I have just installed a fuel pressure gage using a high pressure SS braided flex line. This line is transmitting engine mechanical noise into the cockpit area - LOTS of noise.
Anybody have any suggestions for eliminating the noise? No, I am not going to use an isolator and switch to an electric gage. I did a search here and on the internet but can't find any definative answers.
Two possibilities come to mind: One, make up a 4" - 6" section of only rubber hose (diesel resistant) and install that between the pump and the SS line or two, clamp the flex line on to the engine or the shock tower using steel clamps and not plastic Tyraps. Clamping it on to the engine is almost impossible unless I lengthen the hose. The shock tower is convenient but still a PIA.
There is a Parker dealer not far from me so may drop by there this morning and see what their experts say about this.

 

Electric gauges don't use isolators. You could either use an isolator on the hose you are currently using or get a rubber hose between the fitting and the steel hose to dampen the harmonics.

 

Do you have a needle valve or "snubber" installed inline? The hose itself is noisy?

 

Oops, wrong terminology. You are right.

No needle valve or snubber is in the line. I have one but thought I would try it without first and see if the needle bounces or vibrates. The needle is rock steady so presume that the noise is coming from the hose. Although the hose is flexible it is quite stiff. The noise I am hearing is a loud mechanical noise that changes pitch according to the engine speed. I can describe it as sounding like taking a large screwdriver, placing the pointy end on the engine and your ear on the handle, except multiple the volume considerably. Disconnect the line at the pump and the noise goes away. Move the line around when the engine is running and the noise changes.

 

Try taking a foot or so of rubber fuel line that will fit over your braided line snugly, split it length wise and install over the outside of your braided line, somewheres where it is easy to get at and preferably in the engine compartment.

retooc

 

The needle valve will solve your problem. Even though the gauge is steady, there are still pulsations that are being transmitted through the hose to the gauge itself.

 

Thats what I was thinking, the "hose" isnt making any noise. If it were a long single peice of sheet metal (dipstick like) I would believe it. You really should have a way to stop the fuel supply to the gauge anyway.

 

Problem solved. I went to Parker and bought a 12" length of 250# working pressure, 1000# burst hose. There is no steel braid in it. I coiled this up and installed it between the pump banjo fitting and the braided hose going to my gauge. All the noise has gone away. The only thing that I am concerned about is how this hose will last with diesel. I read up on the specs in the Parker manual and it is good for all kinds of chemicals including gasoline and under hood use, but the words "diesel" was not used. The Parker resident engineer (not the guy behind the counter) assured me that it will be OK for diesel.