TPS... Some Thoughts... And Buying One?

[Tom H]

With all the talk of the TPS recently. I looked into them a bit.

Just the other day I was helping a friend with his bike. I used my digital volt meter to see if the voltage initial setting and then the sweep looked good. Well the sweep did look good. I also used Guzzidiag to look at a few things. I futzed around a bit and said ride it. Still not running right but better. Futzed some more. Still not quite right. But now he said it's when I'm going X speed in X gear. Another futz, still there. He had a spare HD TPS. I installed and adjusted it the quick way, knowing the TB was adjusted right since I just did it, to .515V. He came back and said it was cured! So my meter was not showing it being bad.

How to test one? Maybe only an oscilloscope would see the issue. Or maybe an analog meter? On this, here is a lengthy video about it.
https://www.youtube.com/watch?v=cZK9fVvNaC4

Edit: Maybe another option to test them. I always forget Guzzidiag has a graph view. I think it will graph the TPS. I'm wondering if it's sensitive enough to read an issue????

I was thinking of buying one of the HD TPS to add to my test equipment, swap it and see if it helps. They are only about $40. WRONG!!!! The HD P/N has been discontinued. Cheapest I could find when searched the HD P/N as well as PF4/c was $70. For about $10 more I could get the PF3/C from ca cycleworks and get the right one. So much for buying one for test equipment. There is a cheaper HD one, but the screw holes make it non adjustable and I don't think the sweep rate is the same as the PF3 or 4.
Does anyone know of a cheaper source for the HD one?

If your interested in trying to repair one or just what they look like inside. Give this a look:
https://www.hdforums.com/forum/ignition-tuner-ecm-fuel-injection/1322927-harley-pf4c-tps-cleaning-for-evo-s.html

Tom

[pehayes]

Tom:  Do you have GuzziDiag software and cable?  From the home page you can switch to a live-action scrolling graphical display.  Sort of like an oscilloscope.  You can slowly open the throttle and watch the graphic rise and fall as it scrolls laterally.  Not sure if it is quite sensitive enough, but should show some form of blip or glitch if you have bad internal spots in the TPS.  Just crank the hand very slowly.

Patrick Hayes
Fremont CA

[Tom H]

Tom:  Do you have GuzziDiag software and cable?  From the home page you can switch to a live-action scrolling graphical display.  Sort of like an oscilloscope.  You can slowly open the throttle and watch the graphic rise and fall as it scrolls laterally.  Not sure if it is quite sensitive enough, but should show some form of blip or glitch if you have bad internal spots in the TPS.  Just crank the hand very slowly.

Patrick Hayes
Fremont CA

I added an edit about Guzzidoiag graph function. I always forget it has a graph. Again, and as you mention, would it show a glitch??

If my friend hasn't tossed the bad one, I might install it on my bike to see if Guzzidiag shows a glitch. Or maybe see if an resistance reading on digital or analog meter will show the glitch??

Tom

[Wayne Orwig]

I added an edit about Guzzidoiag graph function. I always forget it has a graph. Again, and as you mention, would it show a glitch??

If my friend hasn't tossed the bad one, I might install it on my bike to see if Guzzidiag shows a glitch. Or maybe see if an resistance reading on digital or analog meter will show the glitch??

The old VDST software would show a glitch on the graph function. I'm not sure the GuzziDiag graph would. I've never been able to catch a bad TPS with GuzziDiag, but then I only tried once I think.

I have an actual o-scope. Hard to beat that.

[moto-uno]

  What's this VDST software you speak of ?  Peter

[Tom H]

I now actually own 2 or 3 O Scopes. My dad showed me to use them when I was maybe 10. There is a definite CRS on how to use them Shouda listened harder!

Tom

[Tom H]

Moto:

Wayne would know for sure. I believe it's the Guzzi testing software from the factory.

Tom