Sorry, didn't have my glasses on with the small fonts. Maybe the air column in the 10" of hose was acting as a spring cushion?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I know what you mean about trying to get away without putting on yer glasses. I'm not sure how much air remained in the line but I started the car with the gauge below the IP and moved it into a much higher position to take my readings. I never intended to bleed the line but in this case an air pocket may be welcome.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

A fuel dampener device is common on petrol fuel injection systems. It is usually just a "stub" line/device which uses an air pocket to absorb the pulsations so you are probably right on the money with your guess.

I imagine the "cigar hose" serves the same purpose. Barry is probably spot on with using a capped length of hose "t-eed" into the supply to reduce the fluctuations. Wouldn't need to be much, maybe 2-3 inches maximum of the 5/16" inch line and you could probably get away with only about an inch.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Why not just use a liquid filled gauge?

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CENSORED due to not family friendly words

Crazy but I also thought it was ten feet you mentioned initially. Actually was quite surprised when I re read 10 inches. I assume it was a relatively normal piece of fuel line hose as well.

Because they do have quite a give in them. Also there are two hose pressure ratings if I remember. So I do not think you want the fifty pound rated stuff.

The low pressure hose should still be well under its safety rating or built in safety factor. I am mentioning this because otherwise someone might get perhaps the more common fifty pound working pressure stuff today and wonder why it did not work out. For all I know you might even have used the fifty pound hose and it worked.

It actually would be a great help if the poster could identify the hose he used. Many times enough information is printed along the hose length to identify it.

Even they cannot cope with the vicious spikes. In not much time the reaction to the spikes fatigue the internal tube. As we have been using even the fluid dampened ones up they still osscilate the needle. Compounding this is they are working against the additional load of the fluid dampening medium. A non dampened gauge just slams from one stop to the other was experienced.

Accidental or otherwise the contribution of the member is excelllent. It should be a permanent simple solution to a problem that has been vexing.

For more reasons than are worth listing a permanent fuel pressure gauge is worth having. Even if you only use it as an early warning device that something is failing in the fuel supply chain.

For what its worth the gauge pictured above has been teed off the fuel line between the filter housing and injection pump for a few months now without issue. The needle doesn't pulse. The pic was taken with the engine running at idle after installing an electric booster pump at the tank.

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CENSORED due to not family friendly words

The actual length used 11 1/4 inches, SAE 30R7 not for fuel injection systems made in the USA by Gates.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

Great information and sounds like the old fuel hose with far less of a pressure rating.

If the poster of his gauge is using a dampened gauge and it is working. Ether the dampening effect is better than the harbor freight versions or he may have something in his system that is helping things out.

Worse scenario would be the internal gauge tube is dealing with the spikes and the needle of his gauge is just not reflecting it. It that case it is probable that the gauge will fail at some point. Not much is absolute in life but the probability may exist.

There also exists the possibility of design differences inside the gauge housing. Compared to what we have experienced.. The harbor freight model will only tolerate the spikes for so long in service. The internal tube fatigues out but the gauge is readable usually.

The gauge used was a swagelok PIC series 4 1/2 dial 0-30 psi range fluid filled but I drained it long ago as it leaked and was not suitable for portable work. This is an indampened gauge and the same gauge I had used a year or so ago but with a 1/8 inch poly line and she was dancing. This was never intended for a permenant installation just a quick check.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10