I just bought my first rx7 and I am a bit of a newb. The car is not running now because it needs a fuel pump but I did have it running for a minute off a hand pump fuel pump. I am trying to get a few things straight. Now I have heard there is a Water temperature sensor that controls high idle (3000 rpm) when the engine is cold, and then once the engine is warm it tells the ECU to kick down the idle.

Now where is this sensor? Is it in the back of the water pump?

The car hasnt be on the road for a while and the previous owner was unsure of the cause of the problem but he said the car would run warm (or a little hot) and there was some sort of "heat sensor" that was causing high idle all the time and the car would run warm. This guy is no mechanic, and doesnt know much about cars but I assume a mechanic told him of this.

Could this be a faulty Water Temp Sensor?

In the following picture, Is this the water temp sensor? (back of water pump)

Thank you all for your help, much appreciated!

 

The #2 water temp sender, which is on the rear of the water pump, is used to determine when the choke-hold magnet should let the choke retract during warm-up.

It doesn't effect idle in other ways, and as far as I know has no influence when the choke is not activated.

What year and model is your -7? Engine control varied quite a bit during the 7 production years of first-gens.

 

Its a 1985. 12a. 5spd. When The choke inside the vehicle is pulled the metal flap on the carburator doesnt move. I actually cant move it by hand at all, like its either frozen or its not suppose to move at all. I dont know if this would have an affect on it.

What else would cause a high idle? and causing it to run warm other than, thermostat, low coolant, water pump, clogged or bad radiator/hoses.

I also havnt had the car running for longer than a minute and I guess I should really get it going before I jump to far ahead. When i did have it running it was at like 3000 rpm and ran solid! which is a good sign

Thanks man!

 

Unless the choke/carb has been modified, the choke butterfly should definitely close when you pull the choke ****.

High idle is most commonly caused by a vacuum leak. There's a dozen things that can cause it, though. not enough info to go on.

Can you post some pics of your carb and linkage? Do you know if there've been any mods to the carb?

Start-up idle with a fully-pulled choke can run as high as 3k, more commonly 2500 or so. But if your choke isn't closing, something's wrong.

Not running for more than 30 secs also shows something's not right.

If it only runs for 30 secs, how do you know it running warm?

 

Well the fuel pump is shot and I used a hand pump and 5 gallon tank to get it running for about a minute. I need to drop and clean the tank and install the new fuel pump to get it running on its own. I will post pictures of the carb, the carb is more than likely not modded b.c the previous owner (My girlfriends uncle) is the original owner and doesnt know anything about fixing or modifying cars, just knows when to do basic maitence.

So I really dont have enough data from the car running just that the PO said somthing about high idle + running warm and a heat sensor was the cause and never got around to it. The car has been off the road since 1999 and was last started 3 years ago. And im curious if this sensor going back could cause this. I dont even know how the car is going to be, maybe this problem is even there.

Thank you very much for your help or any input btw

 

that sensor is just a switch which when the engine is cold allows the magnet in the choke in the dash to be ON and the choke **** will stay out. once the engine is over whatever temp (off the top i'd say 65c), the switch opens and the choke **** will pop in.

i would replace the fuel pump, filters, and then proceed to do the idle mixture and basic tune up stuff.

there is a page in the manual, and the manual is here www.foxed.ca