High Idle On 2017 Thruxton

On first start from cold, RPM goes straight to 3,000 RPM and stays there for a long time. When fully warmed up, idle drops to 1,400 RPM. Should be about 1,000 RPM. When bike was new, cold start RPM would be 2,000 RPM, then 1,000 RPM after warm up. This has been going on for about 3 months. I recently balanced my throttlbodies using Dealertool. I read that the throttle is supposed to have about 4 MM of free-play before rising above idle. My throttle grip has no free-play. When I push the grip hard against the stop, the idle lowers to 1,000 RPM. When I let go, it rises back up to 1,400 RPM. Is there any adjustment I can make to the throttle grip to achieve proper idle RPM? This is throttle by wire, so no mechanical cables, idle screws, or anything else to adjust. Dealertool will not change the ECU, so that option is off of the table. Al Dealertool will do is tell you what idle you are running at, and what RPM it should be. Any and all hep is appreciated. Thanks.

 

Is the throttle postion sensor TPS in the handgrip, or down near the throttle bodies?

 

My bike is throttle by wire. The ECU takes care of all the choke/enrichener functions of cold start. There are no knobs or set screws to adjust for cold start functions. I think if it was an earlier model, this would be something to look at. I tend to think its either an issue in the hand grip itself, or an ECU reprogramming issue.

 

I took the throttle apart. The white ring inside that the hand grip engages seems to be fine looking at the exterior of it. With the TPS ring sitting disconnected from the handgrip on the handlebar, I started the bike from cold. The RPM immediately went to 3,000 RPM. Eventually it dropped to about 1,400 RPM after it warmed up. I used a screwdriver to force the ring further back towards return. The RPM dropped to 1,000 RPM. When I let it go, the RPM rose back to 1,400 RPM. So I think that part is bad. There is no adjustment to it. I am having a hard time finding it online. I guess I will call the local Triumph dealership on Tuesday when they open back up to see about getting a replacement. It that fixes it, I will tear the old one apart to see why it was acting up.

 

The item Brown Mouse described is what I have. I have discovered that it is not known as a TPS (throttle position sensor), but is actually known as an APS (Accelerator Position Sensor). I can see the springs inside the white plastic housing. There is also white grease (Lithium grease I believe) packed into the springs. I am working with my local dealer on getting a replacement part. Once I get and test it, I will post on this board what the results are. If the new part fixes the issue, I will tear the old part apart and see if I can see any evidence of shorting or any other defect.

 

Okay, here is what I know so far. I was able to download a shop manual, and used it with my DealerTool. Using the manual, I Ohmed out all the wires from the ECM to the throttle handgrip. Everything checked out good. THe EMP and the Throttle Position Sensor are non-adjustable on this bike. I did replace the twist grip position sensor with a new one. No change, still idling high cold and hot. Here are some numbers I got at the high idle I am currently experiencing:
TWIST GRIP:
#1 -1.29V
#2 - 1.57V

MAP SENSOR
#1 - 2.0V
#2 - 0.0V

TPS
#1 - 0.71V
#2 -1.57V

O2 SENSOR
#1 - 0.88
#2 - 0.06

I think I'm going to next dive into the headlight shell as a lot of the wiring for the bike goes through there. Maybe there is a wire or connector that is not seated or routed correctly. Is there anyone out there that has a similar bike to mine that can share what they are reading on their DealerTool when the bike is at idle. I'd like to know what kind of voltages they are reading on all of the different sensors that are monitored. Thanks a lot.

 

I was able to download the shop manual. I went through the entire throttle and throttle control system. Everything checked good to include all the wiring going from the throttle to the ECM, and from the ECM to the TPS on the side of the throttle bodies. I finally was able to take it to the local dealer. We agreed that either the TPS has an internal fault and will need to be replaced, or teh ECM has a programming fault and will need to be reflashed, It turned out to be the ECM. The ECM was reflashed to factory spec, and everything went back to normal. I am not able to reflash the ECM using DealerTool, so I am thinking that I may move on to getting Tune ECU in the future if this issue ever arises again.

 

I think the whole issue started because of a defective oxygen sensor. To take care of that issue, I replaced the oxygen sensors with an oxygen sensor delete kit that included the block-off plugs and resistor plugs. Then I installed a Motone X-pipe to go along with the Vance & Hines mufflers with baffles removed that I installed last year. I have to say that I really love the sound from the exhaust, and the very noticeable increase of power and response from starting out from a stop, and also when rolling on power at speed. This is now the bike with the performance, speed, looks, and handling that I've always dreamed of.