dodgeguy71

Got my new Dipricol fp guage on last week. Had some air in it, not to much but the gauge would just keep building pressure, up to around 25psi. When you went to wot it would just stay where it was at......great lift pump?? So I loosened the fitting at the isolator and bled air out there. Next day driving it went up to around 14-15 psi and would drop down to around 9-10 psi pulling a hill mashed to the floor with 3000#'s behind me. So I think that's weird? Well, I better get the rest of the air out. So tonight with the help of my wife we got the tube filled with coolant.

I start the truck and idle up and it goes to 15psi, great I think, rev it a couple times and the fuel pressure keeps going up??? So around the block we go, wot and fuel pressure stays at 25psi, has not built up anymore than that, but will not go down. Shut off the truck and it stays at 25psi.....now filling the tube and getting all the air out was a pain, used a seringe for animals and it was ok. But why on earth is my gauge going crazy like this? Seemed to work better with some air in it up at the guage? Any thoughts as to what I should do? Induce air on the gauge side?? It is tapped into the injection pump at the shrader valve fitting(removed). Any thoughts or ideas would be appreciated. Thanks!

Shawn

Timberman

Good luck man. I've got a similar problem, mine is staying around 1 psi but never moves much. Post up if you figure it out.

Big Deezul

mine did the same thing untill I removed the isolator...no problems since

dodgeguy71

One thing I noticed on my isolator is a big screw, flathead type, on the fuel side of the isolator....is that for bleeding the fuel side of air? I found out that no air in the coolant side is good. Just now wondering if air on the fuel side could scew the gauge at all? Guess I just have to experiment. They did ask me where I tapped into the fuel pressure at and I told them on the injection pump at the shrader valve. Maybe I need to move it to the bottom of the fuel filter. Just hate to drain all the fuel out of the vp again......will try and post what I find...

dodgeguy71

OK, experimenting complete....for now. Gauge was showing 25psi after it has been sitting for 3 hours. The screw on the isolator, big flat blade screw, it should be on the fuel pressure side. Start the truck, after your coolant tube is full and all connected. Loosen the screw on the isolator on the fuel side and bleed the air out of the fuel side. I loosened it first and saw the gauge start to drop, then keyed on, gauge went up to about 12psi, then started to leak back down, started the engine and let the fuel run out for about 30 seconds, then tightened it while leaving the engine running. Fuel pressure at idle is around 13-15 and when I hit the throttle I have instant response on the FP gauge, keep on wacking the throttle and reving it up it would drop down to around 10 psi. Seems to be ok now, will find out final results on the drive home tonight.

So basically bleed the air out of the fuel line and isolator with that big screw on the isolator. Seems like air will play havoc on the gauge. Hope this info helps others with similar problem

Big Deezul

or just remove the isolator

dodgeguy71

Last post, test drove the beast home last night. Had 13-14 psi at idle and 6-7psi WOT. Cruisin at 70mph had right at 10psi. So seems like all is well with the fuel pressure gauge......and lift pump for now. Hopefully it poops out before warranty is up!!