Fuel Pressure Fluctuating?

[CHPMustang]

Couple weeks ago I adjusted the fuel pressure via Big Joe shim as always but now the fuel psi moved from 72 on Monday morning to 75 psi this morning

Now Monday morning was in the upper 70's range outside and today it was in the mid 60's I think,now would a 10-15 degree shift alter the fuel consistency that much causing the psi to rise similar to oil thickening as an example?

 

[firemediceric]

If you search my screen name, you'll see where my fuel pressure has been low for no known reason. Some suggest a fuel pump issue, some suggest an issue with the FPR.

I have not really done anything to correct it, as I have not been sure what to do. The pressure has gotten better on it's own.

If your interested, PM me an e-mail and I'll forward you the stuff Diesel Man sent me. You'll be interested in his thoughts on shimming the FPR. He's completely against it

 

[CHPMustang]

I've had my FPR shimmed for a couple years without an issue with only a couple of adjustments made in that timeline due to different fuel grades/types I've used.

I sent you a PM I'd like to hear your friends opinion on the mod.

 

[roosterdiesel]

When I had a shimmed stock regulator I had higher pressures on cold iron starts. More so in the winter when temps were colder. Don't know if it's the viscosity or the spring tension is stronger when cold and less with some warmth in it.


With the Aeromotive regulator I don't see the different pressures.