junaid

I've read a lot of posts on this issue so I have a resonable idea as to what the problem could be. But, being a novice, I'd like your opinions...

The engine coolant temperature (ECT) guage has been showing really low readings that last few days. It is below freezing where I stay, but the ECT guage shows almost min (as in close to zero!) on the highway and a little above min in the city. Once in a while, I also get a check light which goes away if I stop the car for a short time. I got the diagnosis code as 2312 (ECT Sensor). But I haven't been able to replace the sensor as yet since I had to make a trip over Thanksgiving (600 miles). All liquid levels seem fine. So, in all probability a new coolant temp sensor should fix this check light.

On the trip, I noticed that I got around 26.5 mpg with 91/93 oct fuel. I'd been using 87 oct fuel prior to this as I didn't know any better. But, curiously, my fuel consumption has remained unchanged. I'd assumed, based on some posts here, that I'd notice some increase in mpg with the proper fuel. Was my assumption incorrect, and if not, is there something I could do to get the expected boost?

My trip back is on Thursday (another 600 miles). I hope I'm not running rich because the ECU thinks I'm running cold (because of the faulty sensor). The car feels perfectly normal to drive. Do I need to worry about my cats getting affected on the return trip? Must I replace the ECT sensor before I start back?

Thanks for your time,
Junaid

Kris Hansen

so it will disregard the coolant temp sensor.

How is your heat? How about the guage?

Pizzawhlz

If gauge is registering a Temp it might be right the car is cold. When sensor is bad the Gauge shouldn't do anything. Does car blow heat?

junaid

The heat... I'm not freezing in the car, but it does not feel as warm as it should be with the heat on. The guage seems to be working since it does show a slight increase in temp when I'm running in stop and go traffic.

If I understand right, you're suggesting that I keep running when the MIL comes on?

junaid

The car does blow heat, but it does not feel warm enough. The guage does move... could it be that the sensor is failing? Or that its dirty/clogged? Is there some way for me to check if the thermostat is the problem?

Kris Hansen

Wait, so the heat is cold, and the guage is not normal? I'd agree with Pizzawhlz, sounds like tstat.

junaid

Thank you folks. Since it seems like replacing the thermostat would be an involved procedure, I'll get to it once I get back home. Hopefully, the car will be ok for the next couple of days and 600 miles!

junaid

While driving around town, I turned up the heat to HI using the climate control, and it got really warm. I'd never turned it up that high before. So, if the heat seems ok, does that rule out the thermostat as a problem?

Kris Hansen

Not necessarily.. what does the guage do? If you go on the highway, does the temp drop?

junaid

... and, as was observed earlier, the coolant temp guage stayed at zero on the highway. The heat came through fine though. The coolant temp guage creept up very slightly (just over the min mark) when I got back in town.