Charge Air Temp Sensor: what's inside of it??

[jonnymopar]

I figured it would just be a thermistor, but I can't get any ohm reading across mine. Now I'm wondering if my sensor is dead. Anybody know??

[NAJ]

ACT Sensor is a Thermistor,if Sensor is Open it should set a Code 23.

[jonnymopar]

Cool, I think I might just gently slice it open if it's dead anyway. Unfortunately, I don't have a car to try it on, so no check engine codes to go by.

I just wanted to compare the TII charge air temp sensor to a 1st generation Neon charge air temp sensor. The Neon sensor is a 10k thermistor. If the TII sensor is the same, I'll end up using the Neon sensor in my 2.4 swap.

[NAJ]

Diagnostic Flow Charts are practically the same between Neon 2.0 DOHC and T2,T4 ACT Sensor. Chrysler does not list Resistance Specs,ACT Sensor Response Chart is Temp = Voltage.

[jonnymopar]

Sweet! Is there anywhere I can get those charts?

[KitCarlson]

I am also working on this. I have a 84 Daytona engine and the original ACT terminals were giving me fits. I decided to us a GM sensor purchased from BMotorsports.

CONN-85555 GM Delphi / Packard IAT / MAT / ACT Sensor Connector Pigtail # 12102620 $5.99
SNSR-02057 Fast-Response GM Delphi / Packard Intake Air Temperature Sensor ( IAT / MAT / ACT ) or Manifold Air Temperature Sensor # 25036751 *Recommended* $14.99

I found Ballenger Motorsports - High Performance Electronics to be a good vendor (not associated with them)

Temperature C ACT sensor Ohms
0 8776
25 5455
100 644

You can find table data on their website.

I can help derive 2nd order polynomial fit for your application, I have a fit for 2K pull-up (to 5V) and 10 bit a/d

[KitCarlson]

I use thermocouple mounted to sensor and an ohm meter to measure sensor resistance. When a temperature chamber in not available use a freezer (or ice water), room temperature and boiling water. Three points is enough for a 2nd order curve fit. I then use the resistance and the pull-up value and supply voltage to calculate the voltage at each temperature. Next the a/d counts are figured then Excel is used to fit the data to a 2nd order polynomial used to convert a/d counts to temperature. If anyone needs more details please ask.

[jonnymopar]

I do have access to several environmental chambers at work. My original plan was to place the two sensors in a chamber and do a single temperature cycle (maybe -10C to 50C to -10C stepped 0.1C, or something like that). But, a dead sensor puts a damper on that one, dammit.

Anybody want to lend me one? I can't justify spending $50 for a sensor that I may not even use.

[NAJ]

ACT Sensor Response Chart ;
-20 F = 4.81 Volts
0 F = 4.70 Volts
20 F = 4.47 Volts
40 F = 4.11 Volts
60 F = 3.67 Volts
80 F = 3.08 Volts
100F = 2.51 Volts
120F = 1.97 Volts
140F = 1.52 Volts
160F = 1.15 Volts
180F = .86 Volts
200F = .65 Volts
220F = .48 Volts
240F = .35 Volts
260F = .28 Volts
Diagnostics on ACT Sensor Circuit
Check All Terminals for Damage,Push Out or Corrosion,Repair as Necassary
and Retest.
Disconnect Sensor Connector and Read Voltage(With Scan Tool or DVOM)
Is Voltage Reading above 4 Volts?
NO..... Disconect Engine Controller Connector and Check Resistance to
Ground on Both Ends of Signal Line,is Resistance Below 5 Ohms?
Yes : Repair Signal Line for Short to Ground.
No : Check Signal Line Resistance from Sensor Connector to Engine
Controller Connector,is Circuit Reading Open?
Yes : Repair Signal Return Line for Open
No : Replace Engine Controller
YES... Jumper Signal Line to Signal Return Line and Read Voltage,is Voltage
Reading 0?
No : Repair Open in Signal Return Line
Yes : Replace ACT Sensor