'm all for learning and trying to figure it out, albeit is it finding the time too but that's not so difficult right now. Unplugging the coolant sensor, shouldn't be too difficult if it' just the case of unplugging a wire somewhere!

I'm more than happy to try out tricking the ECU, though I'd need a real walk through as electronics isn't my strong point, I get the principles but in practice connecting and soldering things never goes my way! I'd like my bike to be back healthy as it really is the perfect machine for me..

 

[TownsendsFJR1300]

Just had a little look and I can't find it sold anywhere online, is this a popping down to the Yamaha store jobby? May be worth a try.

https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

https://www.amazon.com/s/ref=nb_sb_...a&sprefix=ringfree,aps,180&crid=25H6Z07ZBFGWL


It's sold at almost ALL Yamaha MARINE dealerships.. Very, very popular in the marine world

I use it in EVERY gas machine I own, including the bike,

 

[seanmhc]

https://www.shopyamaha.com/product/details/ring-free-plus?b=Search&d=34

https://www.amazon.com/s/ref=nb_sb_...a&sprefix=ringfree,aps,180&crid=25H6Z07ZBFGWL


It's sold at almost ALL Yamaha MARINE dealerships.. Very, very popular in the marine world

I use it in EVERY gas machine I own, including the bike,

It appears the product is unheard of in the UK. I can try get some shipped out from the US albeit very pricey if you believe it will make a difference!

 

[TownsendsFJR1300]

It appears the product is unheard of in the UK. I can try get some shipped out from the US albeit very pricey if you believe it will make a difference!

One oz treats 10 gallons NORMALLY.

Shock treatment is TWO oz / ONE gallon.

IME, yes it does work that well. I use it on my customers small engines as well.


Read post #22 specifically here: Yamaha 150 TRXC vibration issue - Yamaha Outboard Parts Forum

The RF FIXED his running issue WITHOUT DOING ANYTHING ELSE...

 

[SandyN]

Ok, it seems that my problem has been resolved...

Together with the intermittent drop in idle rpm's I also noticed that the fuel pump priming sound didn't sound normal. Also over the previous two weeks the starter was cranking slower. I checked the battery and the charging rate ( but not under load) and everything seemed normal..

On Saturday the battery packed up (13 months old!!) and had to be replaced.

I replaced it with a Motobatt and Voila! no more idling problems. So, it would seem that the idle is rather dependant on current draw? If the battery is not delivering what is required, the idle is affected.

It would be interesting to see if Seanmhc's problem could also be sorted by installing a new battery.

 

[TownsendsFJR1300]

A bad battery can and will cause all kinds of issues... (as you've noted).

Basic tests, such as LOAD testing a battery is OFTEN recommended, just to rule it.

Checking your charging voltage after the battery is ruled good is also necessary.

The ECU, without the proper power to it is not happy and WILL show it...


But please, in the future, post ALL abnormalities (slow cranking) would have brought up battery issues (which NEVER were suspected).

But thanks for the updates and that your in the saddle again!