MegaSquirt Question?, Need help with setting the expanded temp limits Options

[falconfp2001]

I've installed and got the engine to run and idle pretty well but I still can not find how to set the expanded temps ranges for Tuner Studio. I have them set for Megatune but Tuner studio instructions are not working.

Here is the section in the manual that discusses the Expanded Temps

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To use a MegaSquirt® controller with an air cooled engine, you will have to decide where the best place is for the coolant sensor: in the oil, or on the cylinder head (CHT). There are various arguments for and against using either CHT or oil temperature as the 'coolant' temperature input on air cooled motors. A lot depends on whether the motor is substantially oil cooled or not. Since the CTS input is used for warmup enrichment, you want something that responds fairly rapidly, so this is highly engine-dependent.

For high temperature applications (i.e. air cooled engines with a CHT), in MS-II you can set the #unset EXPANDED_CLT_TEMP by changing:

#unset EXPANDED_CLT_TEMP

to

# set EXPANDED_CLT_TEMP:

Then the upper temperature limit should be 600 degrees F. This is from the INI notes:

; FAHRENHEIT (Expanded/Normal):
; Low Limit: -40F/-40F
; High limit: 600F/300F
; Low danger: 150F/50F
; Low warning: 200F/150F
; High warning: 325F/200F
; High danger: 350F/220F

However, you have to calibrate the thermistor table(s) appropriately.

However, note that the tuning software limits the temperature range. The thinking is that if you are at an extreme it is probably a bad or missing sensor, so it goes to a default value. This isn't a big deal in TunerStudio though, you can change these limits in the ms2ReferenceTables.ini file. You can adjust these limits if EXPANDED_CLT_TEMP is set. Currently only the CLT sensor respects EXPANDED_CLT_TEMP, the IAT does not.

IAT min = -40, max=350 if outside that range it goes to 70 CLT min = -40, max=350 if outside that range it goes to 180 CLT with EXTENDED_CLT_TEMP min = -40, max=400 if outside that range it goes to 350 default

Here is the section of the ms2ReferenceTables.ini file that controls that:

; tableLimits (optional) = intentifier, min, max, defaultVal
; will set the default value if value is outside the min and max limits.
tableLimits = 001, -40, 350, 70
#if EXPANDED_CLT_TEMP
tableLimits = 000, -40, 400, 350
#else
tableLimits = 000, -40, 350, 180
#endif"

So the user can just edit the one line in ms2ReferenceTables.ini using notepad.exe or something similar to change it from:

tableLimits = 000, -40, 400, 350

to something like:

tableLimits = 000, -40, 600, 350

or similar, and it should work once the user re-burns the table.

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In Megatune, you can use the configurator to set the

#unset EXPANDED_CLT_TEMP

to

# set EXPANDED_CLT_TEMP:

But in TunerStudio you have to edit the ini file and I've done both which only shows the expanded temps in Megatune and not in TunerStudio.

Need Help you guys?

[underthetire]

And once you get it to work, once the temp gets above 345 or so, megasquirt will go in to default of 180. It's the sensor, its just not a linear enough sender.

[rwilner]

And once you get it to work, once the temp gets above 345 or so, megasquirt will go in to default of 180. It's the sensor, its just not a linear enough sender.

Not sure I understand your logic here. Regardless, I and ( I think ) frank are running automotive grade thermistors in the cht body and not the stock cht. The device is intended exactly for this purpose so linearity should not be an issue.

Frank, I have the thermistor characterized and calibrated. I get proper chts reported in my datalogs -- they match my cyl head temp sensor under the #3 plus pretty closely -- but i believe we still need to set that parameter somehow for the fuel injection to run as intended.