Rough idle and hard to start when warm - sometimes!

[dazzler24]

My bike, 2015 model, has always been a reliable starter whether hot or cold.  One press of the starter and it would fire up,  without touching the throttle, and then idle as expected.

In recent months it's had difficulty in starting after it's warmed up (sometimes 3 or 4 goes) and then that usually is accompanied by a bit of a 'lumpy cam' idle (think sound of a horse galloping) if you know what I mean after which the idle settles to a steady 1200 rpm or thereabouts.  I sometimes have to apply some throttle to get it to catch in these cases.

I recently, 2 days ago, did a throttle body sync thinking that may have contributed to the problem but I'm still experiencing the same issue.  The sync was out a little to start with before adjustment but not too bad.

While there, I checked the rubber caps over the vacuum tubes for any cracks/leaks and they all appeared OK.

• Today I checked my diags and had two fault codes come up in history.  The results below: -

DIAG 60 - 00 (no current faults)

DIAG 61 - 12 (Crankshaft position sensor: no normal signals are received ) and 60 (YCC-T drive system: malfunction detected)

DIAG 62 - 02 (number of fault codes detected.  So only the two above)

• I had done the APS 'mod' some years ago and thought I'd recheck the numbers again in case they'd moved out of the range.  They have not changed and are as per the orange column below. 

 

I am also due soon (voluntary) for my 2nd check of the valve lash at 33,000 kms.  I didn't do any adjustment at the first early check at ~20,000 kms as they were all in spec (See below).

 

So, this leads me to ask these questions from the learned here: -

• Is it possible tightening exhaust valves will give me the symptoms as described when warm?
• Possible dirty contacts/connector in crankshaft position sensor cct?
• Should I try a reset of the ISC (Idle Speed control) DIAG code 67?
• O2 sensor?
• Other suggestions.....?

Thanks for any help offered.

[skipperT]

-yes, check the valve lash. 
-possible, but doubtful. I think your ckp code is a red herring possibly, clear it and let’s see if it trips again. If it does you’ll need a pickup coil. Worth checking the connection, yes but it’ll probably be clean. 
-sure but no. I’d wait until valve lash checked/corrected/ and sync re-adjusted (if valves are out) in addition to cleaning the carbon from the throttle bodies, and new plugs. After that reset the idle learning. 
-doubtful 02, FJ ECM ignores the output at startup. 
 

Mines done that since new. Intermittent at best and unpredictable as far as the warm re-start and a smooth idle goes. 

-battery health and charge, weak fuel pump, clogged vents or vent lines from fuel tank, do you have a charcoal canister in your neck of the woods? All that also comes to mind. 

-Skip
 

[dazzler24]

1 hour ago, skipperT said:

-yes, check the valve lash. 
-possible, but doubtful. I think your ckp code is a red herring possibly, clear it and let’s see if it trips again. If it does you’ll need a pickup coil. Worth checking the connection, yes but it’ll probably be clean. 
-sure but no. I’d wait until valve lash checked/corrected/ and sync re-adjusted (if valves are out) in addition to cleaning the carbon from the throttle bodies, and new plugs. After that reset the idle learning. 
-doubtful 02, FJ ECM ignores the output at startup. 
 

Mines done that since new. Intermittent at best and unpredictable as far as the warm re-start and a smooth idle goes. 

-battery health and charge, weak fuel pump, clogged vents or vent lines from fuel tank, do you have a charcoal canister in your neck of the woods? All that also comes to mind. 

-Skip
 

Thanks Skip.  As usual I always appreciate your input.

• Right, valve lash now on the top of the priority list.
• OK - codes cleared.  I'll keep an eye out for any return.
• Did you see that I also had an error code 60 (YCC-T drive system: malfunction detected) as well?
• Just so I'm clear, are you suggesting that I remove the throttle bodies and give them a good clean no matter what - or only if the valve lash adjustment (if needed) doesn't fix the issue?
• I did change plugs only 10K kms ago?  Recommendation is every 20K kms or change again are you suggesting?
• Regarding O2, I do have KevTx's O2 in line kit and have had since 'forever'.  Don't know if that's a consideration?
• No charcoal canister over here. To paraphrase @2and3cylinders- "We don't need no stinkin' canisters!"🤣

Interesting that yours has done this since new.  Maybe I'm overthinking it but it's just that it's been so predictable on start-up over the years that the change is noticeable for me.

Anyway, thanks again as always and while I don't want to burden you with questions, I'm hoping (selfishly) that it helps to pass the time while you're laid up getting that hip repaired.

Cheers for now.

 

[2and3cylinders]

Hmmmm?

Interesting 

KUITL

[skipperT]

On 6/19/2024 at 6:25 AM, 2and3cylinders said:

On 6/19/2024 at 6:25 AM, 2and3cylinders said:

Hmmmm?

Interesting 

KUITL

Ok @2and3cylinders you’ve got me on that one…. What’s the abbreviation for? Google says it’s Hindi for roof or crooked. 🤣

-S

Edited June 21 by skipperT

[2and3cylinders]

2 hours ago, skipperT said:

Ok @2and3cylinders you’ve got me on that one…. What’s the abbreviation for? Google says it’s Hindi for roof or crooked. 🤣

-S

Keep Us In The Loop

Brilliant 👏 

[skipperT]

On 6/19/2024 at 12:41 AM, dazzler24 said:

Thanks Skip.  As usual I always appreciate your input.

• Right, valve lash now on the top of the priority list.
• OK - codes cleared.  I'll keep an eye out for any return.
• Did you see that I also had an error code 60 (YCC-T drive system: malfunction detected) as well?
• Just so I'm clear, are you suggesting that I remove the throttle bodies and give them a good clean no matter what - or only if the valve lash adjustment (if needed) doesn't fix the issue?
• I did change plugs only 10K kms ago?  Recommendation is every 20K kms or change again are you suggesting?
• Regarding O2, I do have KevTx's O2 in line kit and have had since 'forever'.  Don't know if that's a consideration?
• No charcoal canister over here. To paraphrase @2and3cylinders- "We don't need no stinkin' canisters!"🤣

Interesting that yours has done this since new.  Maybe I'm overthinking it but it's just that it's been so predictable on start-up over the years that the change is noticeable for me.

Anyway, thanks again as always and while I don't want to burden you with questions, I'm hoping (selfishly) that it helps to pass the time while you're laid up getting that hip repaired.

Cheers for now.

 

Anytime brother, as I mentioned many years ago I love the puzzles they keep me thinking, and I HATE the spread of false information. Which is why I jump in and try to share correct info at times while hoping not to come across as a “know it all” git cause I certainly am not. Part of this career is learning something every day. 

-good, yes. Make it so. Set the exhausts as loose as you can, I usually shoot for 0.29-0.30mm (if memory serves) my bet is they’re tight. 
-I did see that, but I wouldn’t sweat it unless it trips again. 
-I clean my TB’s every time I adjust valves. Just me being anal, but it’s literally 3 clamps after you’ve got the airbox off - plus some electrical connections. Takes 5 minutes. But anyway I wouldn’t reset that “learned” idle value until I knew that valves were in spec, TB cleaned and synced. 
-Skip the plugs if they’re that new. Same with the o2 I wouldn’t sweat that either. 

A good baseline is worth striving for before chasing your tail. That said don’t forget about a charged and good battery. Don’t assume it’s good just because it’s new. If tested with a VOM indicates 12.6-12.7v or less after charging, it’s a questionable battery and I’d pursue that line of troubleshooting further. These bikes are sensitive and need a good strong battery. 

HTH, sorry meant to send this when I wrote it this morning! 
-S

 

[2and3cylinders]

I cleaned the TB as part of my last Major service and replaced the throttle cables while I was at it given there was 65k miles on them.  I also did the reduce throttle effort mod as well but next time under the hood may add another threaded hole for the spring stop screw because now it's a bit too easy to twitch the throttle during hot runs and traversing bumpy roads.

Not sure I cleaned them quite correctly but treated them like carburetors. It wasn't as easy as I thought it'd be, and I didn't want to stress the butterfly assemblies. Carb cleaner didn't seem to wash off the light carbon film but it did wipe off eventually.

Not sure cleaning them made much of a difference...

For some reason after I had trouble synchronizing them accurately?

 

[dazzler24]

1 hour ago, skipperT said:

Anytime brother, as I mentioned many years ago I love the puzzles they keep me thinking, and I HATE the spread of false information. Which is why I jump in and try to share correct info at times while hoping not to come across as a “know it all” git cause I certainly am not. Part of this career is learning something every day. 

-good, yes. Make it so. Set the exhausts as loose as you can, I usually shoot for 0.29-0.30mm (if memory serves) my bet is they’re tight. 
-I did see that, but I wouldn’t sweat it unless it trips again. 
-I clean my TB’s every time I adjust valves. Just me being anal, but it’s literally 3 clamps after you’ve got the airbox off - plus some electrical connections. Takes 5 minutes. But anyway I wouldn’t reset that “learned” idle value until I knew that valves were in spec, TB cleaned and synced. 
-Skip the plugs if they’re that new. Same with the o2 I wouldn’t sweat that either. 

A good baseline is worth striving for before chasing your tail. That said don’t forget about a charged and good battery. Don’t assume it’s good just because it’s new. If tested with a VOM indicates 12.6-12.7v or less after charging, it’s a questionable battery and I’d pursue that line of troubleshooting further. These bikes are sensitive and need a good strong battery. 

HTH, sorry meant to send this when I wrote it this morning! 
-S

 

You're not seen as a "know it all" skipper as your advice to all and sundry here over a very long period has proven to be both accurate and coming from a background of long experience.  But I'll stop now in case I'm seen as trying to ingratiate myself.😉

Thanks for the advice and answers to my questions and addressing the throttle body clean on another recent thread and mentioned here as well.  I wasn't going to remove the throttle body but on reconsideration, I'm going to pull it completely out for it's first inspection and clean after 30,000kms.😲

OK, I see that the service manual states that if the throttle bodies are removed then the ISC (CODE 67) should be relearned on re-installation.   I note that it states to do that first before the sync?  Do you prescribe to that or do you do it as per your recommendation above? 

The EX valves weren't too bad - #1 and #2 cyls were ~0.27mm on all four valves with #3 both a tight 0.26mm.

So yes, getting onto the tight end of the scale so I am now hunting down some fine tolerance shims to get that magic 0.3mm gap.  And to assist with that, I might be able to do some shuffling of the oddball Yamaha shims to get where I want to be.

Interesting advice about the battery voltage.  I will check.

Again, thanks. 

 

[dazzler24]

51 minutes ago, 2and3cylinders said:

INot sure cleaning them made much of a difference...

For some reason after I had trouble synchronizing them accurately?

Agghhh.... don't tell me that!

[skipperT]

21 hours ago, dazzler24 said:

 

OK, I see that the service manual states that if the throttle bodies are removed then the ISC (CODE 67) should be relearned on re-installation.   I note that it states to do that first before the sync?  Do you prescribe to that or do you do it as per your recommendation above? 

The EX valves weren't too bad - #1 and #2 cyls were ~0.27mm on all four valves with #3 both a tight 0.26mm.

So yes, getting onto the tight end of the scale so I am now hunting down some fine tolerance shims to get that magic 0.3mm gap.  And to assist with that, I might be able to do some shuffling of the oddball Yamaha shims to get where I want to be.

Interesting advice about the battery voltage.  I will check.

Again, thanks. 

 

Anytime. Cheers Daz!
and yes you’re correct, I didn’t realize the manual had specific sequence of events. So reset THEN sync. Makes sense. 
-S

[dazzler24]

OK.. so, thought I'd close this loop and address the original subject line of my thread in the hope that it might help someone else who has, or will experience the symptoms that I'd been having.

So, after wisely listening to the experts in this thread, here is the work I performed on the bike :-

• Adjusted exhaust valve lash to max (0.3mm) - all of them.
• Cleaned throttle bodies (in situ).
• Re-adjusted throttle body sync.
• Added 15mls of Yamaha's Ring Free Plus to a tank full of fuel.

I finally had the chance to take it for a quick ~200km strap today after completing the above tasks and while it's only one outing my bike is back to its usual self i.e. the hard starting when warm, the galloping idle and the occasional stall when restarting from hot have vanished!

I purposely made a number of stops and restarts with several time variations between the stop/start to see if that had any effect but no, consistent every time.  A press of the starter and the sweet purr of the CP3 was back to as I remember it.

So, was it one or more of the tasks completed that 'did the trick'? 🤷‍♂️ TBH - I don't really care!  But as mentioned, if you're having similar symptoms it just might...might be worth looking at the above.

Further to all that, I felt during the ride that the bike was 'smoother' for want of a better description.  Any vibes that were there before felt different and less noticeable.  Acceleration was immediate and power on tap with a twist of the wrist - and I gave it a bit of a wringing on the trip to assist the Ring Free to get rid of any carbon build up . Ya know what I'm sayin.😉

Placebo effect?  I honestly don't think so.

@2and3cylinders - as per your request of KUITL and to you @skipperT as you're now full bottle on what KUITL means 🤣.

Seriously guys, thanks for your help and advice. 

Anyway, enough rabbiting..  HTH

[skipperT]

Great news, Daz and I’m glad to hear she’s back to her old raging self. That’s also a testament to YOU as well, some of the work you’ve just completed is not trivial by any means so congrats brother! Way to go. 

(and thanks for KUITL lol. )

-S