Gen 3 Won’t Fire After Synch Correction

[2DFlier]

Hey all.  
  A little help please.  I screwed up a couple of weeks ago and adjusted #1 (painted) air bypass screw about 1/8 turn when syncing.  It seemed to run fine during synch and started and ran fine the next time it started.  However the next time it started (later that day) it didn’t want to idle cold but was okay when it warmed up.  I realized my mistake soon after. 
   Yesterday I fired it up after some maintenance and it idled rough so I decided to return #1 screw to its position before synch and try again.  After doing so I attempted to start it.  It caught briefly then died.  Now all it will do is crank.  
  The start / initialization sequence seems to be fine.  The fuel pump runs and stops as usual.  I disconnected the fuel line to confirm fuel is present.  The tank is 3/4 full.  I’ve tried starting with the tank propped up and in its normal position.  I disconnected the battery briefly thinking that might help but no luck.
  I can’t imagine that turning the bypass screw 1/8 turn to its original position would cause this problem but, besides stuff related to propping up the tank, the screw is the only thing I touched.

Any ideas?
Thanks,
Allan

 

[RossKean]

What maintenance were you doing before the no start?  How long did you let it run before shutting it off to readjust the TBS?   I am guessing that the current problem is either due to the "maintenance " you performed or you shut it down before it was up to full operating temperature.  If the latter, you may have a flooded condition and it will be a bitch to start.  You need to start out with a fully charged battery in good condition and start the engine with the throttle held fully open. Crank 20 to 30 seconds or so and give it a rest for a few minutes for the starter to cool down (unless it seems to be close to starting).  It might take several attempts but this generally works if the problem is due to too much fuel in the cylinders.  Remember, wide open throttle.

Note: If the maintenance involved anything under the tank - plugs, other wiring etc., check that stuff first.  Make sure the caps are back on the sync ports and no hoses are disconnected. Ensure that the boots are firmly pushed onto the plugs.  I am sure somebody will have other suggestions as well but these seem most likely to me.  Good place to start anyway.

Good luck.

 

[2DFlier]

Thanks much for your response.  The maintenance didn’t involve the tank.  I’d just finished a swing arm lube before starting the bike yesterday.  It only ran long enough to confirm it was running rough.

I didn’t start it today before adjusting #1 bypass.  I figured I’d put the screw back in its original position before starting.  So all I did was reset the screw and attempted to start.

 I’m beginning to wonder if adjusting it before starting is the problem.  It started fine yesterday but idled rough.  Today it caught briefly then died.  The only intentional difference between shutting it down yesterday and starting today was the bypass screw setting.

  I wonder if the ECU detected a difference at startup on the reference cylinder and locked out the ignition or fuel injection.  Had I started it first and then adjusted it I wonder if it might have been okay.

 

[RossKean]

I wonder if the ECU detected a difference at startup on the reference cylinder and locked out the ignition or fuel injection.  Had I started it first and then adjusted it I wonder if it might have been okay.

ECU isn't that smart and ability to start is not THAT dependent upon the state of the TBS.

I think it is flooded at this point although you should make sure all of the sync screw caps are in place and no hoses etc. are disconnected.  Electrical stuff as I mentioned as well,.

 

[2DFlier]

Okay.  Thanks much.  I didn’t think it would be that sensitive to TBS. There also aren’t any fault codes or warning lights.  I checked the caps and connectors.  It’s been sitting for a few hours now so I’ll go out and try to start again.  If flooded it hopefully will be easier to start now.

 

[2DFlier]

I’ll be.... I did as you suggested and it started after about 10 seconds.  Many thanks!

 

[RossKean]

Thought that might be the situation.  Is it idling OK or do you still have the rough cold idle?

Remember to ALWAYS bring the bike up to full operating temperature before shutting it down.  Otherwise, the flooding situation you encountered is much more likely.

 

[2DFlier]

With the screw in its original position fast idle seemed fine last night and settled in at 1100 RPM when warmed up.  I plan to recheck the synch later.  If like it was before screwing it up, I expect #2, 3, and 4 will be 10 ish mm higher than #1.  I’ve  never experienced flooding with an injected engine before so will keep warm up in mind from now on.  Thanks again.  I don’t have a lot of hair left to pull out...

 

[Boston]

My thought is that when cold a leaking injector will flood a cylinder. Time to get a injector cleaning. 

RC in cali does a good job. I sent them mine and two were leaking. They only had 28k miles.

You can screw all the sync screws in. and the lowest vacuum,  adjust the rest to it.  The painted one from the factory is the one with the lowest vacuum.

This is the way I understand it.

John

 

[RossKean]

Difficulty in restarting after an incomplete warmup is a very well documented issue with FJRs.  Conventional thought is that it is due to flooding and the WOT starting method usually gets it going.  Since it is usually only an issue with the incomplete warmup, I doubt the primary cause is a leaky injector although I suppose it could be a contributing factor. 

 

[roger dodger]

Search 'Fast Starter Syndrome' as many of us have had it.   Usually it seemed to show up on older bikes,  so this proves age doesn't matter.   YMMV