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Discussion Starter #1
Okay so it would appear that this is not an uncommon issue but I'd like to know how I should go about resolving this without dropping 4-500 on a new throttle body.

I just bought this machine with 750 miles and 60 hours on it. Since I got it, when I am slowly on/off the throttle, it will stay there when I release the pedal, almost at a high idle RPM. I have to blip the throttle to make the butterfly valve fully go back to idle, and its kinda dangerous when trying to go slow.

I pulled the throttle body and cleaned the buttery fly valve, I also used contact cleaner on the MAF, ISC valve, and the TPS. Nothing changed.

I FULLY inspected the mechanical functions of the unit and throttle cable and it works just fine, the spring for the butterfly valve quickly and strongly closed the flapper, and the cable operates smooth as ever. So I am thinking this is electronic in nature. When the machine is off, the valve snaps close without issue, IT ONLY STICKS OPEN TOO MUCH WHEN THE MACHINE IS RUNNING, which also leads me to thinking it's a sensor problem.

I did and EFI reset, I also used the diag menu to see that the TPS is working accurately, it does show that it sees the throttle sticking anywhere from 2-4%, and shows it going back to 0% when I blip the throttle and idle is normal.

Where do I go from here? The handful of posts I read mention mainly mechanical failure of the throttle body spring as a common issue, but here they seem to work just fine, it appears whatever part/sensor that is responsible for holding the butterfly open at idle, is responsible for not letting it go back to idle when the throttle is let off, so what should I do?
 

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Idle air is adjusted by the large round device mounted on the throttle body. It bleeds air through a path completely separate from the butterfly. The butterfly is not managed by anything other than the cable, spring and throttle stop. That 2 to 4% reading suggests it is still hanging open.

There is more than enough cable travel to fully open the butterfly. I always adjusted mine to have a bit of slack when the throttle is closed.
 

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Discussion Starter #3
Idle air is adjusted by the large round device mounted on the throttle body. It bleeds air through a path completely separate from the butterfly. The butterfly is not managed by anything other than the cable, spring and throttle stop. That 2 to 4% reading suggests it is still hanging open.

There is more than enough cable travel to fully open the butterfly. I always adjusted mine to have a bit of slack when the throttle is closed.
Thanks, so when idling, the butterfly is supposed to be completely closed and nothing electronically positions it, which means maybe I need to re-assess the little hang up just before closing and what mechanical failure is causing it, or I guess just deal with it?

Like I said, it seems any of the posts I read through, people either had an obvious issue mechanically, OR the dealer just said, "oh we need to replace the throttle body," and magically all problems were solved.
 

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Discussion Starter #4
Okay, since this assessment does not seem to be posted anywhere on the internet, I am going to post what I believe is my novice mechanical evaluation of the sticking open throttle body problem:

The throttle body flap ONLY STICKS a bit open when the vehicle is running, and opens anywhere from 2%-4% (based on the TPS diagnostic reading). My throttle cable is completely smooth and not sticking or binding, it is FULLY adjusted with slack let out of the cable, (in other words, the adjustment nuts are not taking any slack out of the cable so the flapper should be able to completely shut). I have no codes

I believe it makes sense that the spring in the the throttle body (TB) is just simply weak, which is pretty much what most people have said unless there is another explainable mechanical failure or blockage. The spring inside the TB has to overcome the friction of the throttle cable sliding back when the the gas pedal is released, and when the vehicle is running, it has to overcome the pressure of air being pulled in through the throttle body.

That final bit is important, as what I’m thinking is the force of air being pulled through the throttle body in combination with the engine vibrations cause air to leak past the flapper when you slowly open/close the throttle. Basically the spring does not have enough momentum to “slap” the flapper valve close when you close it slowly.

I will post my own video as well as another I found on YouTube of this condition. There does not seem to be a replacement spring you can purchase, it’s part of the throttle body and it must be replaced with the whole TB. Whose to say purchasing a replacement wouldn’t just end in the same result as well? A replacement is $500.

So with that, I’m going to try to clean and lube the flapper pivot, and put it all back together and just deal with the sticking, it’s dangerous especially when operating in tight spaces like parking or when loading/unloading, but as of now I don’t see a way to repair this without spending a lot. If anyone has any further info, please let me know.


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Interesting thought, but the air flowing through the throttle body pushes evenly against the top half and lower half of the butterfly. One half pushes it open, one half pushes it closed.

I didn't understand what you were trying to communicate about slack in the cable. There should be a bit of slack in the inner cable where it attaches to the throttle shaft.

This might not be at all practical, but if you can manipulate the throttle shaft without the cable installed, start it up and open the throttle manually to see if it still sticks.

When I was selling my spare, I found that all of the old Wildcats (1000, X, Trail, Sport) use the same throttle body. You might find a deal on a used one.
 

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Discussion Starter #6
Interesting thought, but the air flowing through the throttle body pushes evenly against the top half and lower half of the butterfly. One half pushes it open, one half pushes it closed.

I didn't understand what you were trying to communicate about slack in the cable. There should be a bit of slack in the inner cable where it attaches to the throttle shaft.

This might not be at all practical, but if you can manipulate the throttle shaft without the cable installed, start it up and open the throttle manually to see if it still sticks.

When I was selling my spare, I found that all of the old Wildcats (1000, X, Trail, Sport) use the same throttle body. You might find a deal on a used one.
That makes sense, I hadn’t thought about it evenly pressing against the valve.

What I meant by the adjuster nuts, was that right where the throttle cables goes into the the throttle body there is a nut/lock nut, and I completely loosened them while testing so that the cable slack was left and not taught. Because being taught would be pulling the cable out from the throttle body potentially holding the flapper open if adjusted too tight.

Either way, I looked online and just purchased the throttle body from a 2015 Wildcat X for $120.....I figure that’s worth a shot. Parts fiches show it’s the same part #.


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Discussion Starter #7
Okay! So bad news, I received the TB from a 2015 Wildcat for $125, and unfortunately, absolutely no improved result. So crazy.

Still the throttle plate does not return to completely closed when I release the gas pedal (unless I blip the throttle hard or let the throttle close fast).

This results in strange idle behavior and the throttle slightly sticking like it has been.

This also results in a strange behavior where the TB is opened just so incredibly slightly, that the TPS might read 0, but air is still getting around the throttle body flapper and this causes the idle control sensor to be confused and causes erratic idling and an engine stall.

At this point I have absolutely no clue what to do. And I guess I’ll try to return the throttle body I bought, and install the old one and deal with this odd condition. If anyone reads this and has an idea, let me know.


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There is an adjustment, and a screw that locks the adjustment, for the closed throttle butterfly position. Take a look at your spare throttle body and you'll find it. I don't think this is your issue, as it just establishes the closed position and can't make the throttle stick, but it is something you can try.

I really think you should do what I recommended in the middle of post #5. Run the engine without the throttle cable attached and see if you can re-create the sticking throttle condition. My hunch is that you will not, meaning the issue is in your 8 to 9 year old throttle cable.
 
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