Adding an NTC oil temperature sensor to MS3pro

[Baxsie]

I wanted to add an oil temperature sensor.

I have an air-cooled VW, my CLT is reading head temp using a GM sensor, and the AIT is also using a GM sensor, both of which work fine. I have a separate Baro sensor connected to analog input 1.

So I hooked my oil temp sensor up to analog in 2, using a 1K pull-up.

In the Advanced Engine/Generic Sensor Inputs, I made Sensor 01 look at Analog In 2 and named it Oil Temp. If I set it to RAW and assign it to a gauge, the ADC reading corresponds nicely to what I would expect from my spreadsheet, the cold engine temperature and reading the sensor with my ohmmeter. So I am pretty sure that the hardware is good.

I can easily generate a table with 1024 lines, each containing a number that corresponds to the sensor temperature in degrees F for that ADC reading.

How can I tell the system to use my table? I understand that I need to create an INC file, but when I copy example INC files into my C:\Users\Brent\Documents\TunerStudioProjects\(project) or C:\Users\Brent\Documents\TunerStudioProjects\(project)\inc or C:\Users\Brent\Documents\TunerStudioProjects\(project)\projectCfg directories, the system does not seem to know about them.

What I really want is for my thermistor table to show up in the "Transformation" pull-down of the Generic Sensor Inputs dialog, right?

Do I need to edit the very scary mainController.ini file?

Can someone walk me through the step-by-step of how to add an NTC oil temperature sensor to the MS3Pro software?

Or if you can point me to a tutorial or example somewhere?

Thanks in advance for any help you can offer.

[grom_e30]

when i added my oil temp sensor i used the same sensor as my water temp and use the same sized bias (pull up) resistor as what is used inside the ecu for its sensors that way i could use the same calibration data without having to edit any ini files

[Baxsie]

. . . used the same sensor as my water temp . . .

Due to size constraints, I used a smaller sensor. The GM sensor would have been very bulky to fit in. The one I have is 1/8 NPT.

In my head, I just thought it would be fairly simple to add a new "oil temperature" sensor to the MegaSquirt.

Under "Tools", "Calibrate Thermistor Tables" I see the pull down for "custom inc file", but it can only be applied to "Coolant Temperature Sensor" or "Air Temperature Sensor". Is that where it needs to go? How would I add "Oil Temperature Sensor"? How would I link that back to the generic inputs?

[grom_e30]

can you find a sensor that uses the gm calibration but has the 1/8th thread i seem to remember someone mentioning that they do exist.

as far as im aware you cannot add another inc file.. and if you mod the ini i believe the data logged would be the raw adc value where as if u do it the way i mentioned it will show the actual temp in data logs.

[billr]

Standard Motor Products #TX73 is a GM temp sensor with 1/8" NPT; was used on '91-'01 S-series Saturns.

[grom_e30]

Standard Motor Products #TX73 is a GM temp sensor with 1/8" NPT; was used on '91-'01 S-series Saturns.

boom

for this to work you will need to use the same pull up resistor the ms3 pro uses for its other sensors i think its a 2.49k.

[Baxsie]

Hey guys, thanks for the help. If I had only known that it was this big of a deal to add a new sensor, I would have got a GM compatible one for sure,

Well I guess I could drain the oil again, throw away the sensor I just bought, cut off and throw out the cable end, order a new sensor, order a new connector, cut away the 1K pull-up, throw that out, order a 2.49K 1% from DigiKey then solder/crimp/heat shrink/install it all back together and put new oil in.

There I was thinking that it would be easier to type a bit to fix it

Heh, maybe I'll just log it as raw ADC, print out a little chart and tape to to the dash

"Oh man, the oil temp is up to 219, if it gets up to 199 we are going to have to pull over and let it cool down."

[billr]

I think there is a way to do this with just TS settings, I don't know how myself; I was just offering the TX73 info. Wait for somebody else to join in.

[grom_e30]

http://www.msextra.com/doc/pdf/Megasqui ... ce-1.3.pdf

pages 224 & 225 covers the generic sensors.

[Baxsie]

. . . Megasquirt3_TunerStudio_MS_Lite_Reference-1.3.pdf: pages 224 & 225 covers the generic sensors.

Yes. But the only choices are the canned choices that came pre-programmed, with no option for a custom thermistor curve.

It appears that there is a limitation of only two thermistor tables. You can modify either one of them in the "Calibrate Thermistor Tables" dialog, but at the end of the day it looks like there is only one table for "Coolant Temperature Sensor" and one table for "Air Temperature Sensor".

Since both my CLT (head) and IAT/MAT are "GM" sensors, I thought of making one table "GM" and a second custom table for my custom thermistor. But that does not work, since it looks like the CLT is hard coded to use only the "Coolant Temperature Sensor" and the "IAT/MAT" is hardcoded to use only the "Air Temperature Sensor". So even though I only have two thermistor curves active in the system (CLT and IAT/MAT are all "GM", plus my custom curve for the oil temperature), it still cannot work since the CLT and IAT are coded to use one each of the two (identical, in my case) curves.

I hope that I am wrong, and that there is a way to add an additional thermistor table. It seems like a pretty serious limitation, and in general it the MS team does not code themselves into a corner like that.

I am starting to see why you recommended just junking my new/expensive/accurate sensor and getting a "GM" curve one

[grom_e30]

the options are to same as clt, same as mat or gm calibration.... i wonder where it takes the gm calibration from?? could you in theory edit that gm calibration to match your sensor, then create a custom inc using the gm data for you mat and clt sensors.

[racingmini_mtl]

If this is for logging and display purposes only, you can create a custom.ini file and use the 'table' function which will use you inc file. Since this is a TunerStudio function, ask on the TunerStudio forum how to create this if you need help.

Jean

[Baxsie]

I'll look into what it takes to do the custom. Inc.

I did have in mind to use this oil temperature reading, the oil pressure, and the CLT (actually my CHT) in combination to activate the CEL (check engine light). Maybe that could be done with the raw ADC information.

We also plan to run Shadow Dash on a tablet. I wonder if Shadow Dash would have the same problem showing customer sensors in real life units.

[vw_chuck]

This is tragic. I thought MS3X was supposed to be the most flexible ECU out there. They don't even have basic transfer function mapping for different sensors. What is the deal???

[Reverant]

Agreed, we should be able to add at least two more tables for custom transfer functions.

[jsmcortina]

I'd hardly call it a tragedy. However, I already plan to remove the old-style MAF calibration and make it a customisable calibration for sensors.

James

[billr]

Yeah, that GM sensor I referenced before can be had (new) for about $10; hardly a "tragedy" to have to use it and not fuss with cal curves.

[vw_chuck]

This is for a generic sensor input. It is doubtful you would be using a GM coolant temp or air temp sensor again since you are already measuring these temps. What if you want to measure something higher temp than 300f like EGT or something? What if you need something smaller to fit in a tight region?
That GM sensor is very limited.

[grom_e30]

a lot of bosch sensors use he same calibration as other bosch sensors, and are smaller m12 or m10 thread size.

for egt you usually use a thermocouple these require some form of a signal amp so usually output a 0-5v linier signal

[billr]

Aren't we wandering "out in the weeds" here? This thread started with asking about an "NTC sensor", which I think means "negative-temperature-coefficient" and applies commonly to thermistors; none of which are going to hold up in high temperatures. Further, the OP was concerned only with MAT, CLT, and oil temp; all well in the range of standard sensors. For higher temps, or other inputs needing custom cal curves, there are several ways MS can handle those.