More TPS (Throttle Position Sensor) Questions

I've followed along with all the previous post concerning the TPS adjustments with these WR's. Some don't mess with it, while others swear their bike runs better with it un-plugged. Sooner or later your probably going to have to deal with it, either to do a "off the bike" thorough carb cleaning or just a plain failure.

I feel pretty sure that my TPS is out of adjustment after cleaning and working on my carb. Now it's my turn to deal it.

After reviewing the 03 service manual (page 6-22) adjustment is made with a digital volt-ohm meter. So here's where the splitting hairs - technical questions come in.

Manual states, first set Idle Speed Adjustment (page 3-19)

Acceptable engine idle speed range 1700 - 1900 rpm.

Second,with engine running, using a digital volt-ohm meter measure the TPS output voltage. Acceptable range 0.58 - 0.78 volts.

Has anyone experimented with these range settings? Like setting the RPM to 1900 and volts to 0.78 or 1700 RPM and 0.58 volts and tested performance results? It may be that it doesn't matter either way as long as the TPS setting is within range spec but it might. It certainly seems like slight subtle adjustments matter to this carb.

I have a digital volt-ohm meter but I don't have a tach to properly set my exact idle speed to make TPS adjustments. (I need to have a good tach on hand anyway, someone recommend a good one to buy). Nevertheless I'll have to make a proper TPS adjustment. Let me know your experiences.

BTW: When I was at the local dealer the other day I happen to see the maintenance supervisor walking through the showroom and mentioned this whole scenario to him and he either didn't understand what I was talking about or I didn't understand his different method of setting the TPS. He described making the adjustment with the engine off and with throttle wide open.

I've followed along with all the previous post concerning the TPS adjustments with these WR's. Some don't mess with it, while others swear their bike runs better with it un-plugged. Sooner or later your probably going to have to deal with it, either to do a "off the bike" thorough carb cleaning or just a plain failure.

I feel pretty sure that my TPS is out of adjustment after cleaning and working on my carb. Now it's my turn to deal it.

After reviewing the 03 service manual (page 6-22) adjustment is made with a digital volt-ohm meter. So here's where the splitting hairs - technical questions come in.

Manual states, first set Idle Speed Adjustment (page 3-19)

Acceptable engine idle speed range 1700 - 1900 rpm.

Second,with engine running, using a digital volt-ohm meter measure the TPS output voltage. Acceptable range 0.58 - 0.78 volts.

Has anyone experimented with these range settings? Like setting the RPM to 1900 and volts to 0.78 or 1700 RPM and 0.58 volts and tested performance results? It may be that it doesn't matter either way as long as the TPS setting is within range spec but it might. It certainly seems like slight subtle adjustments matter to this carb.

I have a digital volt-ohm meter but I don't have a tach to properly set my exact idle speed to make TPS adjustments. (I need to have a good tach on hand anyway, someone recommend a good one to buy). Nevertheless I'll have to make a proper TPS adjustment. Let me know your experiences.

BTW: When I was at the local dealer the other day I happen to see the maintenance supervisor walking through the showroom and mentioned this whole scenario to him and he either didn't understand what I was talking about or I didn't understand his different method of setting the TPS. He described making the adjustment with the engine off and with throttle wide open.

If you are measuring anything across the unplugged leads of the TPS it's resistance, not voltage. I don't see how you can get a voltage reading as all the TPS is is a variable resistance (rheostat). I'm confused... :cry:

Some don't mess with it, while others swear their bike runs better with it un-pluggedQUOTE]

Have you tried runing with it un-plugged ? :cry:

If you are going to measure the output voltage you will have to use two propes and come into the back side of the connector along the wires. My manual shows this, and I am also an electronics tech. Very common practice. Hope this helps.

Josh

If you are measuring anything across the unplugged leads of the TPS it's resistance, not voltage. I don't see how you can get a voltage reading as all the TPS is is a variable resistance (rheostat). I'm confused... :cry:
If you are going to measure the output voltage you will have to use two propes and come into the back side of the connector along the wires. My manual shows this, and I am also an electronics tech. Very common practice. Hope this helps.

Josh

Ahh...thanks :cry:

No I haven't tried running it yet with the TPS unplugged but I intend to possibly this weekend.

I haven't tried to set the TPS with any method yet, I just suspect it's out of adjustment. I just really wanted to know if someone had experimented with the specification range listed in the manual and wanted to know how sensitive the setting might be. We spend all this time dialing in jets it just stands to reason that the TPS adjustment probably needs to be adjusted and monitored with routine carb cleanings.

I just measured the static resistance of the TPS sensor on my bike and it is off spec. at closed throttle. Book says 0-3K ohms, and mine is reading 3.99K. At WOT, it is OK. I tried adjusting the sensor, and it hits the stop at 3.8K at closed throttle.

It seems this sensor is merely to tell the ignition system where to tune in regards to throttle. This sensor CANNOT change fuel air ratio or anything, because the jets do that, and they are all fixed hardware.

I don't see any reason this bike wouldn't run without it. I am going to disable it, and see if bike runs ok.

I wouldn't run very far with mine unplugged. It's really there to adjust ignition advance and maybe a few other things. Here are the two risks:

1. Too advanced means overheating.

2. Too retarded means loss of performance.

I would find a way to adjust it properly or take it to a good dealer service dept for same.

...I have a digital volt-ohm meter but I don't have a tach to properly set my exact idle speed to make TPS adjustments. (I need to have a good tach on hand anyway, someone recommend a good one to buy)...

I don't know of any specific models off hand, but some of the nicer/newer digital multimeters have a tachometer function on them. I'm sorta half-a$$ looking for one myself, as my old analog multimeter is way out of adjustment, & I'd like to have the tach feature too. If I run across anything soon, I'll try & remember to post it in this tread.

Man would I love to be cruising down the street at a steady speed and not have to feel the miss or whatever, thats my only complaint so far, I did unplug my tps and the bike smoothed out, no miss, I was planning on plugging it in when in the woods up north and when road riding at home running it unplugged, now not so sure?? don't want to hurt the engine, maybe reseting the TPS will solve this problem. Good luck.

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