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Discussion Starter #1
I did a search, and found really nothing. 2006 ST3S. I know it's time to bite the bullet and do the valves, belts, F.I tango, but I work in a car port, and it's still cold out there. The last three cold starts, the bike has flooded. I push the start button, the bike does its start up up hokey pokey, then, nothing. Sometimes a cough. Once, I smelled gas. So far, holding the throttle wide open starts it. No problem with hot starts

Fuel pump is working, and the filter is new.

Any stop gap ideas until I can get a couple warm days I don't want to ride?
 

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Strange...the ECU should be on top of this. A thorough tune should take care of your hard starting. I understand about not working in the cold though! Without a full tune, I'd start by looking for air leaks around the throttle bodies. Have the carbon can still? Check those hoses to make sure there are no cracks or any have popped off. You mentioned "car port," any chance a critter has made a nest of your air filter? My buddy had a chipmunk pack his air box chock full of bird seed...must have made a thousand trips to the feeder and back! That's all I got for now.
 

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Sometimes gunk builds up in the throttle bodies on the throttle plates and inside the bore just where the plates sit. The gunk make a nice waxy ridge limiting airflow in an area that already has a very small opening. The same (normal) amount of fuel is pushed by the ECU / injectors. Certainly enriches the mix at idle. This has happened to me a few times over the years (since Ethanol gas oddly enough). I haven't had a no-start condition, but have had low idle and very rich smelling exhaust. Normally a good cleaning fixes it right up. When I think I have this issue, I pull the filter and clean inside the throttle with a rag soaked in carb cleaner as well as I can. Hold the throttle open and wipe in the bore with your finger. You can get the edges of the plates too. May or may not be a contributor in your case, but an easy thing to try.

Of course, if you have to evict a family on small rodents from your air box to do this work, you may have found the issue!
 
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I vote rodents also. The LOVE airboxes. Nothing like a clogged airbox to starve you of air. Hopefully they didn't chew through the filter and get into the "clean" side of the airbox. Then it gets real ugly.
 
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Discussion Starter #5
Will check the air filter again, but it's doubtful. Throttle bodies might need cleaning. I use ethanol free gas. Right now I'm chasing a BMW electrical gremlin. Thanks for the ideas. Could the TPS cause this? GUZZI DIAG appears to have the capability of dealing with the stepper motor. Does anyone know how this works?
 

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Could the TPS cause this? GUZZI DIAG appears to have the capability of dealing with the stepper motor. Does anyone know how this works?
Yes and yes.

Don't mess with the TPS setting until you have your valves adjusted, throttle bodies cleaned, installed a new air filter, and evicted the rodents. You would be changing a parameter that should only be done with a solid baseline. If you adjust this now, and find some other stuff out of whack, you could then make the situation worse.

The TPS reset tells the computer that the current throttle plate opening is at x degrees and dumps the appropriate amount of fuel for this amount of air. The stepper motor does not impact the TPS...when the ECU senses a cold start condition it adjusts the air bypass into the throttle bodies by way of the stepper motor. The motor controls an air valve.
 

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Did you do any work to the bike that might have caused the problem?

TPS: They're not immune to going bad. A friend has a bad one on his ST2, and made for some very weird running, until a good shop finally diagnosed it, and replaced it. As they go "bad", they're sorta like a scratchy volume control on an old radio - you're not getting a clean, precise voltage out of them at a specific setting.
You could verify this with a voltmeter, to make sure that the voltage back into the ECU is very controlled, and proportional to opening the throttle slowly, with no "dead spots".

Rodents also like to chew thru radiator hoses, and wiring. You might want to make sure that the TPS is still plugged in, and the wires are intact.

My ST4s came back from the shop one time after valve adjust. - very hard starting, running totally crappy - turned out that the tech somehow left the TPS unplugged (or knocked it off?). Boy was I sure glad it was that easy !!
It turns out that the bike can run in a "limp-home-mode" even with the TPS not connected ! Runs, but runs like crap!
 

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Discussion Starter #8
Thanks for all the ideas and suggestions. Right now, I have a pretty full plate including a trip to Wyoming for a family matter. No bike. April is blizzard season there.

I rode it a couple days ago, and it started as normal on the second chuff. Weird. It has been two years since belts and valves, so either the local dealer does it while I'm gone or I will do it when I return.

Ever since I had a kickstand fall off after a dealer visit..... They told me it was loose and that they had put Locktite on it. I just hate to take a bike in for something I should be able to do. :frown2:
 
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