sammy1

Jusyt wanted to drop a line in the hopes that it will help anyone with the same problem. 1988 GTU no mods

Problems observed when car acted up:

1. car stumbles and bucked (barely runs, low and erratic idle)
2. black smoke coming out of tailpipe
3. felt like the car was misfiring (extreme loss of power)
4. turning car off for a few minutes was only temporary relief
5. ran fine the next day, like nothing happened
6. Carbon buildup on plugs
7.Worsens as time goes by
8. Engine diagnose did not catch it

This problem has plagued me for 1 1/2 years and my reluctance to take in to the dealer has payed off huge.

Thanks to this forum and a little digging, the problem was traced

to the water thermo sensor (on back of water pump).

Since ordering from Mazdatrix($51.00), the car has ran perfect for over two weeks and I am the most happy RX7 owner in America. I love this car again and it will not be traded in for more "practical transportation".

Thanks to all who helped lead me to the right path and this forum is checked daily and is an awesome place to gain info on a great car.

jacobcartmill

iTrader: (6)

that is exactly what my car is doing dude...

riptyde

iTrader: (5)

My car has the same characteristics, except it doesn't have extreme lose of power. When I rebuilt the engine the engine wouldn't start, so I went down the list of possilbe causes and came to the water thermo sensor and I unplugged it because it has a fail safe mode and my car started, but I still have some of the same characteristics. Do you think it could still be the water thermo sensor even though it's unplugged?

HAILERS

riptyde
Rotorite...................You NEED to have a water thermo sensor. No ifs ands or butts.

riptyde

iTrader: (5)

HAILERS
The water thermo sensor is in the back of the water pump housing and it is disconnected and it runs. Now if you want to be an *** about it then prove me wrong because I know its unplugged on my car and the car is running. Why don't you try to unplug it on your car and see what happens.

jacobcartmill

iTrader: (6)

i think he meant for practical use dude. an fc should always run better with this sensor functioning correctly. dont be talkin smack, HAILERS rules

jacobcartmill

iTrader: (6)

well, i replaced that coolant temp sensor (on the back of the water pump elbow, by the alternator...) didnt do ****.
the plug just totally pulled off of the old sensor and the wires practically pulled right out of the plastic plug part. i will go back and check for resistance on the two wires.

Six Rotors

iTrader: (17)

Of course the car will run with that water thermosensor disconnected----the ecu sees that as a sensor failure and goes to a preset failsafe of 80C(thats 176F to you people).Now since you live in sunny California this is no big deal.If you lived in Ohio it is more of a problem.
Even more important is the fact that if you leave the sensor connected,and sensor is off the ecu can become totally confused about the coolant temperature.Since the range of correction to fuel quantity injected for coolant temperature ranges from PLUS 60% at -20C to 0 at 80C you can see there is lots of scope for lousy running and or no running!

HAILERS

Never said the car would not run without the water thermo sensor disconnected. Nowhere in any post on this or any other forum have I said anything of the kind. But I repeat...you need to have the water thermo sensor connected. No ifs, ands or buts. The car will run without the tps, pressure sensor,secondary fuel injectors, oil injectors, trail coil assy disconnected, water temp switch, any of the emissions solenoids disconnected. But you NEED to have them connnected for the car to run as designed(right).

jacobcartmill

iTrader: (6)

so what are you trying to say? its like 60 degrees out today and i replaced my sensor and it didnt do ****. what does this mean.

cmanasseri

I'm so glad I searched and found this old thread, turned out the problem I've been having all winter was a bad water thermo sensor connector - took it off, cleaned it and put some conductive grease on it and the car runs better than it has in a long, long time.

Chuck

HAILERS

SixRotors stated the need for a water thermo sensor a lot better than I did in my post. It seems to me if you have an intermittant circuit to the water thermo sensor, that that would cause more of a problem than no sensor connection at all. Sort of like the circuit makes for a moment then the circuit gets broken by vibration. That would confuse a ECU big time. Much more than the sensor just not being connected.

But say its forty degrees outside and the thermo sensor is disconnected. That means the ECU assumes a 176 degree temp That car should some signs of being a bit of a dog.