MAP sensor calibration

[Eric Elliott]

>Instead of having to use charts to calibrate a MAP sensor -- charts that
>have been derived from some "standard, ideal condition MAP sensor" -- why
>not create your own chart for your own MAP sensor?  That way it will be
>guaranteed to be accurate with your sensor ...  [I derive this from the
>pressure transducers that we use at work to measure water level in a vat
>of paper stock -- inches of water level is much more sensitive than
>inches of Hg!]  ...

I think that comparison of data taken from “standard, ideal condition MAP 
sensor”s  purchased in a Georgia salvage yard, will show the sensors are quite 
linear and consistent, even after traveling all the way to the salva ge yard. 
Also, the ECU doesn’t get data from calibration of individual sensors, it just 
lives with the sensors as installed.

>Procedure:  Create a manometer from a couple of clear pieces of acrylic 
tubing.
>And 2 clear acrylic 90's for the tubing...
>For example, to measure to 30" of Hg, one side needs to be about 17" and
>the other side needs to be about 34".  Diameter of the tube doesn't matter
>except for cost (remember you must fill the tube with Hg!) ...

Use water NOT Hg, for 13.54:1 better resolution, same accuracy and zero 
toxicity. A Hiese digital manometer was used to calibrate the five sensors. 
Can you visually resolve 0.001 inch Hg? The Heise digital pressure gage u
sed to calibrate the sensors may have been much more accurate than the 
technician that used it. As I wrote with the sensor data, the units of measure 
are suspect.

Eric Elliott