ECTS showing 20*F below ambient at startup
 

Since adding the scanguage to my car, I've noticed it ALWAYS reports CLOSED LOOP, perhaps this is the default setting because my car doesn't report this info, I'm not sure... but what I've noticed is say the ambient temp is 80*F, my coolant temp per the ScanGauge will show 60*F. If it's 65*F outside, coolant temp will show 45*F.

Does this sound like the coolant temp sensor (ECTS) is failing or is inaccurate? I've replaced the sensor twice before and the electrical connector has also been replaced. This is a common problem w/ Saturn's.

I'm wondering this also because I installed a new thermostat a month or so ago, and since then, the scangauge only shows roughly 170*F after warmup on a hot day, the dash needle isn't halfway, it's basically reading the same thing. I was going to replace the thermostat, but I'm wondering if the ECTS is at fault. Coolant has been flushed about 12k ago, and is clean and free of gunk.

I also never hear the fan turn on, but will cycle if A/C is used.

So it's like 4 problem all related to one another. :rolleyes:

The coolant temp could just be an OBD calibration issue, or it could be as you fear.

My VW only goes to open loop for a few seconds after a cold start, and during DFCO. Is the SL2 equipped with a wideband O2 sensor?

did you replace the correct coolant sensor? I think some cars have one sensor for the computer(that would give you a reading on your scanguage) and one sensor for the guage on the instrument cluster.

you are correct. OBD-II saturns have one sensore for the computer (two wires) and one for the guage (one wire). i know if you go to the dealership and ask for an ects, they will give you the two wire one. its the same part number for all s series saturns.

Looks like you guys got me on this one... I replaced the two wire sensor which is prone to issues. It's on the driver's side of the head just below the EGR.... where is this other one? I thought I knew this car inside and out.... apparently not!

Never heard of it.

Do you have a Haynes or other shop manual?

I remember on my '93 SL2 there were 2 temp sensors, and can remember replacing both of them.

One was on the block. Having a senior moment...can't recall where the other one was.

I didnt know scangauge would work with an obd1

The 2-wire temp sensor should be as accurate as possible, the 1 wire sending unit is not so important

you replaced the stat with what ? find the stat's opening temp by pulling it off the car and checking it in a pan of hot water. (also the sensor) Compare those results with what Saturn says the engione needs. Todays cars use higher temp stats...
A stuck open stat will cause low temps. Make sure it opens and closes and is intalled correctly

His Saturn is a 1996.

The new stat is a Napa part rated at factory temp. ECTS is also Napa sold as OE replacement.

correction on my previouse post. it was the OBD-I saturns that have two sensors. i just looked in the haynes. i had my information backwards.

and as for using aftermarket sensors, i will tell you first hand its not a good idea. i had a 1993 Sc2 for 4 years and had nothing but problems with the sensors from anywhere but the dealership. however, if you are too far from a dealership to make the trip. (the part is only about $5, so more that a few miles isn't worth it, IMO) male sure that the sensor is make of brass and not the resin type.