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Hey guys,

Trying to get some technical info on the front Temp Sender (on top of thermostat housing) on a 1.6.

1. Do the 1.6 and 1.8 share the same sensor?

2. Does anyone know the Ohms (resistance of the unit at various temps?)

3. Anyone have a wiring diagram?

I am trying to find out if the factory unit will work with a Electronic water pump setup.

Thanks very much!

That sensor is a gauge sender and isn't used by the ECU to managed the cooling/fuel during warm up. It is only used to send a signal to the gauge to show when the car is warm or still cold! I would suspect it is a fairly poor sensor (sender might be the right name) and it only goes to GND when it hits the target temp... not used to typically have a scaled resistance for temperature measurement (as that's the sensor at the back of the head)

Really? are you sure? i thought the one at the rear of the engine was the gauge. (under the coils).

If so then i guess i need the technical details from the one at the back of the engine!

There are 3 temp sensors on an na6 iirc.
1 temp switch (1 wire) located on the thermostat housing for the fan. It switches ground when the temp is reached to turn on the fan.
1 temp sensor (2 wire) that goes to the ecu. At the back of the engine
1 temp sensor (1 wire) at the back of the engine used for the temp gauge. Earthing it will result in the gauge reading max temp iirc.

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Look up neomiata for wiring diagrams

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Sage wrote:Really? are you sure? i thought the one at the rear of the engine was the gauge. (under the coils).

If so then i guess i need the technical details from the one at the back of the engine!

Oops yeah you are right... the front sender is just a fan switch and the back of engine senders are the ECU/temp gauge. Though I'm sure in my testing the sensor/sender for the gauge was fairly raw and seemed to focus around either high-resistance (cold) and quickly move to low-resistance (warm) - unlike the ECU sensor.

G

found the kiloohms..

if anyone is interested.

-20c 14.6 - 17.8
20c 2.2 - 2.7
60c 0.29 – 0.35

K ohms

It looks like it is very similiar to the 1.8 as far as resistance is concerned though the 1.8 does not do the negative Celsius reading.

What about higher temps? Given the car generally runs around 90°C

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What ecu will you run? Consider what will happen if the shared temp sensor for the gauge and the ewp fails neither your or the water pump may know that your engine is cooking...


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That info i posted is from an enthusiast manual i have, written by one of the designers of the original Miata so i think its trustworthy.. (book published in 1998).

http://www.amazon.com/Mazda-Performance ... 0760304378

I assume that the front sensor doesnt care what the temp is precisely only that its above 60c so open the thermostat and let water go through the engine.. after the thermostat is open it doesnt matter if it gets hotter than it should it will simply be the best the cooling system can provide.

if it does get too hot then the driver looks at the gauge (from back of the engine) - stops the car and begins troubleshooting as to why the system is failing..

sailaholic - was that question to me? if so i will still run the rear sensor as well for the gauge just want to replace the front sensor with the one provided with the EWP though different thread so looking for a replacement with same resistance properties..

though i do run an adaptronic already...