Gold FFM Gjk Posted October 12, 2022 Gold FFM Report Share Posted October 12, 2022 Does anyone know what the resistance should be of the MAT sensor when cold? Car is a 1991 turbo se. Quote It’s only metal, it cannot win! Link to comment Share on other sites More sharing options...
Gold FFM Escape Posted October 13, 2022 Gold FFM Report Share Posted October 13, 2022 The MAT sensor is NTC, which means a low temperature will give a high reading and vice versa. The manual says 100 kOhm at -40°C and 185 Ohm at 100°C. Ambient will be a few kOhm. I can check tonight if you want (and I don't forget...). Filip Quote I have made many mistakes in my life. Buying a multiple Lotus is not one of them. Link to comment Share on other sites More sharing options...
fjmuurling Posted October 13, 2022 Report Share Posted October 13, 2022 The resistance values for the various MAT sensor temperatures is also given in the EMH manual. Quote Esprit Freak Link to comment Share on other sites More sharing options...
Gold FFM Gjk Posted October 13, 2022 Author Gold FFM Report Share Posted October 13, 2022 I have just hooked my sensor up to a multimeter and it’s reading 3.54 kOhm. The indicated ambient temperature in the room is 19 degrees (household central heating thermostat). does that sound like a reasonable resistance for the temperature? I would be interested to see what @Escape gets, only if it’s not too much hassle. Quote It’s only metal, it cannot win! Link to comment Share on other sites More sharing options...
Solution fjmuurling Posted October 14, 2022 Solution Report Share Posted October 14, 2022 According the EMH Manual the resistance of the MAT sensor at 20 degC is around 3400 Ohm. So your measured value sounds right. Be aware that the sensor resistance is not lineair with the temperature. Quote Esprit Freak Link to comment Share on other sites More sharing options...
Gold FFM Gjk Posted October 14, 2022 Author Gold FFM Report Share Posted October 14, 2022 Thanks @fjmuurling. I did not realise the relationship between resistance and temperature was not linear. Quote It’s only metal, it cannot win! Link to comment Share on other sites More sharing options...
Gold FFM Escape Posted October 14, 2022 Gold FFM Report Share Posted October 14, 2022 I got 3.955 kOhm at 16.6°C, very much in line with what you found. At lower temperatures the resistance rises rapidly, as with most sensors. I had a quick look through the EMH but didn't find a detailed temperature/resistance graph. Quote I have made many mistakes in my life. Buying a multiple Lotus is not one of them. Link to comment Share on other sites More sharing options...
Gold FFM Gjk Posted October 14, 2022 Author Gold FFM Report Share Posted October 14, 2022 Thanks @Escape, most kind of you to cram yourself into the engine bay on your SE! Much appreciated. Quote It’s only metal, it cannot win! Link to comment Share on other sites More sharing options...
Gold FFM Escape Posted October 14, 2022 Gold FFM Report Share Posted October 14, 2022 Anything to help out a fellow Esprit owner. 😉 And it really wasn't too hard to reach the sensor... 1 Quote I have made many mistakes in my life. Buying a multiple Lotus is not one of them. Link to comment Share on other sites More sharing options...
Gold FFM Gjk Posted October 14, 2022 Author Gold FFM Report Share Posted October 14, 2022 Ah-ha, I see! Much better access! I’m now suffering from workshop envy…. 😢 Quote It’s only metal, it cannot win! Link to comment Share on other sites More sharing options...
fjmuurling Posted October 14, 2022 Report Share Posted October 14, 2022 3 hours ago, Escape said: I had a quick look through the EMH but didn't find a detailed temperature/resistance graph. EMH4 page 45 1 Quote Esprit Freak Link to comment Share on other sites More sharing options...
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