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Discussion Starter #1
Ok folks...I've got a problem. I have a 2005 Polaris 800 efi I've been riding. Fuel pump failed a few months ago so I replaced it and all was fine. Now the idle is really bad and top end is nonexistent. Started out of nowhere and was running top notch until this happened. I did some research and downloaded a service manual for it. I checked the tps voltage and it was all out of whack. So I probed everything and adjusted to the service manual specs. And it will not run at those specs. I didnt change out the fuel pressure regulator in the tank but that'll be my next step seeing as how it looks like theres a LOT of fuel being sent back in to the tank. Does anyone have any idea on another voltage setting to try? Any idea as to why the manual specs dont work? I was told to talk to AKStew about all this. Maybe he will answer. Thanks in advance...
 

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If you have about 38 psi +/- 2 at the fuel rail there's nothing wrong with fuel delivery.
Did you clean the throttle body good before messing with the TPS settings?
Have you moved the throttle stop screw?
Your TPS base voltage should be set at .528 with a spotless clean TB and the cable unhooked. Lock down the TPS at that base voltage and then crank the throttle stop screw up to .710 Once you are sure you have it right apply a drop of thread locker or fingernail polish to the screw to prevent it vibrating out of position.
At each setting sweep the throttle through its full range of motion a few times to make sure it returns to the correct setting before moving on to the next step.
 

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Discussion Starter #3
If you have about 38 psi +/- 2 at the fuel rail there's nothing wrong with fuel delivery.
Did you clean the throttle body good before messing with the TPS settings?
Have you moved the throttle stop screw?
Your TPS base voltage should be set at .528 with a spotless clean TB and the cable unhooked. Lock down the TPS at that base voltage and then crank the throttle stop screw up to .710 Once you are sure you have it right apply a drop of thread locker or fingernail polish to the screw to prevent it vibrating out of position.
At each setting sweep the throttle through its full range of motion a few times to make sure it returns to the correct setting before moving on to the next step.
All that I did...that's what makes no sense. I did everything exactly like you just said...three times in fact to make sure I didn't miss a step. But it will not even start at those settings.
 

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I'd say you got something else going on if it won't even start at factory spec settings. I've seen a few that needed a little tweaking from spec to run really well but not that far off. Make sure you have the correct reference voltage of 5 vdc to the tps harness before trying to set it. Check the harnesses to the TBAP, crank sensor and tps too.
 

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Discussion Starter #6
I'd say you got something else going on if it won't even start at factory spec settings. I've seen a few that needed a little tweaking from spec to run really well but not that far off. Make sure you have the correct reference voltage of 5 vdc to the tps harness before trying to set it. Check the harnesses to the TBAP, crank sensor and tps too.
I'm back probing the yellow wire. I believe that to be the hot wire.
 

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Discussion Starter #7
Ok folks...I'm officially out of ideas. I checked all my harnesses and no bad wires or anything. So I pulled the throttle body off and cleaned it well. Reset the tps voltage to .528 but when I went through the throttle range it would change every time. Example...528 at start...went through throttle motion and it would come back at 580 then 527 etc. Worked on it until I got it to stay close as I could to .528. Then I adjusted the butterfly until it hit .710. Same thing...went through the throttle range and it would change everytime. So I adjusted as close to .710 as I could. It would try to start but wouldn't idle. So I tweaked the tps until it started and idling at 1200 rpm. Voltage at tps now shows 1.220 volts. Took it for a spin and it topped out at 35 mph and almost got stuck in a small mud hole. Also now I can smell fuel from the airbox. Where do I go from here? Is the tps bad and is that the reason the voltage changes? Thanks in advance for any help.
 

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The dealer has software, a computer and the diagnostic link to check the electronics of the vehicle - try taking it to a well equipped and trained mechanic to be satisfactorily repaired - if you don't want to pay the price, sell it and get something with a carburetor.
 
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