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500EXC Sputtering and stalling help

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I recently bought a 14' 500EXC with 32 hours on it. It has has a full FMF pipe with the power bomb header. It has an FMF Snap. I set the TPS to .63 and it runs great EXCEPT for a sputtering issue at low RPMs when under a load, like I'm taking off from a stop slowly. Or today I was giving my 23 month old son a ride and when I was going slow it would occasionally sputter and almost die. It almost seems like it is running out of gas for a split second. Also if it is idling and I'm stopped on a downhill it will sometimes randomly die. (It was worse, stalling a lot more frequently in corners or when I was starting out, but I increased the TPS from .59 to .63 and it got better)

 

Any help would be greatly appreciated. Thanks!

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Increase the TPS a bit more and see if it helps further.  Also check to see if the solenoid under the throttle body is still there.  It's a little box with wires under the throttle body, with 2 hoses, one of which goes to the intake manifold.  If it's still there, unplug the wires from it and see if that also helps.  I know exactly what you're talking about, it happens just as you crack the throttle and it acts almost like you actually closed the throttle a tad.  My 2014 500exc had exactly the same stumble just as you crack the throttle, but removing the smog parts (including that solenoid) and adjusting the TPS 100% resolved it on my bike.  

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Increase the TPS a bit more and see if it helps further.  Also check to see if the solenoid under the throttle body is still there.  It's a little box with wires under the throttle body, with 2 hoses, one of which goes to the intake manifold.  If it's still there, unplug the wires from it and see if that also helps.  I know exactly what you're talking about, it happens just as you crack the throttle and it acts almost like you actually closed the throttle a tad.  My 2014 500exc had exactly the same stumble just as you crack the throttle, but removing the smog parts (including that solenoid) and adjusting the TPS 100% resolved it on my bike.  

Ok. I'll try that. Is there an acceptable range for the TPS? Should it be of concerns if it is above or below that range? Also, the guys I bought it from removed the smog stuff and I don't know what it looks like. Could you send me a pic of where I should be looking for it.

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Increase the TPS a bit more and see if it helps further.  Also check to see if the solenoid under the throttle body is still there.  It's a little box with wires under the throttle body, with 2 hoses, one of which goes to the intake manifold.  If it's still there, unplug the wires from it and see if that also helps.  I know exactly what you're talking about, it happens just as you crack the throttle and it acts almost like you actually closed the throttle a tad.  My 2014 500exc had exactly the same stumble just as you crack the throttle, but removing the smog parts (including that solenoid) and adjusting the TPS 100% resolved it on my bike.  

Sorry, by it I mean the solenoid.

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Mine is removed so I can't send a picture, but look under the throttle body and see if there is a solenoid mounted there.  It's big and obvious.  If there's nothing mounted to the bottom of the throttle body then you're fine.  

It will start running bad if you get the TPS too high.  Some guys have been up in the 0.7v range and happy, but most end up around 0.64.  You're still down at 0.63 so I  think you can safely increase a little more and test. 

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did you check the battery connections.....?

No, but it has a lithium battery and everything else works great. Wouldn't hurt to check it though. Thanks for the tip.

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Mine is removed so I can't send a picture, but look under the throttle body and see if there is a solenoid mounted there.  It's big and obvious.  If there's nothing mounted to the bottom of the throttle body then you're fine.  
It will start running bad if you get the TPS too high.  Some guys have been up in the 0.7v range and happy, but most end up around 0.64.  You're still down at 0.63 so I  think you can safely increase a little more and test. 

I just looked at my buddy's 500 that hasn't had the smog stuff removed and saw what you were talking about and it has been removed on my bike. I'll try increasing the TPS to see if that helps. Thanks for the advice.

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On ‎4‎/‎12‎/‎2017 at 2:23 PM, shine13 said:


No, but it has a lithium battery and everything else works great. Wouldn't hurt to check it though. Thanks for the tip.

type of batt isn't the issue its the ground strap from the negative side of battery gets loose

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Mine was loose at the battery when I got my '17 500 exc-I assume the battery was installed by the dealer?

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