So who can tell me what function this plug plays (in red) besides plugging the hole? It's on the back of the coolant filler neck area. Directly below it is the stock coolant level sensor or what is now the Microtech water temp sensor.

The reason I ask is I would like to move my PLX water temp sensor from its current location (in blue) to the plug (in red) if this is possible. Would get the temp sensor away from the heat of the turbo.

Thanks.

 

I only have a third gen water neck to look at, but a sensor is supposed to go in there cause that plug doesnt look stock so i dont see why you couldnt put a sensor there. now if it were a freeze plug that would be a different story.

 

On a 13B-REW, that is where the stock water temp sensor goes, and under that is the sensor that controls the fans.

Hope that helps a little..

L8R

 

David,

As long as the business end of your sensor is submerged in coolant, the radiant heat from the turbo will not affect it at all. The wiring & connector will melt long before the accuracy of the sensor is affected....

 

With the heat blanked on the turbo, I don't think you need to worry about that sensor getting a false reading. If you are really worried you could fabricate a heat shield out of sheet metal to put between the sensor and turbo.

 

Like I had mentioned before, proximity to the compressor won't cause you any issues

 

Thanks guys for the help. I like this location better, even if it doesn't have an impact on the sensor temps. I should know more soon as I have now bought the Microtech laptop adapter so I can compare the Microtech sensor to the PLX sensor readings to see if they are the same.

 

There is more to this then just gauge accuracy, he is trying to get it to read properly during warm-up. With the sensors current location there is no reading until after the thermostat opens.


The circled plug is is where the OEM water thermosensor should be, this is the sensor that tells the Microtech the water temp.

The gold sensor below that is where the OEM fan switch is located. Someone may have installed a water temp sending unit in this position, but it is not the one that the Microtech is expecting to see.

In your other thread I asked you what you were doing with the nipple on the top of the WP housing, I can see from this picture that it has been removed. You can relocate your gauge sending unit to the spot with the plug marked "8.8 JH".

Have you received the dongle yet?

I would not be too quick to use the water thermosensor location as you may need it once you find out what your Microtech is reading.

 

Yes, I have the dongle and "connected" the laptop to the Microteh over the weekend. What a PIA that was as the USB to serial adapter was not working. Rebooted a few times and it magically started to work (yes, I had already set the COM port to 1 and then to 2).

So you are saying the top plug I circled is a Microtech unit? It's not attached to anything so how does this connect with the Microtech EMS if I read your post correctly? Something internal? And the 8.8 JH can be removed and this spot used for the Microtech? If this is true, is there anything special about removing the plug other than popping it out?

What is interesting about the current location is it is past the thermostat right? But it gets readings and it shows a warmup pattern, slowly and low at first and then it quickly warms up. This must be the effect of heat at first and then coolant. I had always wondered why the oil temps warmed up so quickly but not the water temps. FYI - regardless, my oil temps are now consistently 7-9 degrees C less than my water temps so the thought that my PLX sensor location is not a good one is still a strong possibility. And if it is past thermostat, it should be moved anyway.

 

No, I said: "The circled plug is where the OEM water thermosensor should be, this is the sensor that tells the Microtech the water temp."
You just have a plug there, no sensor at all. This is where the OEM sensor SHOULD be. The sensor below it is the location for the stock fan switch, something else has been installed there.

I will clarify, the Microtech is capable of using all the stock sensors, your car went through so many ECUs that the stock parts were removed long ago. Most likely you have a GM style sensor left in there from some previous unit like the Haltech.

The 8.8 JH is just another plug that can be unscrewed. The PLX sensor can be relocated there, this is where I have my Defi sensor. How to remove it is up to you, it is not a factory part, someone along the way in your cars bumpy journey installed it.

The PLX operates slowly because there is a small amount of coolant that makes it through the thermostat, the point when it opens is when your gauge is operating quickly.

What are your water temps on the Laptop gauge? What is your fan ON temp set at?

 

Got it, sorry for the misunderstanding. So as I understand it, either of the plugs will work, the one I circle or the 8.8 JH one you have identified. I'll look further into this once I can compare the Microtech reading to the PLX water temp.

I haven't yet monitored anything via the Microtech. Just got it hooked up and made sure I could connect. FYI - Microtech really needs to update the whole laptop adapter thing. It's cumbersome, costly, and completely not needed in today's world. Or at least do it thru a USB connection.

I did check the fan ON setting and it is at 88C.

 

Okay, Jesus confirms the GM style sensor in the pic is used for the Microtech and he indicates either of the other two plugs would work for relocating the PLX sensor.

I did fire up the car today and checked the Microtech reading versus the PLX reading and yes, they are consistently 5-7 degrees celsius off, with the PLX reading being the higher of the two. So, the good news is I don't have a water temp issue (unless the Microtech is off but I doubt it) and my temps have gone no higher than 95C even during the hottest of FL days. I can live with that.

So I'll be moving the sensor back behind the thermostat soon.

 

95* still pretty hot...

 

That's just above 200F. Not bad by my standards and that was about one month ago when it was 95F outside and the humidity was insane. The thermostat doesn't even open up until 180F.

The FD manual says at 95C the engine is fully warm. Hot is about 105C.

 

You may just want to verify that the sensor being used is within the range that the Microtech uses. If the sensor reads incorrectly (example 92C=86C) then your fans may be coming on at a much higher actual temperature then what the ECU is reading.

Microtech/FD water temp sensor spec:
-20C is 14 to 17K OHM
20C is 2.2 to 2.7K OHM
80C is .29 to .35K OHM

 

The sensor used for the Microtech (controls the ECU) is the GM style one shown in the pic and was setup by Jesus for Microtech use so I think I am good to go here. The PLX sensor that is reading higher doesn't control the Microtech but is used by me to monitor water temps. I am moving it to one of the two locations shown in the pic that are pre-thermostat so I should then have consistent readings (assuming the calibration on both units is close) to the Microtech and to the PLX gauge.

I am pretty confident the GM-style sensor is correct as we used a thermal laser gun to uncover the issue with the PLX sensor (it showing a too high reading). The Microtech water temp readings were bang on with the thermal sensor.

 

Found an adapter to go from a 12mm X 1.5 hole to a 1/8 NPT so I am good to go with little work