I am working on my 81 RX-7. I have been up and down and left and right and all around these forums and everyone calls different sensors by different names. I feel like a deer in the headlights sometimes. I am looking for the sensor that control the choke magnet. I believe its the one in the back, upper side of the water pump (below is a picture of the sensor taken out and cleaned up). However this sensor is around $70 to replace and want to make sure its the right one. When I looked for it online i found it under the name "Engine Coolant Fan Temperature Switch" So just confirming, Is this the Sensor i want to replace?

 

It's the correct one. The wires brake really easy so be especially careful. They can be fixed with a little skill though.

 

I dont believe the wires are broken, I'm pretty sure the sensor is bad, it happened when i was working on the heat hazard sensor, accidentally grounded the plug on the same circuit. Heard the choke pull in instantly.

 

Here is the procedure fromthe factory service manual to testing this. Page 4A-32 http://www.foxed.ca/rx7manual/manual...ssions_12A.pdf

 

i think i have one or two of those that i'm not using if you need one.

 

Check the fuse in the ECU next to your left foot.

 

Well i have some news to share, for those who care....(didn't mean to make that rhyme). Anyways, As far as the sensor is concerned i reread my Haynes last night and noticed i made an error. I thought I read if continuity exists above 168 degrees Fahrenheit, the sensor is good. Its actually if continuity CEASES to exist above 168 Degrees Fahrenheit.....so i dangled it in a pot of water and measured the temp with a laser thermometer, The sensor is working fine. However I just went out and checked the ECU fuse mentioned by NCross (I just put a new ECU in a week ago and the fuse was fine) The fuse was indeed Broken. So now instead of paying $70 for a new sensor im paying 70 CENTS for a new fuse. Thanks for the help guys, really appreciate it.

 

I just had the same problem with mine is how I knew the answer

 

I have another question for you NCross. My father claims that its not the right fuse in it (he drives a 74 datsun Z). He says he has never seen a 250V5A automotive fuse, So my question to you is, What is your fuse rated too and or do you know the correct fuse rating?

 

Nice catch!! my choke stays out for all of maybe 30 sec on cold start - assumed the $$$ sensor was the prob too. Would be nice if this little fuse is the bastid....


Stu Aull
80GS
Alaska

 

Sounds more like the ECU is the problem. If the fuse was bad the choke would not stay out at all. It would retract as if the magnet never energized (because it didnt).

 

I wonder if the water temp sensor i was about to replace would be your problem? if it was going bad and not activating early, that could do it....not sure if its possible for the sensor to do that though. what does it do to your idle after the 30 seconds and it pulls in? does the car die? or does it idle fine after that?