Defender 90 2.0 MPI Radiator Fan issue

marjon · Sep 30, 2021

Sounds like its working correctly.
If I remember the circuit it is sensor to ecu then ecu to relay to fans. so if you are switching the sensor the ecu is doing its bit.

If there was no water at the sensors then sounds like you have air in the system which wont help the sensor readings or your overheating issue.

J

DiscoMPI · Oct 29, 2021

Hi guys
I checked the temperature sensor resistance from cold to hot but it works in the opposite way if the target is to open the circuit. In fact when the water gets warm the resistance goes down. And also the old sensor does the same... So I have more doubts now...

marjon · Oct 29, 2021

If you show how (pics) and which readings I could probably check ours over the weekend.

OrI could just check how I would do it and it could be diff

if you know what I mean.

J

DiscoMPI · Nov 2, 2021

Yes please let's try to describe your process... I'll try to do it. Thanks

marjon · Nov 2, 2021

Have a little read here Help with a 1997 Defender 2 litre petrol | LandyZone - Land Rover Forum

I can measure the resistance across the 2 temp senders Hot & Cold, is that what you did?

Will check tomorrow for you

J

DiscoMPI · Nov 3, 2021

Yes exactly! I put the sensors in a pot and warm the water till boiling

marjon · Nov 3, 2021

@DiscoMPI
Here some pics from today.
First 2 are cold engine not been running.
Next 3 are with the cabin gauge about a 10 'O' clock.
Next 3 are with it as hot as it would get on the drive cabin gauge about 11 'O' clock.

The thermostat had opened in the last set, Normal driving for us the cabin gauge is 12 'O' clock.
If I disconnect the green plug with engine on it will turn on the fans and raise idle slightly.
Although its a green plug the sender is blue, I have a new (looks unused) spare that was in the battery box that will act the same way with just body heat (holding in my fingers) the res will drop.
The new 1 has a number on the packet AS2078 but other than it being a blue cap I dont know if its the right 1.

Hope that helps

.

J

mystery · Nov 3, 2021

if i recall the The sensor comprises a temperature dependant resistive metal strip. The resistance of the strip varies
considerably with coolant temperature, i.e. from 28K ohms at - 30°C to 90 ohms at 130°C. At 85°C the resistance is 300 ohms. The ECT sensor signal is vital
to engine running, as the correct fuelling is dependant upon engine temperature i.e. richer mixture at low temperatures.this is taken from the RR P38 INFO

DiscoMPI · Nov 4, 2021

marjon said:
@DiscoMPI
Here some pics from today.
First 2 are cold engine not been running.
Next 3 are with the cabin gauge about a 10 'O' clock.
Next 3 are with it as hot as it would get on the drive cabin gauge about 11 'O' clock.

The thermostat had opened in the last set, Normal driving for us the cabin gauge is 12 'O' clock.
If I disconnect the green plug with engine on it will turn on the fans and raise idle slightly.
Although its a green plug the sender is blue, I have a new (looks unused) spare that was in the battery box that will act the same way with just body heat (holding in my fingers) the res will drop.
The new 1 has a number on the packet AS2078 but other than it being a blue cap I dont know if its the right 1.

Hope that helps.

J

Thanks a lot for this check!! I'll do the same but I see that also your sensors decrease the resistance with the temperature. Hopefully my sensors have not correct values or I have to change also the fuel temperature sensor.
Again, thanks a lot I'll make you boring with some news...

Defender 90 2.0 MPI Radiator Fan issue

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