I have an Isspro EV fuel pressure gauge that is not working right. Pressure reads about 5 PSI low and the gauge does not go back to zero, sits at about 3 PSI. It eventually goes to zero after it sits for awhile. I have bled the line from the isolator to the gauge, checked for kinks etc. All looks good. If I burp the gauge (pull the line) it will drop to zero but as soon as I pressure it up again it starts to act the same way again. I'm beginning to think that the isolator is not working correctly, anybody have any experience with these things??
thanks

 

DRD
I have the Isspro mech. gauge, with stainless line (no isolator) and it works fine. Sounds like your isolator is not funtioning, or your trapping pressure somewhere in you line. How are you tapped into fuel pressure. On my 2500, the shrader at the vp44 is almost impossible to get good readings, with the Briar Hopper gauge, because the shrader will not open up to allow free flow of fuel. If you are hooked to the shrader ,check to be sure it is allowing good flow.

hth

 

If you're hooked to the schrader, aren't you supposed to remove the valve core? ???

 

I have the early style fuel filter housing with the 1/8 NPT connections on top. Tied in post filter.

 

I'll echo what others have said: It sounds like the isolator isn't working quite right. Keep in mind that if your isolator hasn't been built for the gauge that you are using it on, you may get some inaccuracy out of it as well. We tried using a couple different isolators with IssPro gauges and found that the accuracy just wasn't there.

Rod