HPTuners question

Quote:

Originally Posted by KYWes

I've written a math function in Math Parameters Manager to transform the voltage input from my fuel pressure sensor to PSI read out.

I've added the channel, I go to Transform then I went to User Defined and my function is not there. How do I apply it as my Transform function.

I've also created a gauge and a chart. When I monitor the channel, gauge, and chart all show the same info...the actual voltage being input to the MPVI2 Pro-Link so it isn't being transformed.

I'm not seeing how to use the formula I've created in the Transform function.

I've gotten answers to my questions working with Tech Support at HPTuner.

First my assumption was wrong regarding using a Math Parameter on a Transform. A formula created in Math Parameters is not for use on a Channel Transform. Formulas created with the Math Parameter Manager are for use with the Graph, Chart, and Gauge functions only.

Secondly, my formula was good but I did not have my parentheses or brackets placed correctly. Once I straightened these out my formula worked like it was supposed to.

My situation:
I have a Glow Shift Fuel Pressure sensor/gauge system. The Glow Shift provides voltages from 0 to approximately 3 volts. In contrast AEM and others use a 0-5v scale. Using data provided by Glow Shift I created a formula to convert the voltage supplied by the sender to a number representing the fuel system PSI. The formula is ([30012.10]-O)/M

[30012.10] is a code in HPTuners that represents the volts provided on the Blue Channel of the MPVI2 Pro Link connector.
O represents the offset
M represents the multiplier
(I can also tweak the variables of the formula to ensure what is logged in HPTuner matches what the gauge reads.)

Using a data chart from Glow Shift for their sender, I calculated the Offset at .5v and the multiplier as .02758. Thus O and M are constants in the formula. The result is a number corresponding to the PSI of the Fuel Pressure on my 1995 Z28 Camaro.

Now that I've got the process working, I can record the fuel pressure of my car under driving conditions. Under normal driving this is pretty useless data though it will show if the fuel pressure is out of spec.

My main purpose for this effort is to view and log the fuel pressure under WOT acceleration on high rpm conditions. This should help me know if my fuel pump and fuel system is providing the necessary fuel pressure for maximum power.

Note that HPTuner has formulas for other manufacturers, namely AEM, so this was only necessary because I had a Glow Shift Fuel Pressure gauge. The Glow Shift gauge kit is good quality and less expensive.