Skililo

.040 Over
Joined
Aug 20, 2016
Messages
60
Location
GA
Ride
2013 Triumph Rocket III Roadster
I love Rocket III electrical components :mad:

But this is not a rant about that, so here's some experience to share on TPS, then how in the world to navigate through the maze of 'possibilities' while trying to exorcise your motorcycle.

The first thing I had to understand about TPS (throttle position sensor) on my 2013 Roadster was there are not two Stepper motors
- that there are two positions on the TPS that can relate to the Stepper motor action:

The primary throttle stepper motor is used to ensure target idle speed is maintained.
It also increases throttle opening when the engine is cold. What this means to the average jockey sitting on the saddle, is that the bike will start up just fine, you can rev it - you can idle, you can sit there and admire the view with the engine ticking over whilst all is joy.

Till you put the bike in gear :cool:

Then one of two things happens;
- either the bike immediately cuts out
- or (if you double de-clutch) you can pull off, but the bike will cut out 100 yards down the road instead.

If the bike is cold, and not yet reached 72 degrees, you're fine.
Soon as that engine gets hot however, something else takes control of your bike-life.

The second throttle stepper motor, (in response to commands from the ECM) moves the second throttle spindle.The second butterfly optimizes engine torque by maintaining intake air flow speed.

When something is amiss with that TPS, and the engine gets hot - this means you flame out.

You can put the bike in neutral, come to a complete stop - turn the key on and off, then restart, she'll fire up instantly. Shift the motorcycle into gear however, and you're back to the previous paragraph. There is no 'limp-home-mode', there is no permitting you to creep forward under 2000 RPM - engine cuts out and your gauges will display (just as they ordinarily do) when the bike is running. No warning lights, RPM reading, speed indicated - its business as usual when you glance down at the instrument cluster.

There's an important thing to note here too - there will be no DTCs (diagnostic trouble codes) and there will be nothing displaying on the MIL (malfunction indicator lamp) - its not a wiring issue, its at component level.

So time to break out the service laptop and start to do some function tests.


The voltage at the stepper motor is out of range.
The voltage at the TPS fluctuates and does not hold firm.

You can reset those values, clear and default your Adaptive status to purge all the gremlins from the last forty start and warm ups to 72 degrees, (then moving off and coming to a controlled stop). But the problem shall remain if that TPS is faulty. Take it for a test ride and long as that engine is hot - she'll flame out. If the engine is cold, you'll think you have it fixed!

A bad sensor is a bad sensor though and there's only one course of action now open - replace the sensor @$130
 
Last edited:

Rocket3Pilot

Supercharged
Joined
Jul 23, 2015
Messages
475
Location
Waynesboro Virginia
Ride
2013 Rocket III Roadster
I love Rocket III electrical components :mad:

But this is not a rant about that, so here's some experience to share on TPS, then how in the world to navigate through the maze of 'possibilities' while trying to exorcise your motorcycle.

The first thing I had to understand about TPS (throttle position sensor) on my 2013 Roadster was there are not two Stepper motors
- that there are two positions on the TPS that can relate to the Stepper motor action:

The primary throttle stepper motor is used to ensure target idle speed is maintained.
It also increases throttle opening when the engine is cold. What this means to the average jockey sitting on the saddle, is that the bike will start up just fine, you can rev it - you can idle, you can sit there and admire the view with the engine ticking over whilst all is joy.

Till you put the bike in gear :cool:

Then one of two things happens;
- either the bike immediately cuts out
- or (if you double de-clutch) you can pull off, but the bike will cut out 100 yards down the road instead.

If the bike is cold, and not yet reached 72 degrees, you're fine.
Soon as that engine gets hot however, something else takes control of your bike-life.

The second throttle stepper motor, (in response to commands from the ECM) moves the second throttle spindle.The second butterfly optimizes engine torque by maintaining intake air flow speed.

When something is amiss with that TPS, and the engine gets hot - this means you flame out.

You can put the bike in neutral, come to a complete stop - turn the key on and off, then restart, she'll fire up instantly. Shift the motorcycle into gear however, and you're back to the previous paragraph. There is no 'limp-home-mode', there is no permitting you to creep forward under 2000 RPM - engine cuts out and your gauges will display (just as they ordinarily do) when the bike is running. No warning lights, RPM reading, speed indicated - its business as usual when you glance down at the instrument cluster.

There's an important thing to note here too - there will be no DTCs (diagnostic trouble codes) and there will be nothing displaying on the MIL (malfunction indicator lamp) - its not a wiring issue, its at component level.

So time to break out the service laptop and start to do some function tests.


The voltage at the stepper motor is out of range.
The voltage at the TPS fluctuates and does not hold firm.

You can reset those values, clear and default your Adaptive status to purge all the gremlins from the last forty start and warm ups to 72 degrees, (then moving off and coming to a controlled stop). But the problem shall remain if that TPS is faulty. Take it for a test ride and long as that engine is hot - she'll flame out. If the engine is cold, you'll think you have it fixed!

A bad sensor is a bad sensor though and there's only one course of action now open - replace the sensor @$130
Excellent write-up! Thanks, if I ever get those symptoms I'll just replace the TPS. What a dumb design?
 

BigNorm

Boobie Inspector
Joined
Apr 30, 2016
Messages
3,431
Location
Minden, NV, USA
Ride
2014 Rocket 3 Touring
Is there a better replacement for the tps? Or are we doomed to repeat this process again and again? It sounds like a good part to have in the saddle bag.
 

skydog1000

Living Legend
Joined
Jul 13, 2012
Messages
2,333
Location
Oklahoma
Ride
2009 RIII Classic 1980 Yahama XS1100
Is there a better replacement for the tps? Or are we doomed to repeat this process again and again? It sounds like a good part to have in the saddle bag.
A while back I think someone found something at a car parts store that worked and was cheaper. Can not remember who it was though.
 

Roscoe

Biker Chaplain
Joined
Mar 5, 2018
Messages
317
Location
Logan City Queensland
Ride
2008 R3
Few of us over here have had the issue of cutting out or a hanging idle at 3000rpm etc...... guru at Triumph Shop here in Springwood found a fix, yes a faulty TPS but also he disposed of the plug and resoldered all connectors he said the connectors were a part of causing the problem, I now know 3 people who have had the tps and rewire done and no issues now for one bloke was 2 years, myself so far has only been about 10000 klms but see what time tells. Just a thought for yas.
 

Bedifferent

Old man on a bike
Joined
Dec 11, 2014
Messages
1,716
Location
Coldwater, MI
Ride
2015 Rocket 3 Touring
So is it the secondary sensor towards the rear or the primary towards the front that is most problematic?Or both?
 
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