I've been thinking about doing the same for my pre-filter reading.
Nice job.

Ed

I added the pic to your post.

PS:
If those readings are at idle, when was the fuel filter changed last?

 

Thanks. I tried to do it, but couln't figure out how...

p.s. It's been a while. Should I change it again? 15psi pre, 12psi post?


Hey, did you see the yellow wire in the picture, to the left? It's the APPS re-wire for my "Searching" transmission. That fix worked well. I got the directions for the re-wire from Joel at ATS diesel in Colorado.

 

Yup I think the filter is due.
There should be very little difference between the pre and post filter readings.