1.6 Auto TB for TPS
#1
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I have an auto TB with TPS.
from what I've read I just need to swap the WOT signal from the MT with the TPS signal from the AT.
![](https://www.miataturbo.net/braineack/MS/autoTB.jpg)
If I've read correctly:
RED / BLU - Wiper (TPS)
BLK / LTGRN - Ground
RED - Switch Idle
LTGRN / RED - 5vref
so as long as I just swap my WOT signal for the TPS signal I shoud be golden right? Do I need to do anything else special to the board? Just in MT correct?
here's the kicker...dont have the connector. I know I can determine the TPS signal...what about the other two?
from what I've read I just need to swap the WOT signal from the MT with the TPS signal from the AT.
![](https://www.miataturbo.net/braineack/MS/autoTB.jpg)
If I've read correctly:
RED / BLU - Wiper (TPS)
BLK / LTGRN - Ground
RED - Switch Idle
LTGRN / RED - 5vref
so as long as I just swap my WOT signal for the TPS signal I shoud be golden right? Do I need to do anything else special to the board? Just in MT correct?
here's the kicker...dont have the connector. I know I can determine the TPS signal...what about the other two?
Last edited by Braineack; 07-03-2007 at 03:56 PM.
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Don't have an auto TB here, but the manual tps I have has a removable plastic cover that exposes the wiring.
I guess there will be 4 contacts in there. Wire colors should be obvious once the cover is removed, but poke around with your DMM set to measure resistance. Finding the ground wire should be easiest--it is usually black. Put one probe on the ground, and then check the other 3 pins and watch the DMM for change in resistance with change of throttle position. The one that shows the same resistance despite throttle position will be the +5V in.
I guess there will be 4 contacts in there. Wire colors should be obvious once the cover is removed, but poke around with your DMM set to measure resistance. Finding the ground wire should be easiest--it is usually black. Put one probe on the ground, and then check the other 3 pins and watch the DMM for change in resistance with change of throttle position. The one that shows the same resistance despite throttle position will be the +5V in.
#3
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The easiest way to check a TPS is to unplug it and put an ohmmeter on its pins. Observe the resistance as the throttle opens and closes. Each pair of pins will behave differently:
The resistance between the VREF and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the VREF and signal pins will be high with the throttle closed and low with the throttle wide open.
The resistance between the VREF and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the VREF and signal pins will be high with the throttle closed and low with the throttle wide open.
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nope DIY, not PNP.
My plan is to run three wires off the new TB. Ground, Switched Idled, and TPS Signal to my oem harness. Basically just replacing the WOT signal from before with a TPS signal. So no need to run a new wire to the MS.
My plan is to run three wires off the new TB. Ground, Switched Idled, and TPS Signal to my oem harness. Basically just replacing the WOT signal from before with a TPS signal. So no need to run a new wire to the MS.
#7
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If R1 is the resistance between ground and signal, and R2 is the resistance between signal and +5v, then:
signal = 5v * R2 / (R1 + R2)
The 5v ref needs to come from the MegaSquirt.
I apologize if I'm missing something, because I'm not familiar with the 1.6 setup, only my 94 setup. And I'm running standalone so I don't have a stock ECU to worry about.
-Mike
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ok, hows this sound.
I bring in a 5vref into the TB. from the LG/R wire from my AFM harness.
wire switch idle to switch idle in the harness
wire the TPS signal to WOT in the harness.
and GND to GND.
Looking at the diagram the AT's TPS signal goes to PIN 2M and the MT's WOT to 2L...Do I assume my harness should have the wire and whould I wire it there and leave the WOT pin unused, or should I just wire the TPS to the WOT pin?
I bring in a 5vref into the TB. from the LG/R wire from my AFM harness.
wire switch idle to switch idle in the harness
wire the TPS signal to WOT in the harness.
and GND to GND.
Looking at the diagram the AT's TPS signal goes to PIN 2M and the MT's WOT to 2L...Do I assume my harness should have the wire and whould I wire it there and leave the WOT pin unused, or should I just wire the TPS to the WOT pin?
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I don't have diagrams or parts in front of me to verify wire/color codes. But what you need to do is replace the WOT switch signal with the variable signal. The other wiring is the same.
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here the diagram with labels.
The signal wire for WOT with the Non-TPS and the TPS wire go to different pins. If I take the TPS wire and wire it the WOT to 2L will I run into probelms? or should I wire it into the ECU through 2M, or does it not matter since the MS runs the show?
![](https://www.miataturbo.net/braineack/random/tps.jpg)
Last edited by Braineack; 07-03-2007 at 06:55 PM.
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yeah those differences are for the manual vs auto ECU. Has nothing to do with the MS. I would bring the variable signal at 2L in place of the WOT switch signal. That way you use the existing wire and don't have to dick with moving a pin in the harness. The key is you may have to modify your MS board to accept the signal. My board requires adding a jumper to meet the 2L wire and removing a couple of resistors.
MY MSPNP has +5V at 1N. It really doesn't matter where you get the 5V from though. Nor, really does it matter where you ground. If there's a voltage offset, so what, the ecu is programmable to compensate.
Ben
MY MSPNP has +5V at 1N. It really doesn't matter where you get the 5V from though. Nor, really does it matter where you ground. If there's a voltage offset, so what, the ecu is programmable to compensate.
Ben
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ok that's what i thought. I dont believe i have to do anythign with my megasquirt, just give it the signal. I'll just pull the 5vref from somewhere in the bay in the tps. the rest is easy enough....now to find a pigtail.