Faulty Fuel Pressure Guage?

[16919]

Hey guys, I just installed A set of DiPricol guages on my 01... pyro, boost, fuel press. They have only been on the truck for maybe a week and were working great until last night. It originally ran 16 psi at idle and 11 at wot. I alreagy had my vp and lp replaced on the truck about 8,000 miles ago so I'm not too worried about it going out, my FASS is going on in a few weeks. But anyway, I drove the truck around fine last night, went to a buddies, let it sit for maybe 2. 5 hours, got back in the truck and now the guage won't read above 9. 5 psi. I'm pretty sure its the guage and not the truck because I can run the truck at wot and the guage wont move up or down. It will drop down all the way when I shut the truck off, bump up to about 5 or 6 real quick when the lift pump kicks on before I start it, once the truck is on it reads 9. 5 and stays there. I dont know if it would be the Isolator or the guage itself. I'd like to get some opinions or suggestions before I tear the whole d*@% thing apart. Any help is appreciated!

 

[Nyoest]

It's probably a small leak between your isolator and gauge. I've got the same exact problem right now . Every few months I have to refill the line I guess it's time to redo it.

 

[SSabick]

I have had bad luck with an Isolator as well. That is probably the problem. Mine acted the exact same way as you are describing. Darn things are about as bad a the lift pumps in our trucks. Honestly since I have been fortunate enough to not have any lp issues yet, I would call them even more junk than the Lift pumps. I heard that Stewart Warner has an electric Fuel gauge that is supposed to be good. I may try it next. I have to admit that I am a bit nervous about an electric fuel gauge though.