Logging Pressure in HP tuners?

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Sep 29, 2022 | 06:44 AM

5.7stroker

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From: OH

Logging Pressure in HP tuners?

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.

It's a standard Delphi GT150 3 wire harness coming off the sensor so I'm assuming:

I'm assuming I want to go to Tools/Math Parameters/ and then select "user math 1" ?

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 converted formula so that it's suitable to enter into HP tuners I'm assuming is:

(V / 0.01333) - 37.5

My questions based on the images below are as follows:

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 "slope", "average" or "none"?

2. Should the period be "0 ms"?

3. Is the expression as seen in the image correct? ([30002.10]/0.01333)-37.5? (image is wrong, should say .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, so whole numbers are fine.

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 all correct? What am I missing here?

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 we want the units to display as PSI?

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

Last edited by 5.7stroker; Oct 1, 2022 at 01:24 PM.

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