Throttle Sensor

[steviesi]

Hi all,

Can anyone tell me how to test if the TPS is working as should?

I've checked the operation of it as Haynes recommend, i.e. disconnect it, rev the engine to a steady 4000 rpm while connecting it back up and the engine revs should rise. Mines don't, at least not noticeably. I would have expected to reconnect would have a significant effect.

I've tested the TPS at the Ignition Control Module connector as per Haynes Manual and the resistance readings are as required. Fully closed was slightly too high at 560 ohms and resistance increases and decreases as throttle opens and closes.

So I thought then, maybe the ICM needs replacing. But then my friend reported that he tried to check the operation of his TPS in the same manner and there was no change in RPM on his bike either. So either we're using the wrong test or both our TPS aren't operating as should.

I'm hoping it is the TPS because the bike runs like sh1t, especially low down, which all fit in with TPS symptoms. The carbs have been cleaned and balanced professionally.

Any help appreciated

[VTRDark]

I'm guessing your reading while testing would be relevant to what setting the TPS is at to begin with.
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=29429

I'm hoping it is the TPS because the bike runs like sh1t, especially low down, which all fit in with TPS symptoms. The carbs have been cleaned and balanced professionally.

Runs like sh1t can mean anything. But if your referring to a rough idle and the bike is not be very smooth at low revs then setting the TPS to 500 +/-10 ohms will help.

(:-})

[steviesi]

[quote="cybercarl"]I'm guessing your reading while testing would be relevant to what setting the TPS is at to begin with.
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=29429

quote]

Thanks CC. I did read your excellent article prior to writing in. My TPS reads 560 ohms, which is very near the 500+/- 10% quoted.

Once the bikes all back together is there a way to check the operation of the sensor?

Thanks

[VTRDark]

As far as I'm aware there are only the tests that you have used in the Haynes manual. You may want to compare them to the tests in the Honda workshop manual
http://www.vtr1000.org/phpBB3/viewtopic ... 31&t=18025

One thing to be aware off with these test is for accuracy you should use a separate RPM meter from the one on the bike. For one of the tests it says

Connect the throttle sensor connector when the engine speed is 3,500 rpm or above (throttle angle is 4-12 degrees)

I'm not sure where you take the degree reading from but I think it is suggesting you can use a timing light. With a timing light (strobe) pointing at the flywheel timing marks, and when you rev the bike, I would have thought you could see it advance and retard. TBH I'm not sure as I have not done these tests before or even stuck a timing light on the bike.

(:-})

[sirch345]

This topic is being moved into the "Workshop" section,

Chris.