any idea this sensor is for?
Water Thermal Sensor. The stiock ECU uses that temp reading as to retard the car during warm-up. If it's not working, the car will probably run similar as if the MAP sensor is disconnected.
Originally Posted by Mahjik
Water Thermal Sensor. The stiock ECU uses that temp reading as to retard the car during warm-up. If it's not working, the car will probably run similar as if the MAP sensor is disconnected.
Actually, the lower one-wire sensor is the fan thermoswitch. It grounds out at a certain temperature to kick the fans on.
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
Originally Posted by DaleClark
Actually, the lower one-wire sensor is the fan thermoswitch. It grounds out at a certain temperature to kick the fans on.
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
wire
Thanks, you know the color of the wire plug at this place?
I am not sure if it's black with red line.
I am not sure if it's black with red line.
Originally Posted by DaleClark
Actually, the lower one-wire sensor is the fan thermoswitch. It grounds out at a certain temperature to kick the fans on.
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
The two-wire sensor above it is the thermosensor for the ECU. It reports the coolant temp to the ECU for determining fuel amount and timing - it's a pretty primary input to the ECU. When the engine is cold, fuel doesn't atomize as well so the ECU richens up the mixture for the car to run properly.
The thermoswitch is commonly replaced with a lower-temp switch. The thermoswitch for the '89-91 RX-7 comes on at 95 deg. C instead of 108 deg. C, keeping the car in a better temperature range.
Dale
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White is tight
Joined: Sep 2002
Posts: 1,208
Likes: 0
From: Tucson, AZ
I had a hard time figuring out which plug was which because on the old threads people say confliting info. Some people say that the top plug is the fan switch and some said thermo sensor. I replaced the top plug which was the thermo sensor. So from here on out
Top plug.........Thermo sensor
Bottom plug.......Fan thermo switch
Lets please try to stop the conflicting info, if you don't know the correct answer please don't just guess at it.
Top plug.........Thermo sensor
Bottom plug.......Fan thermo switch
Lets please try to stop the conflicting info, if you don't know the correct answer please don't just guess at it.
Quoting myself from an older post:
Forget my first message.
Originally Posted by Mahjik
widebody2,
You just need the two sensors from the back of the housing?
If so, the top is the thermosensor and the bottom is the thermoswitch. You can get both from Mazda. The thermoswitch is the one people replace with the Miata part to turn the fans on earlier.
You just need the two sensors from the back of the housing?
If so, the top is the thermosensor and the bottom is the thermoswitch. You can get both from Mazda. The thermoswitch is the one people replace with the Miata part to turn the fans on earlier.
White is tight
Joined: Sep 2002
Posts: 1,208
Likes: 0
From: Tucson, AZ
Originally Posted by Mahjik
Quoting myself from an older post:
Forget my first message.
Forget my first message.
Originally Posted by the_glass_man
So where should you mount these if you don't have a water pump housing anymore?
If you have no water pump housing, it needs to be a similar location - on the engine side of the thermostat. That's the best place for a temp reading.
Dale
Originally Posted by DaleClark
Wow - that's a scary thought!
If you have no water pump housing, it needs to be a similar location - on the engine side of the thermostat. That's the best place for a temp reading.
Dale
If you have no water pump housing, it needs to be a similar location - on the engine side of the thermostat. That's the best place for a temp reading.
Dale
Last edited by the_glass_man; Mar 6, 2005 at 10:07 PM.
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