Have an Isspro Mechanical FP gauge in the cab. It is hooked up using a needle valve off the bottom of the fuel canister. Fired up this morning after not using the truck since Friday and went to work. A mile from home, I looked at the FP gauge and it read "0". Heart stopped, jerked with the pedal and downshifted, all of a sudden FP goes to normal. Go to McDonalds drive thru and shut down to order and notice that FP does not go to "0". Start back up, and FP is goes to normal (takes a little longer to get there). Get to work and shutdown, FP again does not return to "0". Get fuel filter changed after work, FP still does not return to "0" after shutdown. Get home, shutdown and open needle valve a little more, FP still does not return to "0". What next?

Thanks,
~Rob

 

Open it a whole bunch and see if it will return to Zero.
Then try to close it and readjust it for the Buzz-B-Gone setting.

 

Had the same problem with mine. After driving the truck for a while and then shutting it down, the gauge waould still read about 2-3 psi. So I drove it for a while and then shut it down, then I loosened the fitting that connects the tube going to the gauge (either end), in order to release the trapped pressure, allowing the gauge to return to zero. Then I tightened her back up and its returned to zero every time since then.
Hope this helps.

 

Don't know what you are using for hose/tubing but it sounds like it's kinked.

 

I tried to open the needle valve all the way, but that did not work.
Next step is to disconnect the fuel line from the needle valvel to the gauge (at the fuel canister end).

Infidel, this pic is from Moose10's gallery, but the hose I am using is very similar to this. I can see no visible kinks. The gauges were instaled 4-5 weeks ago and I have not had this issue happen until today.



Thanks,
~Rob

 

It would be pretty hard to kink hose like that. My only other thought is maybe the hose you used wasn't diesel rated. I've seen gasoline hose melt down with diesel, the layers inside separate and can block the flow. You can't tell there is any damage from the outside.

 

Rotated the gauge about 90* in an attempt to remove it from the pod to purge any air from it, I had just shut the truck down and it read about 10 psi. Soon as I rotated the gauge, it dropped to about 1 psi. Me believes Infidel's kink theory is correct. Will take it to the install shop in the next few days to get fixed.

~Rob