Water temp guage with Aftermarket ECU's
Turbo Mini Forums

Good Day All.

I know that the Water Temp Guage on the Rover Mems mini's are controled by the ECU it's self.

What is the best way of getting the Water Temp Guage working.

Thanks for your time.

It's always better to have independent gauges for ECU and for dashboard. Reliability and cross-checking.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

alpa I totaly understand that, but I don't like extra guages slaped here there and eveywhere. Witch is why I asking can I use the stock temp guage.

From reading the Rover MEMS manual, it looks that the water temp guage works from a earthed SquareWave singal.

Quote:
The engine coolant temperature gauge on the instrument panel is connected to earth through the ECM.
MEMS actuates the gauge and warning lamp by rapidly pulsing the ECM connection to earth.
This produces a square waveform of variable frequency and duty cycle.
The frequency increases as the engine temperature increases and the hotter the engine, the lower will the average voltage become.
In addition, the duty cycle will also change.

Edited by Mad Professor on 1st Jun, 2008.

Wow, if something simple exists there always be an engineer to make it complicated LOL.

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

Hi,
I don't know of an aftermarket ECU that can do this.
So your choices are...
LCD on the dash giving you ECU info, useful for WBO2 monitoring too.
Or fit a sender unit in the lower part of the thermostat housing. I'm going for this one and getting a boss from Pace tigged on
Cheers,
Gavin :)

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I would fit a standard sensor in the head or, as Bat says, in the thermostat housing.

Then fit a standard temperature gauge in the gauge pod.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

As said above I want to keep the stock water temp guage, and don't want to stick pods and gauges eveywhere.

In my spare time I mess about with PicAxe Programmable Microcontrollers, I should be able to use the low end unit to read the stock water temp sensor, without giving any problems / misreadings to the ECU, and then read and convert the reading from the sensor to a usable output for use with the stock temp guage.

As I own a Rover Merto 1.4 16v GTi also using rover mems, I can use a USB Scope to read the signal from the MEMS to the temp guage.

I just need to find out the frequency and duty cycle at a few ref points, say at 50c, 75c, 100c. then I should be able to wite a small pice of software for the PicAxe Microcontroller.

If anyone can think of an easyer way please let me know.

Edited by Mad Professor on 1st Jun, 2008.

Just connect the gauge to a standard temp transmitter of ye olde carbie cars. Finding a location for it is the dificult bit.

You need to splice into the green/ blue wire.

Works as normal