Yes it is me again....My 800 has been running rough lately. It always starts no problem, but the engine has just been bumpy with the rpms intermittently

I have cleaned the TB, drained old gas, and added sea foam. I took it out this weekend and it would intermittenly go from bogging down in high gear to all of the sudden running great (huge power surge) then bogging down again.

Two things I noticed. One, is the clear tube running up the neck between the gas tank and the headlight assembly....looks like some sort of gas overflow line or something... looked like fluid was bubbling upward toward the handle bars. This would happen even if the unit was turn off but still hot.

Second thing I noticed, if I did get going good and came to a stop, the engine would die. Would start back up no problem.

Like I said it could be kind of scary going from no power to full power. Any ideas?

 

those are vent lines that need to be free from pinching or plugged. did you try to losen or take off the gas cap when it was runing rough to see if it helped? if it was a vent issue being restricked it might act as you have mentioned. i'm assuming there has been no codes flashing as well? injector cleaner didnt work as well as the new gas. by any chance is it wet when it runs that way, maybe a bad spark plug cap or bad connections on thre harness or grounds. just thoughing some ideas out.

 

Where does that hose vent to? I was expecting a gas fountain on top of the headlight. Where specifically would I see the vent being restricted?

If I remove the gas cap at idle, it is bubbling profusely. In regard to running wet, are you talking about removing the spark plugs to check whether the tip is wet?

 

the vent lines usually run up around the handle bars under the pad. meaning wet, is from running through water. the gas is being pumped back into the tank through the return line is most likely the bubbles your seeing( i'm guessing). if the tank should be building pressure, that is why i suggested unscrewing the gas cap to see if it helped. it the tank of throttle bodies werent getting vented there would be issues. just follow the vent lines from down under to all the way up through to the handle bars to see if there pinched by a clamp or something. it doesnt happen very often so most likely not an issue but always good to be sure.

 

pulled it apart. All looked correct, no pinched lines

 

Most of the EFI problems (80%) relay on electric cables and cable harnesses.
Two components are usually affected by cable harnesses.
TPS and T-BAP.
First: take a closes look at the cables that are connected to the T-BAP , and the TPS.
4 wires should be connected to the T-BAP, and 3 to the TPS.

Second: run EFI diagnostics.

Use the following procedure to download blink codes (failure codes) from the EFI
module.
1. Place the transmission in PARK.
2. Stop the engine.
3. Turn the key switch to the ON position.
4. Turn the key switch off and on three times in less than five seconds,
then leave the switch on. Any blink code numbers stored in the EFI
module will display, one at a time, on the screen. The number “61”
and the word “END” displays after all codes have been transmitted.

Error 45= Barometric Pressure Sensor ( T-BAP): Circuit Low Input
Error 46= Barometric Pressure Sensor ( T-BAP): Circuit High Input
Error 22= TPS: Open or Short Circuit to Ground
Error 22= TPS: Short Circuit to Battery

If one of these errors appears, it’s probably one of the harnesses.

 

Mine used to do something very similar, and I blew out the spark plug holes, and the caps, and then I put some di electric grease in the cap, and some on the tip of the plug, and I did that a few times over a few weeks, and it was generally after alot of snow riding, or water riding, and washing, so I think I was just getting a little moisture in there, and now all is good

 

My 08 does the same thing. dealer finds nothing. runs like the timing is off, rough, no power, barley goes up a small hill. then all of the sudden full normal power then back to rough. kind of dangerous besides just not working. happened about six months ago, it stopped doing it when i took it to the dealer and has run fine till this weekend. checked the air filter, gas. anyone have this and solve it?

 

Sounds like tps needs set, takes special tools to do it,may have to see the dealer.

 

Did anyone here having this problem have a code? If you unplug a tbap or tps sensor the computer will detect the fault, set a code and turn on the CEL. The ecu defaults to preset levels based on the other sensor readings. If it starts running bad, unpkug the tbap sensor, Rev it a few times and the CEL should come on. Ride it. Does the issue still exsist or no? If so, plug it back up and then unplug the tps. Same deal. when you do this it may not run with the normal grunt. It usually runs a little rich by defualt. But it will run plenty good enough to have some fun. I have replaced tbap harnesses alot. I have also had a couple of tps issues. The tps runs of a 5 volt reference circuit. As long as the ecu see's the voltage range stay within perameters, it will not set a code. I have replaced 2 tps's because the range would not read consistant through the travel. I cant remember the readings but lets use a 1-10 example. If it reads a 1 at idle or full rest, it should go to 10 at full throttle. The readings would go such as... 1,5,3,7,10,8... It was a bad but never went below 1 or above 10 so no CEL. But it ran terrible. Just remember to check codes before unplugging sensors. This will also set codes and it may confuse you if you have codes that u caused and not stored from real issues