Is my TPS giving out?

[outasight20]

2005, 35K miles. Original TPS as far as I know. Recently when riding on the highway and rolling off the throttle, the bike will hesitate as if the throttle was fully shut, even though it is still partially open. Seems to happen only once the bike is fully warmed up. Did self diagnostic on TPS and got 16 closed and 100 open, and very smooth and linear changes between open and closed.

Only happens at very low throttle and I've only noticed it on the highway, but this may be due to increased wind resistance making it more noticeable when the throttle closes.

Recently replaced the spark plugs with NGK Iridiums and did a valve clearance check. All was good. Checked my ignition wires and all are tight. My gut tells me that this is the TPS. What do you guys think? Is it totally free to get it replaced at the dealership?

The bike was sitting in storage for the winter without any fuel additives, but I ran a tank with Seafoam recently to clean out the injectors and the engine is running very well except for this issue.

 

[FinalImpact]

I'm guessing its free only if found to be defective.
Is all of the Seafoam burned off. It may be part of the response issue.

Perhaps a tank of Plus grade fuel and if available, Chevron Techron Injector treatment? The reason I suggest this is some engines seem to stumble under load on Seafoam.

Was the final gap on the new plugs under 0.6–0.7 mm (0.024–0.028 in)?

 

[greg]

I've had my TPS play up a couple of times, after testing it in the diagnostic mode and going from fully closed to open a couple of times (engine off), it seemed to be ok. I've not encountered any issues since, and that was a couple of years ago.

 

[outasight20]

I'm guessing its free only if found to be defective.
Is all of the Seafoam burned off. It may be part of the response issue.

Perhaps a tank of Plus grade fuel and if available, Chevron Techron Injector treatment? The reason I suggest this is some engines seem to stumble under load on Seafoam.

Was the final gap on the new plugs under 0.6–0.7 mm (0.024–0.028 in)?

All of the Seafoam has been burned off as that was several tanks ago. I've read that gapping on the iridiums is not necessary and may actually damage the electrode. As far as I know most people here don't gap them and have no problems. I'll try a tank of Premium fuel with injector treatment and report back.

 

[TownsendsFJR1300]

I've read that gapping on the iridiums is not necessary and may actually damage the electrode.

Iridiums should be checked:

NGK Spark Plugs USA



A NGK video on how to adjust your iridiums:

NGK Spark Plugs USA

Likely NOT your problem but they should be checked for proper adjustment..

 

[FinalImpact]

All of the Seafoam has been burned off as that was several tanks ago. I've read that gapping on the iridiums is not necessary and may actually damage the electrode. As far as I know most people here don't gap them and have no problems. I'll try a tank of Premium fuel with injector treatment and report back.

I'm sorry but the spark plugs gap must be checked as the plug has many other applications (not just this engine) which means the gap MAY NOT BE SUITABLE for this vehicle!
If the gap is too large it can be the cause of the poor acceleration upon re-wetting the intake. So, you might want to check them before taking it in.

As Scott points out, there is a right way and wrong way. Yes, the wrong way could damage the precious metal plug. Using the proper tools for the job reduces the risk of damage.

Bottom line: the plugs must be gapped to meet the requirements of the engine they are installed in.

 

[Motogiro]

Also: Only adjust the gap using the proper tool and adjust the "L" shaped ground electrode in very small amounts. Just don't pry against the center anode.

More...[ame="http://www.youtube.com/watch?v=lk70oyUEftY"]Spark Plug Gap - NGK Spark Plugs - Tech Video - YouTube[/ame]

 

[outasight20]

Quick update.

Yesterday I gapped all the plugs to .635mm. One of them was about .9mm and the rest were .7-.8mm. Went for a ride and still had the same problem, although the bike was running a bit smoother with less vibration.

Then I went to Shell, poured in a bottle of Techron, and filled up with V-Power (I've always used 87 before this).

On my ride to work this morning, the bike got smoother and smoother. No more hesitation! And I can't believe how much of a difference the Techron made!

Thank you for the suggestion FinalImpact! I'll definitely report back in a few weeks and let you guys know if the problem is permanently fixed after going back to 87.

 

[lonesoldier84]

The only way to know for sure would be to fill in a TPS report.

You didn't get the memo?