Fuel Pressure gauge & Powerlogger reading

[6gunn]

I've just wired up the Powerlogger to log fuel pressure and there is a difference between the two readings. The fuel pressure gauge is an Autometer with electric sending unit. Not sure if I'm going about this right, but in the .INI file for the Powerlogger, I've modified the "CustomAnalog4MinVolt" to about 1.3, and when saving that change, the reading in Powerlogger shows pretty close to the gauge reading at idle, but the difference in readings grows when I load the motor on the brake and watch fuel pressure readings. Do I need to make these changes in the .INI file with the motor off and fuel pressure at 0? Does anyone know the scaling for the Autometer electric sending unit or would that even help?

 

[6gunn]

Ok, got it figured out I think. Changed min volt back to 0.5 but also changed the max gauge reading from 150 to 100...since the Autometer sending unit is rated 0-100psi. Idle fuel pressure still shows a little different than the gauge, so which one should I trust? The gauge or the reading in PL?

 

['87 Turbo "T"]

I seem to have a similar issue. There seems to be a difference of about 1-2 pounds between my Autometer gauge & the PL. PL says I’m getting 1.9-2v & checked it with a DMM & got the same reading.

Interested if you can figure out why. Not sure which one to trust over the other. I usually don’t look at the fuel pressure doing a pull, I look at what the PL has recorded……I need to do better.

I messaged Bob & he told me to do the voltage check on the purple(signal) wire, & to make sure my grounds are good.

 

[6gunn]

Just did the first test runs since setting it up to log fuel pressure and it is pretty much dead on when adding boost psi+base fuel pressure. At a glance, the gauge(pillar mounted) shows to be pretty accurate, but t's just a glance so it could be off by a bit. I trust the logged FP more than the gauge.