I just wanted to share my experiences of success in getting my DEFI guage to allow me to log fuel pressure. It was very easy as the guage has a 0-3v linear output on the white wire and it showed right up in the Datalogit. AllI did was play with the polynomial to get the right equasion and that's it. Took me all of 30 min including running the wire through the firewall.

 

Congrats
although I am jealous that someone has a loggable guage I don't have yet

 

I won't tell anyone

Maybe you can answer a question for me though. I made a table of voltage vs pressure off a test meter and when I looked at the #'s in FC Edit they read .2v lower, so I had to re-do my table. Why is that?

 

Sounds like the same problem that the happened to the Techedge units. You may remember that the TE 5301 display read .1 to .2 AFR off the datalogit reports. The datalogit does not have infinite impedence which essentially draws a small amount of voltage from the user input that may be happening in your case also.

One other possibility is depending on the accuracy of your dvom, either the datalogit is reading the voltage .2v better or worse than the dvom. You can test this by sending a known REGULATED 0-5 volt input to a datalogit AN input and read it as volts from the log. Then measure the source with your dvom. If either results in a +- from the source, it is the source of your voltage drop.

 

So the Techedge readings are off?

 

No the TE readings to the datalogit are correct within .1 AFR whether or not the Gauge is connected but there is a difference (as high as +- .4 AFR most often +-.2 AFR) reported between the 5301 AFR Gauge and the datalogit log when both the TE 5301 (LD01) and the datalogit are attached at the same time. The LED gauge, not the datalogit, is the place where the reporting is off.