fuel pressure guage

[76bonanza]

I got a liquid filled fuel pressure guage because I thought it would be more accurate. It is not, once it gets hot it will not read fuel pressure correctly any more, I have come to find out this is the way they are once they build up pressure. My question is mine has a rubber plug in it if I remove it the liqiud comes out. If I drain it all out will it still read right or are the calibrated to only work when the liqiud is in them?

thanks

[glock35ipsc]

The liquid is there to keep the needle from bouncing around on lump-camed vehicles.

[SactoJim]

I have one mounted on my pressure regulator and it seems like it doesn't read right when it heats up. It actually reads very low and sometimes 0 pressure, but the truck still runs fine.

I thought I might have another problem, but now that I've seen this.....?

Can anyone else shed some light on this?

[glock35ipsc]

For both of you guys.... are your gauges mechanical or electric? When I had the blower on my 2003 Chevy, I had an electrical gauge inside but never had the type of problem you guys are having.

[76bonanza]

these are mechanical and mount in the engine compartment. As it was explained to me when the liquid heats up pressure builds in the guage making it read low or not at all. The more pricey units have an air bleed in them to relive this build up but the cheap 15.00 one I have does not.

[SactoJim]

Boy, if there is some truth to this, it sure makes me feel better. I was thinking something else may be wrong.

[70c10]

My gauge bounces like crazy and I can't even read it!

[76bonanza]

Well jim I talked to at least 12 local rodders that use them and they all said the same thing and have read several things on the internet. Some of the discriptions on sites like summit for the non liquid ones even say good readings at any temp. Any way I ran my friends non filled one and it always read right. So I think I will be switching.