ACT sensor, to be or not to be?
- Thread starter LaserSVT
- Start date
I would suggest you keep it or get a replacment. When an act sensor brakes or gets all gummed up it cant measure the incoming air temp properly. You get hessitation and bogging of the car and it could die. I think it sends the temp to the ECM for proper fuel enrichment. It will make the fuel rich or lean depending on the air temp. So i say keep it. "please sombody correct me if im wrong about the rich or lean part" 
The car did not have one when I bought it. I have the Typhoon intake and it looks like the sensor hole is relocated to the spot just after the EGR spacer facing foreward on the upper plenum, does anyone know if this is correct?
Ford didn't install useless sensors.
ACT can cause that, but you need to pull the codes to check for other conditions.
I have no experience with your manifold, but you need to mount the ACT in the airstream. If you can get it in the intake manifold, great.
If you can't get it in the intake, then look to mount it in the inlet tube between the MAF/TB. If that won't work, then drill a hole in the intake air filter box...
jason
Here is a discussion I wrote up on moving the ACT from the intake manifold to the air filter box...
http://www.freewebs.com/vristang/eecivfaqs.htm
If you have questions, feel free to ask...
Thumbing through the TwEECer (CalEdit) this is what can be seen...
In the X3Z Calibration
FN 825B - ACT will increase the engine idle rpm after about 192F, maxing out at 64rpm by 208F
FN 220 - EGR Multiplier is 0 until 58F, maxes out at 1 by 60F
FN 126 - Spark advance starts to retard at 160F maxing out at -2* by 190F
FN 135 - WOT spark advance is retarded starting at 150F, maxing out at -6* by 240F
FN 300 - Open Loop Fuel Multiplier is unaffected by ACT (always 1)
SCALAR - ACT MUST be between 100F and 200F for the Adaptive Strategy to start learning
In the A9L Calibration
FN 825B - ACT will increase the engine rpm by 48rpm at 200F, and a max of 72rpm at 226F
EGR Multiplier is .8 until 0F, then rises to a max of 1 by 56F
FN 126 - Spark advance starts to retard at 160F maxing out at -2* at 190F
FN 135 - WOT spark advance is retarded starting at 150F, maxing out at -6* by 240F
FN 300 - Open Loop Fuel Multiplier is .64 until -40F, .81 by 0F, and maxes out at 1 by 76F
SCALAR - ACT MUST be between 100F and 200F for the Adaptive Strategy to start learning
So what does this mean?
Idle speed – Obviously for both calibrations the affect is going to be minimal, assuming all other idle contributors are working properly. Moving the ACT to a cooler location should not have a major impact on idle speed.
EGR – Moving the ACT to a cooler location will affect the function of the EGR. It would not be recommended to try and pass an emissions test with the ACT in the airbox on a cold day (below 60F).
Spark – The Spark Advance is RETARDED with higher temps. Moving the ACT to the airbox can help to keep ignition timing higher. However, keep in mind that Ford used the ACT as a ‘Safety Factor’ for preventing high temp detonation. False information to the EEC-IV will make detonation more likely when the engine is warm/hot.
Fuel Multiplier – The Fuel Multiplier increases with higher ACT temps. Due to the low temps at which the ACT will impact the Fuel Multiplier this is not likely to cause an issue.
Adaptive Strategy – This may be the most critical one for most daily driver Mustangs. Not allowing the Adaptive Control to function (because the ACT never sees 100F in the airbox), could hurt fuel economy and could cause drivability issues.
http://www.freewebs.com/vristang/eecivfaqs.htm
If you have questions, feel free to ask...
Thumbing through the TwEECer (CalEdit) this is what can be seen...
In the X3Z Calibration
FN 825B - ACT will increase the engine idle rpm after about 192F, maxing out at 64rpm by 208F
FN 220 - EGR Multiplier is 0 until 58F, maxes out at 1 by 60F
FN 126 - Spark advance starts to retard at 160F maxing out at -2* by 190F
FN 135 - WOT spark advance is retarded starting at 150F, maxing out at -6* by 240F
FN 300 - Open Loop Fuel Multiplier is unaffected by ACT (always 1)
SCALAR - ACT MUST be between 100F and 200F for the Adaptive Strategy to start learning
In the A9L Calibration
FN 825B - ACT will increase the engine rpm by 48rpm at 200F, and a max of 72rpm at 226F
EGR Multiplier is .8 until 0F, then rises to a max of 1 by 56F
FN 126 - Spark advance starts to retard at 160F maxing out at -2* at 190F
FN 135 - WOT spark advance is retarded starting at 150F, maxing out at -6* by 240F
FN 300 - Open Loop Fuel Multiplier is .64 until -40F, .81 by 0F, and maxes out at 1 by 76F
SCALAR - ACT MUST be between 100F and 200F for the Adaptive Strategy to start learning
So what does this mean?
Idle speed – Obviously for both calibrations the affect is going to be minimal, assuming all other idle contributors are working properly. Moving the ACT to a cooler location should not have a major impact on idle speed.
EGR – Moving the ACT to a cooler location will affect the function of the EGR. It would not be recommended to try and pass an emissions test with the ACT in the airbox on a cold day (below 60F).
Spark – The Spark Advance is RETARDED with higher temps. Moving the ACT to the airbox can help to keep ignition timing higher. However, keep in mind that Ford used the ACT as a ‘Safety Factor’ for preventing high temp detonation. False information to the EEC-IV will make detonation more likely when the engine is warm/hot.
Fuel Multiplier – The Fuel Multiplier increases with higher ACT temps. Due to the low temps at which the ACT will impact the Fuel Multiplier this is not likely to cause an issue.
Adaptive Strategy – This may be the most critical one for most daily driver Mustangs. Not allowing the Adaptive Control to function (because the ACT never sees 100F in the airbox), could hurt fuel economy and could cause drivability issues.
Grabbin' Asphalt
10 Year Member
Good info here in this old thread, ...just got code #54, ..cleared it and it came back, ....more money to sensors fund lol
Code 54 – ACT sensor out of range. Broken or damaged wiring, bad ACT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ACT can be in error.
Check the resistance of the black/white wire to battery ground. If it is less than 2 ohms, it is good. If it is more than 2 ohms, the black/white wire has bad connections or a broken wire. Always take resistance measurements with the circuit powered off.
See the graphic for the 10 pin connector circuit layout.
Then check the resistance of the ACT sender located in the #5 intake runner on most 5.0 stangs.
ACT & ECT test data:
The ACT & ECT have the same thermistor, so the table values are the same
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. 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
Check the resistance of the black/white wire to battery ground. If it is less than 2 ohms, it is good. If it is more than 2 ohms, the black/white wire has bad connections or a broken wire. Always take resistance measurements with the circuit powered off.
See the graphic for the 10 pin connector circuit layout.
Then check the resistance of the ACT sender located in the #5 intake runner on most 5.0 stangs.
ACT & ECT test data:
The ACT & ECT have the same thermistor, so the table values are the same
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. 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
Grabbin' Asphalt
10 Year Member
Replaced gunky old one, idles very smooth now, cleared codes, system pass #11 ...back to normal operation.
