Fooling the MTronic computer via the temperature sensing thermistor.

[Del_]

There was a posting on here by a fellow who said they had experimented with fooling a computer on a bike by placing a small resistor in series with the temperature sensing thermistor.

The computer read the temperature as being slightly cooler than the thermistor was telling it that it was and therefore ran a slightly richer fuel/air ratio.

I have both a 241C and a 362C Stihl saws.

This subject interest me very much and it may be a way to gain power head longevity while maintaining excellent running performance.

Looking for input.

 

[echomeister]

disconnect one wire from the thermistor. Put the saw in a cold environment for several hours. Cold being the temperature you want to spoof the saw into thinking the current temp.

Measure the resistance at the cold temp.

Let the saw come to 70 deg F and measure the resistance.

Add a resistor in series that is the difference in these two resistance measurements and you have spoofed the saw temp by that amount.

 

[Del_]

disconnect one wire from the thermistor. Put the saw in a cold environment for several hours. Cold being the temperature you want to spoof the saw into thinking the current temp.

Measure the resistance at the cold temp.

Let the saw come to 70 deg F and measure the resistance.

Add a resistor in series that is the difference in these two resistance measurements and you have spoofed the saw temp by that amount.

So is the thermistor only measuring air temperature?

Some experimenting and monitoring spark plug appearance would be interesting.

I know basic electronics but don't know much about chainsaw motors.

I'm assuming that the 241C that I love so much, and runs so well may benefit from an every so slight modification.

Is there more than one thermistor monitoring temperatures?

A rheostat may come in handy but would be bulky.

Thanks for your input.