Coolant Temperature Sensor

[FineWine]

I'm 95% positive I'm correct, but the temperature guage on the dash cluster is linked to the coolant temperature sensor near the disty cap where the coolant bypass is, correct?

I just finished my swap, and I'm trying to make sure the thermostat and everything is working correctly. I feel like the temperature isn't reading correctly though, because the valve cover is feels hot, but the guage isn't moving.

[93 Pro]

The sensor in the thermostat housing is to kick your radiator fan on if thats the one you're talking about.

[MD323]

I'm 95% positive I'm correct, but the temperature guage on the dash cluster is linked to the coolant temperature sensor near the disty cap where the coolant bypass is, correct?

I just finished my swap, and I'm trying to make sure the thermostat and everything is working correctly. I feel like the temperature isn't reading correctly though, because the valve cover is feels hot, but the guage isn't moving.

there is two, one with 2 wires(the engine listens to this one) and the single wire one for the dash

[therieldeal]

what did the motor come out of and what kinda car do you have?

the ford and mazda senders for the gauge are different. its the tiny 1 wire one on the front corner of the head below the distributor.

[FineWine]

It came out of a tracer. What does this mean for me?

[protégébob]

you need to get the mazda spec sensor, do you still have the B8 (1.8 SOHC), it might have the correct sensor.

edit:
after a quick check on rockauto.com the sensor from your B8 would work.

[therieldeal]

indeed it would . i had to do the opposite swap when i put the GTR motor in my escort. i might still have the GTR sensor somewhere, if you already ditched your old motor.

[jasoncsprotege]

Mazda had 3 temp sensor wires in a DOHC 1.8. 1 for the ECU, 1 for the cooling fan, and 1 for the temp gauge. The ECU 1 is (normally) a green topped sensor 2 pinned, thje electric cooling fan sensor is a 1 pin but located in the thermostat housing, and the gauge temp sensor is a single (spade style) connector located in the front of the head kindof next to the exhaust manifold.
hope this helps any,
Jason

[luckycharms]

what did the motor come out of and what kinda car do you have?

the ford and mazda senders for the gauge are different. its the tiny 1 wire one on the front corner of the head below the distributor.

yeah on ma gtx i have a wiring harness of a escort and i ahve make a bypass for the fan

[FineWine]

ok, working on this right now and needs some clarification:

the engine AND harness came out of the same Tracer
the car is a protege DX.

do I still need to swap the sensors?

I just discovered that there are two spade
style connectors near the coolant housing, and there are two sets of wires that connect to it from the ECU harness. 1 is a single wire, one is a two wire. I currently have the two wire on the connector thats right where the clip connector on the coolany housing is. The other one wire I discovered I forgot to connect... I'm assuming this one goes to the connector in front of the head. Is this correct, or do I Need to flop them?


BTW, I just let the car run for about 5-10 minutes. I left the radiator cap off and filled the radiator to the top. a few minutes in I could see the fluid start to "pulsate", so the water pump is definitely pumping and the thermostat is (apparently) opening. BUT, the heat never worked. My heat worked before the swap, though. Since the guage still isn't working (We'll see if I fix it here in a sec), I shut the car off because the engine was getting hot and it had that "overheating smell". The fan never came on either.

Am I just being a scaredy cat, or should I let the car run a little longer? IT's about 40-50 degrees here right now, so I expect it to take a bit to heat up.

[90prtege]

correct plug that one wire into your sensor on the front of the head. when you first start a front wheel drive vehicle you need 2 purge the air from your system easy way to do it is a add coolant till its full. start run it until you know the thermo stat has opened normally 5 - 10 min during that time also have your heater on full speed fan, max heat, and defrost so it purges the heater core also after first start shut it down and add more 50-50 mix. you will probably need about 1/2 gallon or 2 liters what ever measuring system u use. most of the time when you have no heat in a heater after a install its because of a trapped air bubble in one of the tanks. but also you have `to have the heater lines correctly installed and not reversed the coolant in the tanks (rad and heater core) is only meant to travel one way for correct cooling. to test and make sure your fan on rad is correctly working unplug the sensor on the thermostat cover and ground the wire with some kind of probe. your fan should stay on when its grounded. your fan should turn on and off in about 1 - 3 min intervals once car is completely warmed up and sitting idling. when your car is moving you should have enough force of air threw the rad that it doesn't function much @ all.


edit: also if your fan is running the whole time while your trying to warm it up you will have about a 30 min wait before it warms up fully because the stock elec fan on these cars works to well and over cools best bet i would say is disable your fan until you know that the thermo stat has opened fully. i know on my EGT i did a complete rad flush and i couldnt get the darn thermostat to open until i disabled the cooling fan from running full time (idiot before me wired it 2 run when ever car was running)

[FineWine]

ok, so my dash guage is working now. The car is overheating, but from my tests above (pull the cap, fill it up, and watch for movement in the fluid after a few minutes), the thermostat is opening. I'm still not getting heat though. It IS possible that I swapped the hoses though.

Would swapping the heater core hoses cause it to overheat?


Also, this didn't happen before...but now whenever I'm revving over 2.5k there's a hesitation...almost like a complete spark/fuel cut.

[90prtege]

it could still have a air bubble in it im not sure if it would cause it 2 over heat but if the coolant cant get moving thru the system its possible. hesitation . basics to check is plugs wires cap rotor fuel filter fuel supply timing on dist and timing belt, firing order and emissions componites just 2 name a few items i know helps bring down the options i would first check all spark related items first they are normally the cause of most hesitation problems . *bright light just went off* is your cat plugged? a plugged cat could cause overheating and hesitation. just trying to search ideas i can find if anyone else has ideas id love to hear them also for future diagnosing

[FineWine]

remember that the engine was not doing this on previous "test runs". It just started doing that last night. I haven't even put any miles on it yet (since the swap).

Another question:

behind the engine, on the block, between the oil filter and starter (right under the support for the starter) there's some sort of sensor with a spade connector. It had a short (4" or so) 1 wire with female spade connections on both ends (looked like an extension or something). A yellow wire with red strip. I could not find anything that looked like it plugged in to the "extension", but there was a compatible wire and connector on the harness right there in that position. So, I removed the "extension" and plugged that wire in there.

Any clue what this sensor is, and if I plugged the right wire in?

[90prtege]

that is the oil pressure sending unit and yes that wire is yellow with a red stripe