Best fuel pressure sender/reading, before or after fine filter?

Jeff Blakeslee wrote:

Paul, 

What flight display or instrument is the sender connected to, and what sender are you using?

Jeff, It is a VDO sensor 150 PSI going into the MGL panel for my two before the filter and VDO (have to look at pressure range) going into another MGL panel for my after the pressure sensor. Pretty basic setup on my two different aircraft.

Jeff Blakeslee wrote:

Paul, 

What flight display or instrument is the sender connected to, and what sender are you using?

This is for the before the filter reading 70 PSI with a VDO 150 PSI sender

Jeff Blakeslee wrote:

Paul, 

What flight display or instrument is the sender connected to, and what sender are you using?

This is for the after the fine filter 80 PSI VDO sender which appears to be reading correctly about 40 PSI. If you notice the OHMS are 200 for each. I just copied the 150/70 reading from the 80/40PSI assuming the 200 OHMS was correct. No specific guidelines from VDO on this. Maybe you need to measure the OHMS before you put it in for this setting?

Paul

I’m not familiar with MGL panels or the resistive VDO senders, but your setup is off somewhere.  I see that some vendors sell a specific VDO 150 psi resistive sender for the MGL, specifically, VDO part number 360-004.  Unfortunately, as you say, there is no information published about the ohm range for these senders.

I’m not sure which specific sender you have, but maybe you could call MGL and get help with the setup.  Also, typically you need to define an ohm RANGE representing zero to full scale readings. The screenshot you posted only defines one end of the range, and it’s not clear to me which end - again maybe MGL can clarify this.  If you can’t get help from MGL, you could temporarily remove the VDO sender and screw in an analog gauge to see what the real pressure is with one, and then two, pumps running.  This would give you three data points:  0 psi with pumps off, single pump pressure, and two pump pressure.  You could then calibrate the sender to best match these data points by adjusting the ohms value in the MGL. It’s not the preferred method, but it might get you pretty close.