Using existing temp gauge with megasquirt sensor

[shynsy]

Hi all,
Please excuse this question if it has been answered 100 times before, but this is my first post!
i have just got a megasquirt which I plan to use for a '73 lotus twincam..
My question is, if I use the original megasquirt water temperature sensor, is there any way of taking a signal from this sensor to use for my dashboard water temp gauge (smiths). The OE sensor on the lotus twincam is a ford model from the '70s..
thanks for any help
Tim

[Matt Cramer]

Probably not, but there's a chance you could do this. See this entry on sharing the sensors with a stock ECU:

http://www.megamanual.com/v22manual/sharesen.htm

The same principle applies to sharing sensors with a gauge. Some gauges have such a low "bias resistor" value that this is not practical, while others have enough resistance to make this possible.

[shynsy]

Thanks matt,
Guess I better measure the resistance of the senders!
Tim

[shynsy]

Was otherwise wondering whether there was some kind of pulse width hardware that would convert the resistance of the new sensor into pulses that would simulate the current through the old sensor, allowing the old gauge to work properly
tim

[Matt Cramer]

Was otherwise wondering whether there was some kind of pulse width hardware that would convert the resistance of the new sensor into pulses that would simulate the current through the old sensor, allowing the old gauge to work properly
tim

It's possible this may be done with the GPIO board, but right now there is not any device to do this. There's some work at using the CANbus to drive stepper gauges, but these are not quite the same thing.

[Hey_Allen]

Is there any chance you could use the stock temp sender and map it's response curve into MS?

As the suggestion a couple of posts up mentioned, if the bias resistance of the gauge is high enough, the MS and the gauge can share the sensor output, as they won't affect it's value enough to change what the other device is seeing.