Ignitech TCIP4, again

[ducatiz]

very nice

[suzyj]

Wired in a 2.5 kOhm trimpot as a voltage divider, did a bit of adjustment, and it's really good now.

Ripper!

[brad black]

well, that's over my head.

you can also manually set the tps values, which is what i was doing.

I never actually realised there as an auto set thingy.

[Speeddog]

well, that's over my head.

you can also manually set the tps values, which is what i was doing.

I never actually realised there as an auto set thingy.

The Auto-set may have been an upgrade on a software revision.
I recall that the screen images that you have on your blog are a bit different from what my screen shows with the v80 software.

Ripper!

Thanks for your help! 

Now, the annoying part.

The TPS table breakpoints are coarse (40%, 60%, 80%, 100%) in the range I'm interested in.

Is there electronic trickery that can be employed to invert the voltage signal?

I assume that if I swap the +5v and ground going to the MAP sensor it will let all of the magic smoke out of it....

[Real Recognize Real]

I knew suzyj could guide me out of the wilderness!   

Wired in a 2.5 kOhm trimpot as a voltage divider, did a bit of adjustment, and it's really good now.

New graph, not all that exciting really, but I took data to confirm function, and you must have a graph to show results to the boss. 



As an added bonus, in the process of sourcing the trimpot, I found the awesome electronic supply store I've been looking for for years.
They've got a 10' x 10' wall area just for zipties, it's like a freaking candy store. 
No more trudging to Radio Shack to negotiate with ignorant dolts and buy total crap.
I can go to a real store with knowledgeable staff and get quality parts.

Speeddog,

How did you know from the 1st TPS/Voltage curves that something was off? From just looking at the plots, I assume that something was wrong b/c TPS never reaches zero. Is my assumption correct or is there another explanation? I notice after using the potentiometer that TPS reaches zero and doesn't hang at 100% as long. Very interesting thread and I look forward to incorporating your hard work over to mine when all is sorted

[suzyj]

Now, the annoying part.

The TPS table breakpoints are coarse (40%, 60%, 80%, 100%) in the range I'm interested in.

Is there electronic trickery that can be employed to invert the voltage signal?

I assume that if I swap the +5v and ground going to the MAP sensor it will let all of the magic smoke out of it....

Yes, the sensor won't appreciate that.

You need an op-amp to invert the signal. A suitable one is http://www.linear.com/product/LT1494, but any rail to rail op-amp that will run at 5v should do fine. I chose this one because they're common and the manufacturer does free samples.

Connect the power for the op amp to 5v and gnd, and wire the + input to the middle of an equal resistance divider. 2x1k resistors should be fine.

Now wire your map sensor to the - input via a 1k resistor, and connect another 1k resistor between the - input and the output pin. Then finally connect the output pin to your tps input.

If you want to trim the zero point, use a trim pot in place of the divider on the + input.

Here's a picture of what you want:



Good luck

[Speeddog]

LMFAO 

I read your post prior to you updating it with the schematic.

Ran off, googled, read up on op-amps, scratched my head, read your post again, and did this:



 Then came back to post, and found you'd added the schematic.


Good news is it's the same schematic as yours, I just didn't flip the op amp +/-, and I used the trimpot, as I just *happen* to have a very nice 2.5 kOhm trimpot. 

Scary part is I'm pretty sure I understand how it's working. 

(Truth be told, from an electronics standpoint, it's likely only a little more advanced than tying my shoelaces.  )

[brad black]

in v80, if you click on the voltage, a little up/down arrow box appears next to it and you can adjust there.

don't mean to harp, but I know I went thru this too.  0 volts has to be lower than 100 tho, so can't invert that way.  I have no idea what the above stuff means too.

[Speeddog]

in v80, if you click on the voltage, a little up/down arrow box appears next to it and you can adjust there.

don't mean to harp, but I know I went thru this too.  0 volts has to be lower than 100 tho, so can't invert that way.  I have no idea what the above stuff means too.

Yes, I played with that as well, adjusting both by filling in a number and clicking the button to automatically set it to whatever the value was at the time.
Button click is great for a regular TPS, I'm sure.

I tried setting the 0% TPS volts high and 100% TPS volts low, and the Ignetech had none of it. 
Too smart!

I'm enlisting suzyj to help me understand how to make a little magic electronic box to translate the MAP sensor signal into something that's much like a TPS signal.

As always, your input is valued, you've done quite a lot with the Ignitech.
Dunno exactly the OZ meaning of 'harping', but no problem here!

[ducatiz]

Harping-- to repeat or revisit.   To have a raging case of harpes.

[suzyj]

[brad black]

I was respectfully telling you how to suck eggs, in the full knowledge that you knew how to, but maybe there was something you were missing sort of thing.  it's been so long since I played with it that I don't recall exactly what I did, but it did give me some agro with voltages not as I expected which kind of made me give up.  ish.

[Speeddog]

No worries. 

I think I've got it worked out how to get the MAP and Ignitech to play nicely with each other.
Remains to be seen if it's worth the effort.

I'm sure it'd be easier from the electronics perspective to just throw in the towel and fit a TPS, but that's an (at best) awkward solution on carbs.

[ducatiz]

I'm sure it'd be easier from the electronics perspective to just throw in the towel and fit a TPS, but that's an (at best) awkward solution on carbs.

Yes and no.

Remember that the TDM850 used the same carbs (different spigot) and has a TPS. 

The FCRs for the TDM have a spot for the factory TPS.  I've talked with Sudco about it and they have no problem swapping a set of FCRs for the TDM with the ducati spigots and jets.

[Speeddog]

I was really thinking about the difficulties of fitting a TPS on the OEM Mikunis on the Duc.