didn't go back to check --- did you change ects n connector? Source from GM dealer. The connector is expensive. just do it

 

Not yet. It is on my list of things to do. Why do you ask?

 

Probably because the ECTS can also have an effect on the way the trans shifts.

 

You mentioned crappy fuel efficiency, and it MURDERS your MPG when it fails, usually causing the car to run obscenely rich (as though coolant is at -40 ---ALL THE TIME).

One of the 1st things to change on any "new to you" Saturn S series.
Original resin tip design failed in all cars; replacement is brass. Aftermarket ects's have calibration issues so go OEM on this. Connector is OEM only and should be replaced as ects failure almost always accompanied by coolant leakage onto connector terminals and subsequent corrosion. It does not take much to hose connection to the PCM and provide garbage readings.

The other big thing is the front O2 sensor, as it also of course affects air/fuel mix. If the car has been burning alot of oil and/or the car has been running super rich indefinitely, you may just want to swap in a new front O2 so you start from a known point with that.

I recommend the non-OEM Denso O2 sensor that is the same part number as the OEM sensor -- it's the same exact sensor but without the 100% dealership markup. Easily found and procured through Rockauto
I have tried bosch and my s cars hate them

 

A Denso O2 sensor is actually on my list of things to replace. I did not know about the defect with the original sensors for the temp. So there is both a coolant temperature sensor that controls the engine and another that controls the gauge?

 

oops forgot you have a 1st gen like me.

Yes there are two temp sensors:

a)two wire sensor that the PCM keys off of for coolant temp readings. This is the one you want to replace. Connector is a squeeze connector. Located on driver's side in the head.

b)single wire connector that drives the dash gauge.

If your signature would stop being so flaky (as discussed this is not your fault) and I would stop being so flaky.......

ALSO: The PCM uses the inferred coolant temp to determine when to turn on the aux cooling fan behind the radiator. If it thinks coolant is at -40, it's never going to tun on, and you may overheat on a hot summer day sitting in traffic. The other way to get that fan to come on is to engage the A/C; so although it sounds counterintuitive, cycle the AC on and off to keep the coolant temp down if the gauge starts getting near the red

 

As mentioned in another post, the fan turns on normally at the right time. The fan has never failed to turn on when the gauge was nearing red, preventing it from ever reaching the red zone.

Considering that, can replacing the sensor improve my fuel economy even though it activates the fan normally?

 

hmmmmmm

I would still replace it and the connector with the updated brass design for the sake of durability and the fact that you don't know when GM will run out of their stock......
might be used in other gm vehicles ---don't know

 

Where exactly do I get the genuine brand new GM good ECTS with the brass design? I want to make sure what I buy is not going to suffer from the problem again. All of them look brass on Rockauto for the two wire.

 

Go to a Saturn friendly GM dealership. Total cost for the two will be around fifty bucks or so.