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Using the MAF Flow Curve for Temperature

Old 05-16-2016, 06:48 AM
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Default Using the MAF Flow Curve for Temperature

I've already got a VDO Oil Pressure sensor (1/8" NPT) installed in my MSM and would like to connect it to the MegaSquirtPNP Pro MSM0405 I've just purchased.

The sensor is a typical thermistor so has its own voltage vs resistance curve, it's not linear and it doesn't match the GM thermistor curve so I can't use those two as the transformation.

When defining the Generic Sensor Input transformation for the VDO sensor, I could just specify Raw so that the ADC value is logged/displayed.
I realise that I can post-process these values to temperature values but I'd rather just record the temperature based on a mapped curve if possible.

Since I'm not using the MAF sensor, is there any reason I can't simply define the MAF Flow Curve based on my VDO sensor's calibration curve (ie. specify temperature instead of flow) then specify "Same as MAF" as the VDO sensor's tranformation?

The other/simple option is to replace the VDO sensor with a Standard Motor Products TX73 Coolant Temp Sensor (same 1/8" NPT thread) and specify the transformation as "GM calibration".

Also, is there an Analog Input 3 on the Rear Option Connector of the MegaSquirtPNP Pro ECU?

The Web page shows:
B Knock Sensor 2
C Analog Input 2
D Analog Input 1
F External MAP Sensor

Is it B, E or F?
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Old 05-16-2016, 10:28 AM
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I use a GM coolant temp sensor from a Saturn. They are pretty cheap. Not sure about the maf curve. Msextra would get you better answers.
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Old 05-16-2016, 06:57 PM
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Signed up and posted the question at - will add the response here too to close out the thread (I hate it when people post questions but not the solutions).
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Old 05-17-2016, 03:20 PM
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Analog Input 3 is hardwired to the internal baro sensor and not brought out in the wiring.
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