Erratic Idle and Stall Issue Help?

madcapmoto

Standard Bore
Joined
Apr 25, 2024
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5
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2014 R3 Roadster
I've lurked for a bit and cannot find my exact issue. Particularly after a lengthy ride the tach seems to stumble and continue to dip lower then level out, and at it's worst completely stalls out after a higher rpm rev.

I've had in two separate dealerships a total of three times in the last year with no help other than emptying my pocketbook. Once I paid a diagnostic fee to be told it was in my head and they could not recreate the issue. I took it back after reading the issues with the TPS and had them replace both the primary and secondary sensors which did seem to make the bike run better for about 6 months but never quite great. 6 months after the TPS replacements I took it to dealership #2 who were confident it was an air issue, and suggested I replaced my RAMAIR filter. I ended up replacing the filter, the extension cable for the intake air sensor, and the intake air sensor itself. The tech said he balanced the throttle bodies and although the issue was not fixed he was confident the air filter would address it. The issue persists. I'm attaching a video of a force stall in hopes someone has seen something similar. Appreciate any input I can get.

 
The primary TPS is usually the culprit. But as you have already replaced it, that's strange. Was it set to the correct setting when installed? Also spraying the throttle linkage with lubricant/cleaner may help.
I assumed it was properly set at the dealership when installed but a few interactions with that dealership does leave me skeptical
 
Could you tell us how it runs at cruising speed? Any stumbling? What about when you're accelerating quickly, does it stumble or miss? The reason I ask is that the video shows the stumble taking place when the throttle comes to an idle which would indicate the stepper motor isn't picking the idle up quickly. The stepper motor is out of the circuit off idle. If acceleration and cruising appears normal, I'd check the stepper motor and reconfirm the primary TPS was adjusted correctly. The stepper motor can hang up a bit if things get a bit dirty. This is usually corrected by spraying penetrating fluid under the rubber boot on the motor. You might want to check for a vacuum leak also. This usually affects the idle circuit more than anything. No problems with cruising and full throttle pretty well point to the idle circuit and vacuum leak issue. Also, check to see if the primary wire connectors (2 per coil) are tight. These do come loose causing a miss at times.

As to your 2nd dealer blaming the RamAir then removing it, (and I assume converting back to original) I wouldn't go back. Obviously their mechanic has no experience.
 
Could you tell us how it runs at cruising speed? Any stumbling? What about when you're accelerating quickly, does it stumble or miss? The reason I ask is that the video shows the stumble taking place when the throttle comes to an idle which would indicate the stepper motor isn't picking the idle up quickly. The stepper motor is out of the circuit off idle. If acceleration and cruising appears normal, I'd check the stepper motor and reconfirm the primary TPS was adjusted correctly. The stepper motor can hang up a bit if things get a bit dirty. This is usually corrected by spraying penetrating fluid under the rubber boot on the motor. You might want to check for a vacuum leak also. This usually affects the idle circuit more than anything. No problems with cruising and full throttle pretty well point to the idle circuit and vacuum leak issue. Also, check to see if the primary wire connectors (2 per coil) are tight. These do come loose causing a miss at times.

As to your 2nd dealer blaming the RamAir then removing it, (and I assume converting back to original) I wouldn't go back. Obviously their mechanic has no experience.
 
At cruising speed it seems fine. The engine braking is a little clunky but nothing alarming. The tech didn't suggest converting to stock as far as the ramair but replacing the filter unit itself due to "slight cracks in the rubber" as he called them. I replaced it direct from ramair and ordered the intake air sensor cable at the same time, and just to be sure ordered the actual air sensor itself from Triumph. I appreciate the leads and I'll go back down that path and see what shakes out.
 
The slight cracks in the rubber mount boots were an issue with RamAir several years ago. A few members from this site actually complained to RamAir and had them replaced under warranty. Good company.

I found this previous thread on removing the stepper motor Stepper motor removal . Interesting read. The individual had a similar problem to you and eventually removed it. This corrected the symptoms. If you do this, you will have no fast idle on startup. You would have to hold the throttle a bit.
 
Your description of symptoms is a little vague. Earlier in its life, my '05 when pulling up to a corner, would idle really slow, then go back up to normal idle speed. Sometimes it would stall before it recovered. The cure for mine was adjusting the yellow painted idle hard stop screw. It's located on the end of the throttle body where the throttle cables attach. Turn it in a little bit at a time until the problem is resolved.
 
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