Replaced Throttle Position Sensor - Yamaha FJR Forum : Yamaha FJR Owners Forums
 7Likes
  • 3 Post By Myotis
  • 4 Post By red
 
LinkBack Thread Tools
post #1 of 8 (permalink) Old 09-06-2020, 06:30 PM Thread Starter
Junior Member
Training wheels fitted!
 
Join Date: Apr 2017
Location: Cambria, CA
Posts: 8
Replaced Throttle Position Sensor

I replaced the throttle position sensor on my bike, with about 66K miles. Iíve had the bike over three years, and noticed the idle was always a bit rough despite new plugs and repeated throttle body synchronizations. I did the Ivan flash at end of July and had mixed results: at times it was great, but the idle would fluctuate between normal and 2500 RPM, and at times it ran worse than before the flash (yes, I did reset the CO settings to zero, did another sync, and replaced the air filter).

I could not set the TPS sensor to 0.69 volts at idle, it would not hold a constant value when adjusting, and either made the engine race at lower values or nearly stall when closer to 0.69v. I checked the TPS settings on the diagnostic screen and it fell within the normal ranges mentioned on this site, with no gaps or abrupt jumps when turning the throttle from idle to full power.

So I thought this was enough evidence to order a new TPS. I tried checking the resistance as described in the Yamaha manual but could not replicate the test with either the new or old TPS. The manual says to remove the sensor and check resistance between the two outermost prongs, which should be in the range of 4-6 K ohms. On both the new and old TPS, resistance between the outer prongs read infinity. But between one outer and the center prong it read 18 ohms (not 18K since my meter was on the 0-200 range scale), and center to the other outer prong was infinity. The old TPS also only read on the same prongs, but started at infinity unless I rotated the TPS input and then the values would jump all over inconsistently.

I then went for a ride on a nearby canyon road and found vast improvement, better than itís ever been. Much-reduced jerkiness when rolling on throttle mid-curve in second gear and rolling off before the next curve, and full-on smooth but roaring power in the straights. Wow, thatís what I was hoping for with Ivanís flash!

Daniel
2007 FJR1300A
Myotis is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 09-06-2020, 06:40 PM
Senior Member
High-G FJR Junkie!
 
RaYzerman's Avatar
 
Join Date: Jan 2013
Location: Millgrove, ON, CA
Posts: 6,912
Makes sense to me. Very difficult to diagnose a failing TPS. 66k sounds about time.

Ray
Keep yer stick on the ice....
2014 FJR1300A - Root Beer (sold)
2009 CBF1000A - Sienna Red
1999 VFR800Fi - Pearl Shining Yellow
RaYzerman is offline  
post #3 of 8 (permalink) Old 09-06-2020, 09:27 PM
red
Senior Member
FJR Top Gun
 
red's Avatar
 
Join Date: Jul 2013
Location: near Great Salt Lake, Utah, USA, Sol III
Posts: 1,416
Replaced Throttle Position Sensor

Quote:
Originally Posted by Myotis View Post
I replaced the throttle position sensor on my bike, with about 66K miles. I’ve had the bike over three years, and noticed the idle was always a bit rough despite new plugs and repeated throttle body synchronizations.
On both the new and old TPS, resistance between the outer prongs read infinity. But between one outer and the center prong it read 18 ohms (not 18K since my meter was on the 0-200 range scale), and center to the other outer prong was infinity. The old TPS also only read on the same prongs, but started at infinity unless I rotated the TPS input and then the values would jump all over inconsistently.
Myotis,

Glad to hear that you fixed the problem. Good catch.

Apologies if this is too late to help you, but for others then: For many digital multimeters (and the OBD), readings for the TPS may not tell you there is a problem, especially if the problem is not too extreme. However, they do make DMMs with a bar-graph in the digital display. It is a line that travels across the display, according to the value being measured. Such a DMM will still show the digital readings, of course, but the bar graph will tell you if the measurement (the throttle response, here) is being jumpy, intermittent, or smooth (as it should be for a TPS). A purely digital readout will not look bad, there, unless the jumps in the readout are huge or blatant. Old-timers like me may compare the bar graph readout to a swinging-needle gauge, but the bar graph is much more responsive (faster) than any moving needle could be.

As one example, you may discover that a voltage line feeding some balky gadget is actually intermittent, shutting off the power for split seconds at a time, when lesser DMMs would not see the failure. The same applies to the other readings with the DMM as well.

You might not decide to retire your present DMM to simpler duties in favor of a DMM with a bar graph in the display right now. Still, I would recommend that any DMM you buy in the future should include the bar graph readout in the digital display screen. Lately even the less expensive DMMs can have the bar graph readout.

You have to log in over there, but some bar graph DMM pix:

https://www.fjriders.com/forums/view...0c3ddc#p125440

My US$.02 worth. All IMHO, of course.
.

Cheers,
Red
2008 FJR1300A
- Pirelli Angel GT (Spec A) tires, RDL seat, TPMS, GPS digital speedometer (Amazon ~US$28.00).
P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.

Last edited by red; 09-07-2020 at 05:24 PM.
red is offline  
 
post #4 of 8 (permalink) Old 09-07-2020, 09:50 PM Thread Starter
Junior Member
Training wheels fitted!
 
Join Date: Apr 2017
Location: Cambria, CA
Posts: 8
Thanks Red, I'll look into that. I've been thinking of a getting more-capable digital multi-meter to replace my low-end cheapie.

Daniel
2007 FJR1300A
Myotis is offline  
post #5 of 8 (permalink) Old 09-08-2020, 07:21 AM
Senior Member
High-G FJR Junkie!
 
Bill Lumberg's Avatar
 
Join Date: Nov 2014
Location: Southeast
Posts: 2,838
TPS failure, while not common (and replacement isn’t PM), doesn’t result in general fueling issues or general roughness. It normally manifests as a hiccup or infintessimaly small dead spot at a precise and consistent spot in the throttle range. This initially almost imperceptible dead spot will gradually worsen until the bike is almost unrideable. If you’ve got it, you’ll know.


Onboard diagnostics on mine didn’t reveal any problem. But it was the tps for sure.

No commercials. No dictators.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


2018 FJR1300ES Stealth Model

IBA# 69560
Bill Lumberg is offline  
post #6 of 8 (permalink) Old 09-08-2020, 11:49 AM
Senior Member
High-G FJR Junkie!
 
RaYzerman's Avatar
 
Join Date: Jan 2013
Location: Millgrove, ON, CA
Posts: 6,912
Agree, Bill, TPS problems are hard to diagnose, can test good and not be..... basically, eliminate all potential causes of running issues first and replace it as a last resort. The DVM red suggests is a good idea so you can see resolution in your readings..... adding one to the arsenal, shoulda done it years ago.

Ray
Keep yer stick on the ice....
2014 FJR1300A - Root Beer (sold)
2009 CBF1000A - Sienna Red
1999 VFR800Fi - Pearl Shining Yellow
RaYzerman is offline  
post #7 of 8 (permalink) Old 09-13-2020, 09:48 PM
Junior Member
Training wheels fitted!
 
Join Date: Aug 2020
Posts: 10
O-scope

I have a Fluke O-scope. I think this Would this show things more properly than DMM
jasonm. is online now  
post #8 of 8 (permalink) Old 09-14-2020, 12:09 AM
red
Senior Member
FJR Top Gun
 
red's Avatar
 
Join Date: Jul 2013
Location: near Great Salt Lake, Utah, USA, Sol III
Posts: 1,416
Replaced Throttle Position Sensor

Quote:
Originally Posted by jasonm. View Post
I have a Fluke O-scope. I think this Would this show things more properly than DMM
Jasonm,

I would expect that, also. What does your O-scope tell you is happening, when you compare a good TPS against a bad one?

You may need to "simulate" engine vibration by gently tapping on the unit being tested, as you check it.
.

Cheers,
Red
2008 FJR1300A
- Pirelli Angel GT (Spec A) tires, RDL seat, TPMS, GPS digital speedometer (Amazon ~US$28.00).
P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.
red is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Yamaha FJR Forum : Yamaha FJR Owners Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome