Installing A Fuel Pressure Gauge

7991LXnSHO said:

So I am fairly sure I have a gauge just installed where the Schrader valve was. What is the issue and can I fix it with hard fittings right in the area rather than with the remote line? @jrichker
@madspeed How is it a fire problem more than a bike tube stem is already?

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Those liquid filled gauges on the schrader valve can break and you get the fountain of gas spewing out on your hot engine.

Ask me how I know that too

mikestang63 said:

Those liquid filled gauges on the schrader valve can break and you get the fountain of gas spewing out on your hot engine.

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So it's safe if it's not a liquid filled gauge?

The liquid in most liquid filled gauges is glycerin, a member of the alcohol family. Like most alcohols it is flammable It is used with gauges because it does not flash fire or explode with directly exposed to oxygen. It has a slightly thick consistency which helps dampen gauge fluctuations due to vibration. It also has some lubricating properties that make it a good choice for gauges and clockwork type machinery.
See http://www.sbioinformatics.com/design_thesis/Glycerol/Glycerol_-2520Properties&uses.pdf for more information

The only hose suitable for use with fuel pressure gauges is a stainless steel braided hydraulic hose. The hose needs to be routed away from chaffing, rubbing or resting on the exhaust system. It should be secured with Adel (cushion) clamps to keep it in place and away from heat or rubbing. This is old stuff for those of us who have worked on aircraft, but not to most auto mechanics.
Use Adel camps that are fuel resistant: look for -DF or -DG as the last two characters in the part number. These are oil & fuel resistant.

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More info on Adel calms see http://www.aeroelectric.com/articles/adel.html

Purchase Adel clams from: http://www.aircraftspruce.com/catalog/appages/ms21919clamps.php

My first post in this thread has links to all the plumbing hardware needed for a fuel pressure gauge installation.

Is that if you leave the schrader valve installed with the gauge? The previous owner installed a gauge where the valve was, but the schrader itself is no longer installed. The original gauge failed a while ago so I went with a decent 0 - 100 psi liquid filled gauge. Its been on for a few years, but I do worry about vibration and the offset weight hanging from the hard line causing the hard line to fail.

How did yours break Madspeed? I'm worried now.

jAEded said:

Is that if you leave the schrader valve installed with the gauge? The previous owner installed a gauge where the valve was, but the schrader itself is no longer installed. The original gauge failed a while ago so I went with a decent 0 - 100 psi liquid filled gauge. Its been on for a few years, but I do worry about vibration and the offset weight hanging from the hard line causing the hard line to fail.

How did yours break Madspeed? I'm worried now.

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you remove the schrader valve and screw on the adapter and the gauge. I really see no reason whatsoever to need a gauge on the fuel rail. You only need to know thr FPR when you are testing, or changing the FP.

Either have a remote mounted one on the fenderwell or cowl, or just use a FPR test gauge when you need to adjust it.