Electronic scales of temp senders
Turbo Mini Forums

Now this question isnt turbo mini related but im hoping someone will be able to help me out with temperature sensors.
Im putting a toyota starlet engine in my mini and am running an adaptronic ecu, an etb instruments digidash and a davies craig electric water auxiliary water pump.
Could i just split the signal from the original starlet temp sender into the pump controller, ecu and digidash? Or do they usually operate on different scales ie not 0-5V like electronics?
Or is there anyway to check the voltage outputs of the temp sender? Then rig up a system to match.
Cheers,
Joe

In boost we trust

So i did a bit more testing of the 2 types of sensors i have and got:
Sensor 1:
Room temp 68.6 Kohms
Boiling 65.3 Kohms

Sensor 2:
Room temp 355 ohms
Boiling 26 ohms
Does anyone know if theyd be interchangeable?

In boost we trust

well, if both are working properly, not really

its all about resistance vs temp, can you recalibrate the ecu or etb?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

Why not stick with the reliable mechanical water pump ?

And as above. As long as your ecu and dash can be calibrated for the different sensors, then anything can be used really.

No idea what the DC wants in terms of inputs though.
I wouldnt have one near my car though. I bought one a few years ago for an RV8, I ended up giving it away.
Wouldnt have the nerve to ask for money for it !!

Some people seem to get them to work, I thought it was total crap.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Without knowing exact deatils of the sensors you have, what I'm about to say is a bit of a generalisation.....

Temperature senders, especially the ones for ECUs, are usually NTC (negative temperature coefficient) so should be high resistance when cold and low resistance when hot.

They usually have quite a large range to make them accurate, ie the one is use is 9kohms at 0C and less than 200ohms at 100C.

This is because they are set up as a voltage divider by the ECU, fed with 5V through a medium value resisitor and the divided voltage measured so they need to be a long way above the internal resisitor value when cold and a long way below when hot to give enough of a voltage swing for the ECU to interpret.

It is also because of the way they are used by the ECU, they cannot be piggybacked to any other device unless it has an extremely high input impedance so as not to drag the divided voltage down and tell the EUC the wrong figure.

There are some devices that have an extremely high input impedance to allow this, but they still need to know the calibration table of the sensor (which will actually be the derived voltage as seen by the ECU) but the safest way is to use seperate sensors for each device IMO.

Sensor 1 looks to be dead, sensor 2 doesn't seem to have the range an ECU would require but temperature/resistance tables are available for all the common types in service manuals and elsewhere on the internet if you search hard enough and actually know the make/part number of the one(s) you have.

Schrödinger's cat - so which one am I ???

Thanks Rod, thats pretty much the answer i was looking for. Except a hell of a lot more in depth than i know. The sensors didnt come with part numbers or anything, so i guess ill be getting some decent ones. Sensor 1 was out from the electric water pump and sensor 2 from the digidash.

And ive got an electric water pump to get rid of the heat soak. And to fit a starlet engine in a mini ive moved the alternator to the front of the engine so theres no tensioner on the water pump belt. Just as a backup.

In boost we trust

Cant the ecu put an output to the pump controller ?

And wont the dash also interface with the ecu, to offer any information it has ?

Would negate the need for multiple anything.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

In boost we trust

The crappy DC pumps are australian.

And it shouldnt be hard for you to figure out what the controller needs in terms of an input. Just read the instructions ?

Some dashes will interface with ecu's. Does it have a CAN or Serial type connection ? Or is it a fairly basic thing that relies on external sensors ?

Just email the manufacturer ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will