Fuel pressure help

[Fisher]

I have a new Holley Blue pump and regulator which i installed today. Issue is 2 gauges installed , the one at the carb reads 1.5 lbs less than the one on the cowl? The cowl is 7.5 and the carb 6. Which is correct? Both are tapped at the same place.

 

[Dana67Dart]

Neither! being a bit sarcastic but unless the gauges are calibrated they will only be close. eliminate the engine compartment one if you need to keep a watch while driving. will 1.5 psi make or brake your fuel system?

 

[brian6pac]

Your autogauge is not at 0 it's way low so I would say that gauge is junk.

 

[pishta]

There is a vent on top of the guage. The hotter it gets, the lower it reads unvented. you can unscrew the brass screw on top (?) to vent then return it but there were posts that said drill a .020 in the screw itself to permanently vent the guage. See if this fits your guages description. I know the rubber boot is the vent on top. venting should return you to zero.

found this on Moparts. Note red test gauge and yellow unfilled against unvented liquid filled gauges over heat.

 

[Fisher]

Thank you for the replies. I am going to remove the Engine compartment one and leave the cowl one in play.

 

[Dana67Dart]

Your autogauge is not at 0 it's way low so I would say that gauge is junk.

good catch. How often we all miss the obvious.

 

[pishta]

good catch. How often we all miss the obvious.

its not junk, just needs its ears popped.

 

[brian6pac]

Good call, never thought of that

 

[Fisher]

I took it off the car and plugged the hole, then popped the little rubber plug off it and the gauge sort of zeroed itself. I will leave it off.