More low fuel psi issues when hot

[stangman67]

So, last year i was chasing a problem with my nitrous system "surging" when in use. I found it to be my cheapo holley regulator having 6.5 psi at idle cold, and when it warmed up(the motor), it would fall to 2ish. I had a fuel psi safety switch, so it was turning on and off with the fall and sudden rise in pressure. So i took the regulator off, and was running 8-9 psi all the time, i have a holley 130 gph pump now, and never have a running out of fuel problem, but the other day i finshed an intake manifold swap, and was warming it up, and noticed my fuel gauge on the log said like 2psi.
Now i checked it again with my snap on gauge(accurate), and right off the pump running it was 2-3psi. This happens after the engine reaches operating temp. The fuel is not hot or boiling, and i have no starting troubles, i just want a constant 6psi of pressure. I dont get it. So, im looking for advice where to go next. Thanks.

 

[brianj5600]

Is the pump electric? Are either of the gauges liquid filled?

 

[iskwezm]

if your not getting pressure at the carb look for a blockage(fuel filter) or maybe a voltage problem at the pump or put a inline gauge at the pump to make sure.

 

[Rusty67]

if your not getting pressure at the carb look for a blockage(fuel filter) or maybe a voltage problem at the pump or put a inline gauge at the pump to make sure.

You beat me to it.

If you are running an electric pump, you should have a pre-pump filter to prevent the pump from geting clogged. Double check all of your filters to make sure they are free and clear. Also, move the gauge to different points in the fuel like to check and see if there is a problem area.

 

[mrmustangman357]

is your regulator mounted close to the engine? Heat may be killing the spring and letting more fuel through. it has happened before lol

 

[10secgoal]

When the motor heats up and you start to see the psi drop, feel the pump. See if it's hot also.

 

[stangman67]

its a mechanical pump. I was busy today and didnt get to look at it, but i am concerned it may be an issue with my tank not venting, so im pulling a vacuum the longer it runs. I do not have a regulator, but i never have a over fueling situation.