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| bradders |
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hi folks, was wondering if anyone knew the resistances of the coolant and air temp sensors with temp?? or just the part numbers??
if anyone knows the biasing resistor values inside the EEC-V too that would be swell. i measured the sensor resistances (with the ECU connected tho) then the voltage: Code: sensor resistance voltage temp coolant 7.81kohm 1.861 50 air 790ohm 2.985 24 i worked out the current then the voltage drop across the unknown resistor lalala (and double checked with the potential divider rule) to give Code: ECU: coolant biasing resistor: 42.550Kohm air biasing resistor: 876ohm is there any chance anyone could confirm these numbers (its possible the resitance values may be different since i didn't disconnect the ECU to measure them)
_________________ PH 4480 racing extractors
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| bradders |
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Hi folks
This is what i managed to come up with, not as accurate as i'd like but should be suitable for an aftermarket computer, i used the voltages specified in the technical documents section on the EEC-V (although that was for an EF, http://www.fordmods.com/documents.php?d=42). From my own measurements i determined that the internal biasing resistors in the ECU must be 43K +/-10% for coolant and 2.4K +/-10% for the air temp, thus: Code: air temp -bias 2446 ohm 0C 3.9V 1146ohm 20C 3.1V 831ohm 40C 2.2V 537ohm Code: coolant temp -bias 43503 ohm
20C 3.1V 14776ohm 20C 2.2V 9545ohm 40C 0.5V 1855ohm
_________________ PH 4480 racing extractors
Last edited by bradders on Thu Dec 31, 2009 4:23 pm, edited 1 time in total. |
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| bradders |
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it appears that no one seems particularily interested. but i've just noticed that the ECU switches its biasing resistor once the coolant temperature starts to get hot ~80C.
_________________ PH 4480 racing extractors
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| EL__Fairmont |
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10C--58.75kohms
20C--37.30kohms 30C--24.27kohms 40C--16.15kohms 60C--7.60kohms 80C--3.84kohms 100C--2.07kohms Ign on coolant temp sensor engine at 20C---3.1V engine at 40C--2.2V engine at 100C--0.5V Ign on intake air temp sensor engine at 0C--3.9V engine at 20C--3.1V engine running air temp at 40C--2.2V
_________________ 97 EL Fairmont 4l OHC .Silver. |
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| bradders |
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Cool thats really handy! thanks for that! how'd you get all that info, did you work it out empirically or did you have a handbook?
The voltages are handy. However, i noticed that the voltage jumped to like 4.5 once the engine started to get hot like ~80-90C. I had assumed that the EEC-V had switched biasing resistor to match the lower resistance range at the hotter temperatures to allow for higher resolution (due to the logarithmic nature of the NTC thermistor) but it would make sense that if there was an open circuit the signal would match the reference voltage source in the ECU, i had assumed it would have been 12V, but since most microcontrollers are 5V perhaps the reading of 4.5V does indicate an open connection to the sensor for some reason.
_________________ PH 4480 racing extractors
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| 4LEDboy |
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Temp sensor, Tridon part No TCS134
However the air sensor is combined with the MAP sensor (T-MAP)
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