Dont know what the rail pressure is, I really have no way to test it as all my fuel pressure test gauges only go up to 30psi,,, I guess I could take the old Flame heater gauge and plumb it in,,,,, Time,,,, if only I had more time...... When I had trouble with it restarting after the last button shim, I pulled the fuel filter and all was good,,, running the stock filter/housing, but I should have enough parts after this order from Summit to swap out the line from the Driver side tank and replace the housing with a spin on from Cummins... the FS1212 filter/seperator is what I run on all my other diesels with either 6AN or 8An line... Thinking of taking the 6AN line THat Im replaceing with 8AN line on my Sig truck with the 24v Cummins and using that line with a couple adapter fittings in place of the stock/parker grafted stuff on the 816. Laundry list of crap to get done before Im leaving for family visit in 4 weeks,,, thus I dont know if the 816 will make it too high on the list. State is also on my back about a "Wrecker inspection" but that aint gonna happen till after the first of the year also... DOT compliance requires additional lights, Just alot of time and some $ to put it all together,,, and I am really short on Time. With it acting up like it is,,, its really a back burner project for now... (BTW I did get the Holmes 750 Medium duty tow bar in,,, its sitting in the wings for instalation soon)....