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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
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car runs like poo....help me!

  • Thread starter Thread starter ECU5.0
  • Start date Start date Aug 15, 2004
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jrichker

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Dublin GA
Aug 16, 2004
#21
  • Aug 16, 2004
  • #21
The code 21 is ECT which affects the A/F ratio & can have a major effect on performance

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 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

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
 

jwzg

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Apr 6, 2004
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Prattville, AL
Aug 16, 2004
#22
  • Aug 16, 2004
  • #22
Check your engine harness. Do you have the 10-pin connectors installed that were part of a factory recall? With all of those codes, I don't think you have that many sensors going at one time. Also, check your vaccum harness on the passenger side to see if it has been unplugged.
 

ECU5.0

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Jan 10, 2004
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raleigh, nc
Aug 16, 2004
#23
  • Aug 16, 2004
  • #23
oh yeah....the code 21 got thrown because i forgot to let the car warm up before i ran the test. how do i know if it has the recall on the connectors?
 

HISSIN50

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Nov 29, 1999
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Aug 16, 2004
#24
  • Aug 16, 2004
  • #24
wasnt the recall simply to extend the harness on the 10 pin harnesses? guys have had them and actually removed them cuz they werent helping with anything (not about to rip wires out), but it was thought the extra connectors were causing problems.
 

ECU5.0

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Jan 10, 2004
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Aug 16, 2004
#25
  • Aug 16, 2004
  • #25
alright, im starting to think that i screwed something up when i fixed my lower intake oil leak. well not necessarily screwed something up, just didnt do it right. i torqued the lower intake to 15 ft/lbs which i later realized wasnt enough....does anyone think that would cause a problem? im not loosing a coolant or oil and the car idles fine, but could a small vacuum leak still be present
 

Michael Yount

Mustang Master
Apr 10, 2002
9,039
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Charlotte, NC
Aug 17, 2004
#26
  • Aug 17, 2004
  • #26
Well - you can always add a little more torque - but I don't go much higher than you did -- 16-18 ft-lbs. Yes, you can have a vacuum leak at the lower - but you'd probably be losing coolant as well.
 

ECU5.0

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Jan 10, 2004
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Aug 17, 2004
#27
  • Aug 17, 2004
  • #27
alright, yeah i didnt think that i had a leak since i cant tell if its loosing coolant, which im pretty sure that it isnt, since there is no smoke and the level in the radiator and resevoir hasnt changed
 
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