I have a brand new Stewart Warner electric fuel pressure gauge that I hooked up about a month ago. When at idle it only shows 20 PSI of fuel pressure. WHen I hook up my manual test gauge it shows about 41-42. Could there be something wrong with the gauge?? I have the gauge wired in serious with the shift light gauge, could this be the problem? Should I use a seperate wire just for the fuel pressure gauge??

 

Is that supposed to be 'series'?

Anyways...if you wire two elements in series, they will be splitting the voltage according to Ohm's law...if you have elements wired in parallel with the battery they "see" whatever voltage it was designed to operate at (~12.5V, the voltage of the battery).

*I do not know how the gauges work or how they are designed to operate, but it seems like it would be designed to operate at a certain voltage, and it is not getting all that it may need if that is the case.

 

from what u said it appears that it is pickin up your tach signal. the fp gauge needs to run to a sender

 

The gauge is running to a sender. I will try to run a seperate wire for the fuel gauge only to see if that fixes it.

 

I have a autometer electric fp guage. I wires mine to the ignition/bat fuse and wired the light to the dimmer fuse. So far everything is good