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There was some discussion last night in the V6 MR2 Facebook group that I thought I would share here as well. I didn't know this was a thing, but for the last 6 or so years I've been using this 3 pin coolant sensor on my engine. I had my harness made by Doug (WireGap Inc.) and that's the way it came back to me. The advantage to this sensor is that it combines the signal for the ECU and the signal for the cluster into one sensor. I found the sensor on a Toyota Echo in the junkyard, but when I search for the part number it also comes up on some 2azfe Camrys.






 

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Don't know why the heck they did it that way, instead of having one sensor read by the ECU, and then the ECU sending the reading to the cluster.
 

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Don't know why the heck they did it that way, instead of having one sensor read by the ECU, and then the ECU sending the reading to the cluster.
We can speculate on the why... but I am certainly glad they didn't. It makes things like engine swaps and aftermarket ECU's just a little bit easier when systems aren't too heavily combined. Having a dash that relies on the factory ECU would be a pain (and is a pain in a lot of modern cars, I am sure).
 

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... It makes things like engine swaps and aftermarket ECU's just a little bit easier when systems aren't too heavily combined..
Agreed.

When EFI was introduced in the 80s, it was as a stand-alone system with all its own sensors. Same with emissions controls in the 70s. But, when they got around to integrating, they integrated everything that they could. Going to the trouble to just put two sensors in one pod is just hinky. :dontknow:
 

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Can someone please dumb this down for me? I have the three pin sensor and the corresponding connector. out of my harness I have he gauge wire (yellow with green stripe) and from the old two pin connector I have a brown wire and and white/black wire. Which wires need to go to which pins 1,2,3. Thanks for your help.
 

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Hopefully I can make this SUPER clear as I was a bit confused from these directions. I just completed the swap to single sensor.

Parts needed:
ACDelco 19322820
https://www.amazon.com/gp/product/B01E6FUDVA/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Three position connector. Loose pins or pig tail are both available here.
3 Way Toyota ECT, CLT, & Temperature Sensor Plug Connector Kit (Toyota # 90980-11451)
https://www.bmotorsports.com/shop/product_info.php/products_id/4141
https://www.bmotorsports.com/shop/product_info.php/products_id/4142

OEM 2gr coolant sensor has two wires, color may differ depending on your harness or wiring so its easier to look at pin positions.
Pin one from the two pin connector goes to pin 1 of the three pin connector
Pin two from the two pin connector goes to pin 2 of the three pin connector
Single OEM gauge wire goes to pin 3 for the three pin connector

Also note the pin positions are printed on the back of the connector!

When testing the sensor it has to be grounded for the OEM gauge to work or screwed into the coolant neck. OBD works with no extra ground.

:)
 

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I installed this setup but am running into a problem: my gauge on the dashboard reads at the halfway point when the car is cold and on. This causes it to go into the red when running the engine. Do I need to add more resistance to the line going to the gauge? 2008 2GR into 1991 NA chassis
 

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If you have used a non-OE sensor then all bets are off. I ran into so many problems with after-market sensors over the years that I quite using them a long time ago.

If you do have an OE sensor, and it is reading incorrectly, then you need to verify that its calibration is the same as your original sensor. For this you need a stove, a pot of water, a thermometer (optional), the original sensor, and an ohm-meter/multi-meter. Follow the procedure listed in the BGB in the Combination Meter (aka cluster) section for checking the sender. There is a table of resistance versus temperature for the sender. Verify is that the new sender and the original sender have the same resistance at any given temperature.
 

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Does anyone know if the 91 NA temp sensor was part of the engine harness? Because I do not see a plug on the body harness for it. Had my engine harness modified with a newer highlander one which is a 2 pin plug.

Is it possible Wiregap could have made my 2 pin plug compatible with my dash? I seriously cannot find it on my body harness
 

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Does anyone know if the 91 NA temp sensor was part of the engine harness? Because I do not see a plug on the body harness for it. Had my engine harness modified with a newer highlander one which is a 2 pin plug.

Is it possible Wiregap could have made my 2 pin plug compatible with my dash? I seriously cannot find it on my body harness
In the MR2 the gauge sensor plug is part of the engine harness. There is no way they could have made the 2-pin 2GR plug feed into the gauge, the required output simply isn't there. You would need to replace the 2-pin plug with the 3-pin plug. I would think that wiregap would have either done this (this 3-pin setup has gotten pretty common I think), or included a single wire for the gauge, in which case you would just need to combine that single wire into the 3-pin plug.
 
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Yes, I have been using this sporadically since I did my brother's 2gr back around that time. Used to be my standard until people complained about it. Since people are asking for it again (I've had to send out a number of 3pin
pigtails) I'm making it the standard again. If I did your harness, and you want to run the 3pin temp sensor, I'll send you the connector.
 

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Yes, I have been using this sporadically since I did my brother's 2gr back around that time. Used to be my standard until people complained about it. Since people are asking for it again (I've had to send out a number of 3pin
pigtails) I'm making it the standard again. If I did your harness, and you want to run the 3pin temp sensor, I'll send you the connector.
People may well be asking for it because I'm making modified water necks without an extra port, and telling people to just use the 3-pin sensor. I've done almost two dozen of them so far this year, so there are definitely more than a few people out there running this now.
 
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