micah

diesel_dan helped me out at a chapter gathering Sunday by helping install my new gauges (FP, boost, and EGT). Everything looked good on the way home until about half way the FP just seemed to bleed off slowly from ~13psi all the way to about 1psi. Well I made it home at least. So is it most likely air in the fuel line to the isolator? This morning is jumped up when I started the truck, but then just slowly bled off again down to <1psi. This has to be a gauge/isolator issue, right... i mean the truck is running great.

cditrani

You probably have a leak in the line from the isolator to the gauge. The initial deflection of the isolator diaphram from the fuel pressure on the fuel side creates pressure on the gauge side, but it then bleeds off through a leak. After letting it sit, the the isolator diaphram returns to it's resting position, sucking back in the lost air, and when you start again it works again until it leaks out...

micah

yep, it was the gauge side. opened it up today and found anti-freeze in the fuse panel... I'm just glad it wasn't diesel. no problem though, got it all cleaned up and tightened down the fitting. All is well and we're back up to good readings again.