So, the next time you have your TPS checked, you'll know it's right, won't you!! Recommended only for insomniacs :wink:
As i have recently become fascinated by all things Arduino and stepper motor, a little too fascinated perhaps, i found this cooler than a very cool thing. I am glad there is someone going to this much effort to empirically test parts. A little less glad to learn about the industry standard " 4 point test". How many customers have been told their TPS is good and subsequently spent who knows how long chasing ghosts?
My thoughts entirely, plus the thing that I find utterly astonishing is the apparent amount of fails. Reading between the lines, Magneti Marelli have a lot to answer to. I guess it's a case of trust your instincts, but who over here in dear old blighty can undertake such testing? Postcards not necessary.
The difficulty is machining the accurate receptacle for each type of TPS and i dont have those facilities. The Arduino and stepper motor part is actually easy and if a graph in excel is good enough as a graphical representation of the results then this might be worth doing. I am not taking my TPS off so does anyone know the dimensions of the keyway that they fit onto? Doubt if all ducati TPS's are the same but one example picture with measurements would be very useful.
He built that test rig using a 3D printer. Is doing another project for measuring belts. Clever fella.
The belts thing is done, look at the end of that you tube when the others come up. His rig is impressive but the functionality to provide very accurate graph of the TPS curve can be done more simply. Who has a suspect one ?
From what I can see the only way to prove absolute continuity, would be to build two of the buggers. Theoretically they should both read the same, interesting project.
That is quite good test but not conclusive. Rotary potentiometers suffer badly from vibration and heat and moisture, as they have a copper winding. I did some extensive testing with some Swindon roller barrels on a Spiess unit that we had trouble with. We eventually found that the problem lied in the pot being shaken at some 11ooo rpm causing it to lose the output signal and dropping below 5 volt which in turn caused a misfire. We had the pot tested in a lab on a bench and it came back good, but this could not replicate the environment in which it was subject to. We replaced the very expensive pot and it cured the problem.
The test rig is very impressive and automates an otherwise laborious job of testing at many points - presumably this is why the "industry standard" 4-point test is done instead. The video does raise some questions though about what actually constitutes a fault and what does not. As he says in the video, the TPS on his own bike tested as faulty but he never noticed it while riding. Does that mean it should be replaced? He doesn't say but I think the answer is obvious. He also says that they are a real pain to get at and get off the throttle bodies. Having said all that it is a nice way of quickly dismissing a very obviously "bad" TPS before it gets sold, and gives some kind of guarantee that what you are buying will work.
I'm going with a .9 degree, 400 step stepper ( 'cos i have one lying around) in half step mode. The TPS i have moves through about 100 degrees rather than 90 so i will read 222 points and graph those in excel. I realised i don't need a fancy jig to place the sensor i just need to hold it still.
This is a graph of an old TPS i had lying around, think its from a volvo. 222 points representing 100 degrees. .45 degree/step. Does not look like a good sensor to me but its the first one i have done this to. wide open throttle should be 5 volts which would be represented as a value of 1023 and this never gets above 700. 12:06 Just done a little more research and have discovered that it is normal for the WOT reading to rise only to a level somewhere below full 5 volts.
Does anyone have a suspect TPS that will otherwise get thown out? It would be cool to characterise its response curve as above.
Phil do you mean you'd like me to? Happy to if that's what you are asking but somehow i don't think it is.
The TPS on my SSie is suspect, the bike runs rough at 3000rpm and Glen at Parkinsons thought it could be TPS not sending correct voltage. Can you test it for me please? Its one of these.. DUCATI MONSTER, SS Throttle Body Sensor TPS Potentiometer CTS175-522 Adjustable | eBay
Yes i'll give it a go if we can make the logistics work. I am in hertfordshire. If you want to send it to me i can test it. Exact address via P.M if you want to do this. If its on the bike currently you would have to remove it and then it needs to be reset after. If you are not confident doing this then perhaps this is not a plan for you. It'll be cool to see the graph though
