Scoobyturbobug

How can you test a water temp sender? does anyone know the resistance of a good sender or does anyone have a good sender lying around that they can test for me? so I can can test mine as I think it's knackered

Scoobyturbobug

surely someone has a good sensor lying around you could test for me and everyone else who seems to be having this problem at the moment. Pleeeeease unless of course there is no way of testing them

[Davey]

Ahh bugger! I tested my new sensor to compare it against the duff one, I cant bloody remember what it was though, I just dug out the meter and checked the memory, I didnt have the data logging on

andy97

iTrader: (1)

Most temp sensors are NTC (negative temperature coefficient), this means that with an increase in temp the resistance of the sensor lowers. Take it out and measure the resistance at room temp. Place in a cup of boiling water and watch the multi meter resistance, it should drop rapidly.

Obviously there will be an exception to the norm and the temp sensor could be a PTC.

Andy

Scoobyturbobug

thanks Andy i'll give it a go

Scoobyturbobug

tested it last night and when its cold it reads around 3.169k ohms and when placed in boiling water it goes down to around 380 ohms.
Quite a difference between cold and hot but can anyone confirm if these reading are good or not as it may be reading too high when cold and causing my cold starting problems?

andy97

iTrader: (1)

That indicates that its a ntc and I believe the resistance swing is reasonable. Sometimes there is a code which gives an indication to its resistance printed/stamped on the device.

To test if it should be higher add another resistor in series with the sensor(2.7k ohms 1/2 watt) or just unplug it, this will give open circuit condition, the ecu might need a pull down resistance for it to function properly- dont know on this latter point,

I cant test mine sensor, cause the car is a hundred miles away.

Ive just noticed that you are near Api, I would take it in there if it continues, at least they will have items to swap for testing.
,
Andy

Scoobyturbobug

Thanks again Andy might give the resistor a go if no one else is able to test a good sensor for me