disconnect TPS = no more hanging idle

[Riel250f]

2000 426, new everything in the motor.

have a hanging idle, tried jetting for days to no avail, no

air leaks. I disconnected the TPS and it cured it.

So went to the manual, checked resistance, and is at 5K = in spec.

measured at yellow wire and have 1.2K, should be @ .75 or .65K ohms.

so loosened the tps and rotated it clockwise, could only achieve 1.1K

and it stops. can't go clockwise any further.

checked the voltage and that was in spec at 5V.

can anyone help? I'm at a loss now.

Don't really want to ride the bike with the TPS disconnected.

[Chas_M]

I haven't heard of this particular situation before, however running with the TPS disconnected is not harmful to the engine in any way.

[grayracer513]

measured at yellow wire and have 1.2K, should be @ .75 or .65K ohms.

so loosened the tps and rotated it clockwise, could only achieve 1.1K

and it stops. can't go clockwise any further.

That indicates a failed TPS.

You can run with it disconnected, but it may affect part throttle performance. The TPS allows the CDI to control the ignition advance relative to engine load as well as engine speed, giving the ignition map its 3rd dimension. With the TPS open (disconnected) the CDI assumes full throttle at all times, and sets timing based only on RPM. Full throttle performance will not change, but part throttle, such as cruising at speed, and moderating the engine in a turn, may not be as clean as with the TPS in place.

[Riel250f]

:worthy:

THANK YOU!

[Photojojo]

I'm having a some of the same symptoms with my TPS on an 03 WR450. I have a bad surge pretty much all over the throttle range when holding steady in one spot. Mostly it's noticeable on the road. I disconnected the TPS per the FAQ's and it seemed much better. I checked it with the meter and it measures .65. That's within range according to the owners manual. Should I try and adjust it to get rid of the surge with the TPS connected? Should I twist a certain direction?

[thumper_jockey]

My 02 WR250 is having the same problem. I unplug the TPS and it seems better but now it won't idle.

I turn up the idle screw so it will idle and now the hanging idle is back as soon as I rev it.

It was running great, and then all of the sudden...

BTW the TPS is out of spec but it sounds like people are getting away without it anyway. Will the TPS effect my idle this much?

[grayracer513]

My 02 WR250 is having the same problem. I unplug the TPS and it seems better but now it won't idle.

You're in the wrong forum, but I would check your intake valve clearance first thing on a 250F.