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JVP

Switch for the TPS

17 posts in this topic

Has anyone installed a switch for the TPS? Based on all the past posts on this subject the TPS is useful for trail riding and a problem for long wide open street or road riding. I would like a choice and I thinking of hooking the TPS to a switch on the handlebars. Any ideas? :cry:

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I'm new and learing here but are you talking about a switch for the "Grey wire"? :cry:

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Sorry, No. The TPS is the Throttle Positioning Sensor is an electronic unit attached to the carb.

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I think somebody on here has done that, not sure who though. Depending on how may wires the thing has, or how many actually need to be switched to activate/deactivate it properly, I would think it'd be fairly simple to do, maybe even with an aftermarket headlight bar switch, or a headlight switch from an older WR.

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TPS is usually an input to the ECM for ignition timing and I think I saw 3 wires going to it. If its a mechanical switch, it would usually be a double pole double throw (DPDT), one set of contacts is closed for idle, the other is closed for WOT and both are open anywhere in between. If its a solid state switch (and I suspect it is) it will have a VC voltage or a voltage constant (stable voltage, usually 5 V), input voltage to the TPS, a ground and an output variable voltage (input to the ECM) on the remaining wire that will vary, usually between 1-4 volts, a 0 volt reading means a short, while the full 5 volts means an open. Without looking at the electircal wiring diagram, I dont know if this system is a standard setup or unique! ANd with is disconnected, I will just default to a set spec. Dont know if this info will help, but thought I'd chime in. It appears it would be tough to do. I suppose one could just find the common (mechanical) or the ECM input (solid state) and install a switch in those wires, and give it a try. I did have a switch on my old WR grey wire so I could have it YZ or WR timed, and to be honest, I didnt feel a difference, but I didnt spin it up real high as I trail ride, not race. So the same setup may work for the TPS too :cry: :cry:

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Put a switch on the constant voltage wire. The wire that measures 5v regardless of throttle position is the constant voltage wire. That wire would disable the TPS

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The TPSensor is a potentiometer.....one wire to +12V, one to ground and the wiper to the Ignition box. The voltage out tells the box where the throttle is......pretty simple.

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It's so easy to unplug and plug in I just assume do it that way. With my look I'd screw something up when adding the switch. If I am right you have to shut the bike off to reset the TPS much like with the grey wire mod switch.

I.E-You can't be cruising along and flip the switch and have things switch over.

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I.E-You can't be cruising along and flip the switch and have things switch over.

You can't? This is news to me, I just purchased a '04 and haven't had a chance to ride it yet so I can't say either way. Is this a proven fact or what? Just curious so I know what to expect.

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This is proven fact from what I have read. Do have the mapping change the engine needs to be shutdown and started back up. The CDI doesnt get the new map until this time, I could be wrong but I remember reading this.

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You can switch it over no problem while riding. What would happen if you were riding and the connection went bad? The bike would keep running but without reference to throttle position. The same as turning the TPS off. But if you start the bike with the tps disconnected, you may have to restart if you reconnect.

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You can switch it over no problem while riding. What would happen if you were riding and the connection went bad? The bike would keep running but without reference to throttle position. The same as turning the TPS off. But if you start the bike with the tps disconnected, you may have to restart if you reconnect.

That may be right, like I said if it's anything like the grey wire mod you can't simply switch it with the bike running. The TPS doesnt run through the CDI so it sounds like it's exempt from that theory.

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That may be right, like I said if it's anything like the grey wire mod you can't simply switch it with the bike running. The TPS doesnt run through the CDI so it sounds like it's exempt from that theory.

In my electrical schematic here, the TPS runs directly to the CDI. But still, you will prolly have to restart the bike if you are to turn the TPS back on. Turning the the TPS off you won't need to restart.

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I really don't see an advantage of putting in a switch for the TPS. The main function of the TPS is to advance the timing during part throttle, low load operation. Most bikes, YZ 450s notwithstanding, should run better with the TPS connected.

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sounds like a good idea, there must be a way to do it, i might have a play with mine and let you know what happens

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In theory it should carberate a little better and get better fuel economy, but that has not been my experience. My '04 runs much better with it disconnected, especially on connecting roads, the street, or anywhere that you would hold a steady state throttle. I don't notice a difference on the trail or mx track. So, mine is staying disco'd. YMMV

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