2005 4.0l V6

I suspect my ECT (sensor for computer) is malfunctioning.
After a -3℉ overnight the engine started and ran roughly for 8 seconds before smoothing out to a reasonable idle. Fine.

I filled with 91 because I wanted to see what premium gas would do on a familiar, hilly, highway run.
The 16.3mpg monthly average was way below the >19mpg seen several times on this run.

After the 150 mi. home stretch (solid 65ph), I felt the catalyst putting out heat and a real, working smell (from the side of the truck, not the exhaust stream).
I smelled this on other vehicles before.

I searched a bunch and found a chart of ohm values for testing a ECT. Are these values representative of ours?

177 Ω @ 212℉ 100℃
241 Ω @ 194℉
332 Ω @ 176℉
467 Ω @ 158℉
667 Ω @ 140℉
973 Ω @ 122℉ 50℃
1188 Ω @ 113℉
1459 Ω @ 104℉ 40℃
1802 Ω @ 95℉
2238 Ω @ 86℉ 30℃
2796 Ω @ 77℉
3520 Ω @ 68℉ 20℃
4450 Ω @ 59℉
5670 Ω @ 50℉ 10℃
7280 Ω @ 41℉
9420 Ω @ 32℉ 0℃
12300 Ω @ 23℉ -5 ℃
16180 Ω @ 14℉
21450 Ω @ 5℉
28680 Ω @ -4℉ -20℃
52700 Ω @ -22℉ -30℃
100700 Ω @ -40℉ -40℃

Can the sensor be tested while still clipped into the black plastic housing?

These sensors do need to be in liquid (hot water bath) to be tested, yes?

 

Its actually the ECT sensor you want, engine coolant temp sensor, its a 5volt sensor

Yes, tip needs to be immersed in warm fluid for it to read temp, warm air doesn't work

Ford readings here: https://www.explorerforum.com/forums...art.24365/full

CTS might be coolant temp sender, which is 12volts and only used by Dash Board temp gauge, 2005 may or may not have that, it would be next to the ECT sensor on the top plate of thermostat housing, but Ford did eliminate this SENDER in mid-2000's, and had computer send dash board temp gauge correct level using ECT

There is also a CHT(cylinder head temp) sensor, these were only used on the 2001-2011 2.3l Duratec Rangers


ECT sensor has a cone shaped tip, 5volt
Sender has a cylinder shaped tip, 12volt
Not interchangeable

 

ECTs are more widely known to Control\Instrument Engineers+Technicians as 2WireBiMetalicThermoCouples.
Best way to confirm a good ECT, a 2PointRangeTest removed from the TStatHousing & Harness, with an OhmMeter,
first in a pot of 212f BoilingWater, then in a cup of 32f IceWater.
Also check that each Wire\Pin is not grounded\shorted to the case AKA ThermoWell.

 

both sensors are the same. can you get to the plugs to switch them around on the sensors?

 

The sensors are not the same.
Learned here the sensor for the engine management computer is 5 volts.
The other one is a sender for the dash gauge only and is 12 volts.
They are not the same.

 

Just replaced thermostat housing on my 2004 4.0 with original sensors and both are the same with same part numbers. As for the voltages I never checked it.