MSefi.com read only forum (Jan.15,2018)

Hello, sorry if this has been answered many times already, but I can only find info on changing a coolant sensor to an oil temperature sensor. Not adding a sensor.

I am hoping to an a thermocouple to the oil cooler line in my '86 race prepped MR2 and I had a few questions about how I might get Megasquirt to display and datalog this information.

I am using V3.57

Questions
1. Is there a channel on the board sensitive to voltage differences on the order of 0.2 mV? A typical K type thermocouple varies about 1 mV for every 40 degrees F change. Providing about 4.3 mV at 220 degrees.
2. Is it possible to calibrate this new channel (if there is one) to display temp instead of millivolts?
3. Is it possible to add this channel to the values being data logged?
4. What Pin would I use as the sensor channel?
5. Would I be better off using a coolant temp sensor instead of a thermocouple?
6. If so, what pin would I use to add a second coolant (oil in fact) temp sensor?

Thanks

ocousins wrote:Hello, sorry if this has been answered many times already, but I can only find info on changing a coolant sensor to an oil temperature sensor. Not adding a sensor.

I am hoping to an a thermocouple to the oil cooler line in my '86 race prepped MR2 and I had a few questions about how I might get Megasquirt to display and datalog this information.

I am using V3.57

Questions
1. Is there a channel on the board sensitive to voltage differences on the order of 0.2 mV? A typical K type thermocouple varies about 1 mV for every 40 degrees F change. Providing about 4.3 mV at 220 degrees.

Not with the standard parts. You could, however, use a thermocouple amplifier chip like a AD595CQ. This can then be fed to JS4 or JS5.

2. Is it possible to calibrate this new channel (if there is one) to display temp instead of millivolts?

Yes, it requires some tricks with the INI file.

3. Is it possible to add this channel to the values being data logged?

Yes.

5. Would I be better off using a coolant temp sensor instead of a thermocouple?

I would; it's a lot cheaper normally.

6. If so, what pin would I use to add a second coolant (oil in fact) temp sensor?

Thanks

JS4 or JS5, just like the thermocouples. You'd build a duplicate of the CLT circuit.

Thanks very much. Where would I find documentation on how to add this circuit? I must admit that since I bought a preassembled board I am not very savy on adding things. Is it as simple as wiring the sensor into one of the main connector pins? Or do I need to purchase some components?

Again thanks, I hope there is some documentation/instructions so that I don't have to bother people with these questions.

anyone?

This page shows the circuit you need to duplicate.