[dr.gonzo!]

KOEO was 1-1 all pass

KOER I get

21- ECT out of self test range 0.3 to 3.7 volts.

94-Thermactor Air Injection system inoperative (I knew this one, no smog pump)

44-Thermactor Air Injection system inoperative (Right side duh).

33-EGR valve opening not detected.


The only one I haven't noticed before was code 21 any one know what thats about?

[1slo5.0]

Originally Posted by dr.gonzo KOEO was 1-1 all pass KOER I get 21- ECT out of self test range 0.3 to 3.7 volts. 94-Thermactor Air Injection system inoperative (I knew this one, no smog pump) 44-Thermactor Air Injection system inoperative (Right side duh). 33-EGR valve opening not detected. The only one I haven't noticed before was code 21 any one know what thats about?

Maybe the sensor has failed? Google a test for it. It should be x number of volts cold and then x number of volts when the engine is warmed up.

[dr.gonzo!]

I have seen 0.3 to 3.7 volts but on another mustang site I found 5 volts for hot. That and I didnt even know where on the car I should test the voltage.

[dr.gonzo!]

I have no idea how to use a volt meter but I used this page

Bad ECT sensor causing this problem or what??? - Mustang Forums at StangNet

and on the ohms part for pin # 7 and #35 on the ecc cable read 18 ohms with the multimeter set at rx100 so 18 x 100 = 1800?

[1slo5.0]

Originally Posted by dr.gonzo I have seen 0.3 to 3.7 volts but on another mustang site I found 5 volts for hot. That and I didnt even know where on the car I should test the voltage.

Originally Posted by dr.gonzo I have no idea how to use a volt meter but I used this page Bad ECT sensor causing this problem or what??? - Mustang Forums at StangNet and on the ohms part for pin # 7 and #35 on the ecc cable read 18 ohms with the multimeter set at rx100 so 18 x 100 = 1800?

This sums it up right here:

" A bad ECT will set a code 21 or 54. Engines with faulty ECT's may have hot starting problems because too much fuel is supplied during cranking.

Code 21 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error.

The ECT sensor has absolutely nothing to do with the temperature gauge. They are different animals. The ECT sensor is normally located it the RH front of the engine in the water feed tubes for the heater.

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Voltages may be measured across the ECT/ACT by probing the connector from the rear. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms"

[dr.gonzo!]

Yeah Im not getting any voltage at all on pin #7 and #25 I have the volt meter set to dvc 12 and poked around and some others shot up to 12 but not even a budge on #7 and #25. Is there a fuse or something that would make both of them not read anything at all?

I am using this as my guide If that helps

[Mustang RacR94]

normal operating range for a ECT is usually around .5 volt to 4.5 volts, usually means if its getting two low of a reading the sensor is either bad or there is unwanted resistance in a wire going to or from the sensor, to high is either the sensor or a short to ground

[Mustang RacR94]

btw thats the engine coolant temp sensor if you didnt know

[1slo5.0]

Originally Posted by dr.gonzo Yeah Im not getting any voltage at all on pin #7 and #25 I have the volt meter set to dvc 12 and poked around and some others shot up to 12 but not even a budge on #7 and #25. Is there a fuse or something that would make both of them not read anything at all? I am using this as my guide If that helps

I believe pin #7 is the output from the ECT. Is there voltage at pin #46? I believe pin #46 is the source voltage for most of the sensors. The other wire (pin #7) would be the return signal to the computer telling it what the conditions are. If you have voltage at pin #46 (5 volts I believe) and nothing at pin #7 than you have a broken wire or a bad sensor. You can check voltage directly at the sensor to determine if the sensor is bad or if its a broken wire. If there is no voltage from the yellow/green wire at the sensor then the sensor is bad but if there is voltage there then you need to follow the signal wire to find out where the voltage disapears. If there is no power at pin #46 it is likely that you have a bad computer. I doubt this is the problem though because you would also have codes 22, 23, 24 and 31.

[dr.gonzo!]

Yeah thats another can of worms I found out today. I took the ecc out and it had duct tape over the "void if tampered" sticker.

[1slo5.0]

Originally Posted by dr.gonzo Yeah thats another can of worms I found out today. I took the ecc out and it had duct tape over the "void if tampered" sticker.

Probably had a chip in it at one time. I've seen alot of them duct taped over the chip or over the whole after the chip was removed.

[dr.gonzo!]

I think it was the connection at the sensor because when I unplugged it, it had really thick gunk in it. (picture gum left out in the sun) I doubt it was dielectric grease but if it was...it had seen better days.