KLR

I believe that I have a vacuum leak at the back of my Autometer boost gauge in the gauge panel beneath my stereo. When I get on the boost, I start to get a hissing sound from the gauge panel at about 8-10psi that, not surprisingly, gets worse as the boost builds. I've loosened the adapter in the picture below and replaced the teflon tape twice to no avail. When I disconnect the adapter, I can tell from blowing and sucking through it into the tube that the connection is holding vacuum and that there's no leak between the gauge end of the hose and the manifold. When I blow into the back of the gauge (the threaded part onto which one puts the teflon tape), I can also tell that the gauge holds vacuum.

Any thoughts? The ferrule is in the sealing nut. What am I missing here?

OriginalSterm

The hissing might be internal to the gauge. Maybe it's got a leak somewhere. Can you confirm what this boost gauge reads by hooking another up to your car to see if it's a bad gauge?

jimbo1111

Hook it up to a bicycle pump and see if the gauge leaks under pressure. If not. The connection/tubing is at fault.

Mike Murcia

I've started noticing a hissing in mine too. It started after I replaced my engine, so i don't know if I knocked something loose at the back of the gauge, or if my new engine is quieter and the sound was always there. I'm going to put gobs of silicone sealant around the fittings and see what the result is.

p0wp0w

I'm not sure if the VDO and Autometer are set up the same but for my VDO i had the same problem. To fix it i just took two wrenches that fit the sealing nut and adaptor and twisted in opposite directions. This closed the ferrule and clamped it tight. Make sure its not too tight to go through the nylon tubing though. Try that, goodluck!

KLR

My dash board boost gauge reading is consistent with the Autometer gauge's reading, so I'm pretty sure that the gauge is accurate. I've not hooked up a bicycle pump to see if the gauge leaks, but I have blown on the fitting on the back of the gauge and did not hear/feel any leaks in the gauge.

p0wp0w's solution sounds like it might be it, although the sealing nut and the adapter did seem to be tighted against each other pretty well. Unfortunately, I won't be able to check for a while as I just dropped the car off on Tuesday with my body/paint guy to have a dent repaired and the rockers resprayed. He's good, he's reasonable, and so, of course, he's slow.

Peckster

Good, fast, cheap. Pick two.

My favorite rule, applies to lots of things.

KLR

It is a truism. Damned economics.

MichelleJD

That's the sound of a 944 cleaning out your pocketbook

tazman

This sounds like your problem here. Once things are tightened down properly the ferrule usually stays on the tubing. To install it properly I usually slip the sealing nut over the tubing then the ferrule then push the tubing into the gauge as far as it will go, bring the ferrule down into position then tighten the sealing nut as p0wp0w said.

facboy

yup. u need to give it a good twist so the ferrule (and most likely, the 'adaptor' as they call it) compresses a bit. that way they seal tight against each other. don't go crazy though, i think a good finger twist should do it. i went berko with a wrench and destroyed the ferrule, had to buy a new one. idiot .

sm

Hey, where is this guy? I would like to call him to get an estimate for some work. Are you pleased with his work?

Thanks.

turbo944

"A giant sucking sound... "

I was going to guess it was Virginia, but you're a bit far north to hear that unless they've gotten worse..... There's a saying here in TN, it's not the wind blowing, it's Virginia sucking

I have a similar sound in mine as well, to get back on topic...will have to pull it and see what's up....

KLR

sm,

This guy works at a shop out of his home near Reading, PA. This is the first work that he has ever done for me, but he has a fantastic portfolio of work that he's done over the years for a Ferrari shop in philly. His business is primarily metal fabrication and, to a lesser degree, paint for large scale restorations (when I was in his shop last week, he had a 1929 Riley with a flathead ford, an Allard J2X with a chrysler hemi for which he'd fabricated several panels, an XKE that is being converted into a replica of the original aluminum bodied race cars, and a Devon with a 383 chevy ). PM me if you're interested in his contact info and I'll set you up.

- Neal