I recently put 3 Strombergs, fuel pressure regulator and 1 1/2 dia. pressure gauge on my Poly. After about 4 min. the gauge drops from 2 lbs. to zero and stays there. Still runs fine. Two different gauges do the same thing. Any hints guys. Thanks Mick
I had one do that, I bought it brand new from Summit. Set the pressure with my old vacumn/fuel pressure gage and ditched the new gauge. Now it runs fine.
I'm looking to get a pressure gauge for my 4x2 setup soon. I want to know what's the best one that looks right? I hate to buy junk twice.
V-8 Bob Yes, both were liquid filled gauges. The first one I removed works on the bench with a little air pressure so is not broken. Someone suggested removing some of the liquid. Have not tried that. Thanks for everybodys input. I think I see a trend here. Mick
The liquid serves to protect it from vibration, it shouldn't affect the way it works or doesn't work.
Remove the plug and completely drain the fluid. The gauge should then work just fine! Been there, done that.
The liquid filled gauges when cool have atmospheric pressure in them. When they warm up the liquid expands and the pressure inside the gauge is as high or higher as the fuel pressure. So they read the difference between the fuel and the case pressure. Says so in the sheet that comes with the gauge. Take out the rubber plug and drain the fluid. Or just look at the gauge when you first start the engine.
I am having a problem with my liquid filled fuel pressure gauge. I run a mechanical gauge. The local speed shop was thinking that was the problem, and that a electrical pump would provide a more constant pressure. This happens when the car is started, so it should not be an atmospheric pressure problem as the car is not warmed up yet, and still acts the same when cold or hot.
It will happen with mechanical and electric pumps. Remove the fluid and the problem should be solved.
According to Dickster... the ones he sells are the bomb.com and don't fail. Might pm him, I bought one but have yet to run it. They are liquid filled, but don't pull the plug on the back!!
V8 Bob and Gas Pumper are correct. I went through the change of life and finally googled "fuel pressure drops as engine warms up" or something like that. Google sent me to a couple of forums that discussed liquid filled gauges. Hey- they're more expensive, so I figured they must be better, right? I just set mine before the engine warms up and then pay no attention after that. Good luck with your project.
I did not get any info with my liquid-filled gauge many years ago, but your explanantion makes sense. It acted the same on a test stand or in a vehicle, mechanical or electric pump. I was about to pitch my beautiful chrome plated POS gauge when a slightly older and mucho experienced flathead expert (Rumbleseat) said to just get rid of the fluid. Presto-whamo, problem solved.
I got to admit, I just went thru this and thought my pump was giving out , but the engine kept running fine. So Then I Read The Instructions
What I know is when it's cold the liquid gets thick. When I run it for awhile and the area gets warm the gauge works fine.. I believe it a temp. issue..Now that the weather is warmer no issues at all.. Moon liquid filled..0 to 15 pse.. Duane.
Well I took V8 Bobs advice and drained all the liquid out. Now works fine. Not sure how accurate but at least I have a indication. My appreciation to all who responded. HAMB guys are the greatest. Thank You Mick
I did not buy a liquid filled gauge just to drain it. Guess I will just live with the problem. Funny, my friends don't have this problem on there cars. Does any body know just what kind of liquid is in gauges? Just incase my leaks out somehow.
I have had a Moon liquid filled and now I have one from Dickster. The Moon gauge worked when it wanted to and the one I got form Dickster only shows a reading after I shut the engine off. A buddy also has one from dickster and his works just fine. The only difference is he has a electric fuel pump and mine is mechanical. whats up with that??
Installed a new liquid filled fuel pressure gauge, showed 3 lb. warmed up and went to zero, drained the fluid now shows 4 to 4.5lb. works fine. I'm a believer, ditch the liquid!
Copied and pasted.... In a liquid-filled gauge, the fluid fill effectively dampens system pulsation, making the gauge pointer easier to read. Likewise, humidity and moisture pose problems for dry gauges. Condensation can make a gauge difficult to read or, in some cases, can cause failure due to icing. The liquid fill (Glycerin) has no effect whatsoever on pressure readings. The glycerin dampens like a shock absorber the needle movement from shock.
Beg to differ. Add a bunch of heat and a sealed Glycerin filled mechanical gauge will read low. Had more than one myself and can even find mention of it in some manufacurers literature.
Couple points to consider here. The glycerin used in the gauges is a viscous fluid and the cooler/colder the environment the gauge is in, the thicker the liquid becomes. Yes, the glycerin does an effective job of dampening the needle movement, but the gauge itself needs to be in a warm environment. Another point is to use a gauge so that around 50% of the gauges total range is where you expect the normal pressure will run. Using a 0-50# gauge to try and read 2-3# is an example. It sounds like a 0-5# gauge will work with OP's car. A better alternative to liquid filled gauges on a pulsating process like a fuel pump output is a snubber. They are sintered metal in a fitting that mounts between the gauge and the end of the process line. They dampen the pulses no matter the environment hot or cold. Last point is to use a quality gauge. Cheap gauges are not accurate and their actual readings can be way off.