Temperature gauge senders

[dnb]

I've just boiled them up and plotted curves...




(Temperature in C on X axis and resistance in ohms on the Y axis)


Is it me or does the original Rangerover one saturate at about 90C (at atmospheric pressure)? The resistance curve looks about right, so the sensor is probably OK, but given the saturation point, I wouldn't want to use it to watch the coolant temperature!

It's a shame the TVR sender is in such a silly place for flow!

Now to work out the calibration I need for the temp gauge...

[dnb]

None! It seems the gauge works with the TVR sender with only a 2deg error (approx) for the majority of the range. I'm impressed.

Just need to put it all back together now...

[GreenV8S]

Interesting that the calibration curve you labelled TVR Sender looks identical to the coolant temp sender used by the ECU. I've never measured the sender for the gauge but your measurements seem to show that (on your car, at least) the two senders have identical characteristics?

[dnb]

Seems that way... (I've definitely got the right sender! The ECU one has 2 pins.) I dug out my tests on the ECU temp sender and they are both the same on my car.

I just wish there was a way to get the sender properly in the coolant flow so it reads a sensible temperature. The Rover one was in a better place. Oh well, maybe I'll modify that bit as well as everything else...

[GreenV8S]

dnb said:

I just wish there was a way to get the sender properly in the coolant flow so it reads a sensible temperature.

The are several points in the inlet manifold that can be tapped for a temp sender, if any of yours are tapped with the right thread you could use them instead? Alternatively, when I redid the plumbing on mine I moved the ECU sender to the top hose, I guess you could do similar for the gauge sender as long as you give it an earth.