Custom PID assistance for logging 4L80E pressure

[5.7stroker]

I'm using a Lowdollar 0-300 PSI pressure sensor part number 7990300 which is 0.5v - 4.5v and scales linear. How can I set this sensor up to log pressure when placing it in the 1/8NPT port of my 4L80E and using an MPV1 Pro?
Application is a 2000 4th gen F-body with a completed 4L60E to 4L80E segment swap.

I'm assuming I want to go to Tools/Math Parameters/ and then select "user math 1" but what do I put in for Parameter? Under Pressure Sensors there's AEM, PLX and GM. Do I just select AEM 500PSIg and modify it to 300 PSI somehow by changing the expression, or do I go to MPV1 A/D Input 1 (external input) and use volts as the units? If so, for period then how many ms? What needs to be entered into the "expression" field? I change units to psi in the unit field? Once the math is done, how to I log it correctly then to display pressure in PSI?

[5.7stroker]

So.....

0.5V = PSI of 0
4.5V = PSI of 300

y=mx+b

Figuring out slope

(300 - 0) / (4.5 - 0.5) --> 75 PSI per volt

Then figure out offset

At 4.5V the PSI is 300, so

300 = 75 * 4.5 + b
300 = 337.5 + b
b = -37.5

So the right formula is 75 * voltage + (-37.5)

Testing to be sure

75 * 4.5 + (-37.5) --> PSI of 300 (checks out)
75 * 0.5 + (-37.5) --> PSI of 0 (checks out)

So the formula is then:

(V / 0.01333) - 37.5

??

[5.7stroker]

Making progress...

Some questions based on screenshots I took:

1. The first image shows A/D port 1, but I had changed it to port 2 so ignore the parameter as showing up as port 1 in the image. Should the special function be "slope", "average" or "none" for this type of sensor?

2. Should the period be set to "0 ms"?

3. Is the expression as seen in the image correct? ([30002.10]/0.01333)-37.5? (image is wrong, should say 0.01333 not 0.1333

4. I noticed that the units drop down box was blank. I couldn't select PSI. I saved the file, went back and PSI was auto populated. What would cause this?

5. Decimals I'm assuming should be "0" as the output is PSI on a scale of 0-300?

6. Are the details seen on the "Group" screen showing Group 6 as Tpress correct?

7. When I go to add the channel, I selected A/D input 2, then right click on this PID and select "unit transform", but when I go to select the parameter it doesn't show any user defined parameters as an option. So I chose "PLX vacuum/Boost as the parameter" and put the units as PSI, entering the same transform equation. Is this the proper way to do it?

8. When you right click on the channel and show the units as seen in the last image, it still shows as volts. Is this correct even though I want the units to display as PSI?

Please advise if I missed anything or if any of this is incorrect.

[5.7stroker]

OK I can get the gauge to show up as a PID using input 2 and display the pressure using one of the AEM pressure sensors as the selection and using the formula above, but then it won?t show up at all in the chart. If I keep the PID as is, with units as volts and no transfer function, it?s won?t show up in the chart correctly using the transfer function. HP tuners is seeing the voltage correctly from the sending unit at 3.4v, I just can't get it converted to PSI for some reason on the chart to log it. It?s showing up as -34 PSI on the chart when it should be 218 PSI for that voltage for example.

Has anyone ever logged transmission pressure using a 0.5 - 4.5v / 0-300 PSI transducer on an MPVI1 and if so, how did you get it to display in the chart? Post up the user defined math and transfer function windows if you have them so I can see what I'm doing wrong.