owenduffy

So, putting this information to good use... The question here is whether in a particular vehicle, the dashboard gauge and ECT sensor are compatible. 1. 'cold' resistance of the ECT with wire removed is 2730 ohms at around 20C. This hints the ECT sensor is unlikely to be a AME1425 but one of the others mentioned (which are fairly similar). 2. Connecting to parallel resistors for total R=155 ohms yields the following: 3. Connecting to parallel resistors for total R=27.5 ohms yields the following: d 4. Calculating the expected temperature of the AMR1425 at 27.5 ohms from the constants above, we get: ... which was bang in the middle of the red zone. This gauge appears to be compatible with the AMR1425 ECT sensor, not the one fitted to the engine. This seems to be the result of an unprofessional / half baked conversion of a petrol vehicle to a diesel engine. Owen

I might mention that if you were trying to fabricate a sensor (eg in a stud to suit a foreign engine), R25=2k2 B=3950 thermistors are not too hard to obtain and might be a good enough substitute for AMR3321, ETC8496, ERR2081. Owen

Fixed images pasted, ignore last. Thanks TSD for measuring and publishing the NTCs above, I dips me lid to ya! I calculated two point R25/B models for each using Two point thermistor calibration . They provide a simple comparison basis. Owen