Help: Vacuum Gauge

[Wicked 3800 V6]

Hey guys!!! Give me some help here.
I just installed a 0-30 (going clockwise) Faria Vacuum Gauge. I have concerns, and since it's my first time with a vacuum gauge, I don't know what to expect. So here goes, please answer what you can.
Caveat: Don't tell me that I shouldn't have a Vac gauge, I'm keeping it. Unless you really feel that way.

Here's what it does:
Car off: sits at 24.
Idle -- Ticks rapidly (sweeps) from about 10 beyond 30 to the 0 peg (from behind).
Lightht throttle, ticks rapidly from 25-30, or 30 to 5 beyond 30.
Mid throttle: somewhere fixed (not tick / sweep) from 27 to 24.
Max throttle (and I tried this up to 4500 and 5000, separate occasions, going like 50 (5k in 2nd) and 70+ (4.5k in 3rd): Pegs no higher than 24.

1. I installed it (skipped the light for now) with the provided tubing (6ft of white stuff). Taps like this: Nut, tube, crush thing, nut, and all that slips over either the back of the gauge or the vacuum Tee. Problems here?

2. Problem with the gauge? Is it reading backwards (I don't know how it's supposed to perform)

3. Where I tapped it: On the pass valve cover, there's this bracket that juts out and holds god-knows-what device, with two vac lines and some wiring. I tapped the farther passenger one, got the tick/sweep, and then chose the driver side (of this device) line, which also runs to the throttle body). No difference in response. Have I tapped the wrong line? Or could there be a leak at the tap?

4. Vac leak somewhere else?

5. Engine problems, needs tune-up, etc? I just replaced my PCV (routine maintenance, eh?), perhaps I didn't tighten it down enough?

Anyway, I'm just looking for feedback here. Darn thing is loud when it slams against the 0-peg. Hoping to find someone with Vac gauge experience, or hear from the folks who have blowers.

Thanks guys!
-Rob

[John_D.]

<blockquote>quote:</font><hr>Originally posted by Wicked 3800 V6:
...since it's my first time with a vacuum gauge, I don't know what to expect.

Car off: sits at 24.
Idle -- Ticks rapidly (sweeps) from about 10 beyond 30 to the 0 peg (from behind).
Light throttle, ticks rapidly from 25-30, or 30 to 5 beyond 30.
Mid throttle: somewhere fixed (not tick / sweep) from 27 to 24.
Max throttle (and I tried this up to 4500 and 5000, separate occasions, going like 50 (5k in 2nd) and 70+ (4.5k in 3rd): Pegs no higher than 24.<hr></blockquote>

My gauge rests at zero, idles around 20, doesn't tick or float at all, runs about 10-5 at mid throttle, nearly zero at wot.

Zero is at the top, vacuum is on the left side, boost is on the right.

2. "Problem with the gauge?"
Maybe. It shouldn't be sitting on 24 with the car off. The insides may have rotated...?

3a. "Have I tapped the wrong line?"
Maybe. I tied mine into a pencil thick plastic line coming from the tb, going back to the pcv I think...
3b. "Or could there be a leak at the tap?"
A leak at the tap would probably give a very low reading on the gauge, instead of the other symptoms.

4. "Vac leak somewhere else?"
This would probably give a slightly lower reading, and you would probably notice a variation in the idle.

5. "Engine problems, needs tune-up, etc?"
A ticking vacuum reading could indicate a valve not opening fully or at the correct time (a collapsed lifter). You would probably notice a corresponding miss in the idle.

Sounds like a bad gauge.

Test the vacuum signal with your fingertip over the end of the hose. Should be steady. Strongest at idle, weaker as you open the throttle. If the vacuum feels right, sounds like the gauge. If the vacuum feels wrong, you might want to find another line to tap.

The odd reading with the car off makes me think it's the gauge.

[Wicked 3800 V6]

Update: the gauge is a POS. Not sure if it's Faria, or the guy selling it ... whatever, best $9 I ever spent. When I tap the gauge, the reading pointer moves all around.

I unscrewed the line from out of the gauge, put my finger on it. It sucks my finger to it, but there is a DEFINITE PULSE to it. Chirpchirpchirp or swishswishswish or pishpishpish. Not a steady suck, but a rattatatatatat. Increases with engine speed. Do I have the wrong vac line (haven't tried switching yet, I'll wait for a better gauge I guess)?

Thanks, and your response was a HUGE help John D

-Rob

[John_D.]

<blockquote>quote:</font><hr>Originally posted by Wicked 3800 V6:
..there is a DEFINITE PULSE to it. Not a steady suck, but a rattatatatatat. Increases with engine speed. Do I have the wrong vac line...?<hr></blockquote>

Should be steady, unless you have a big cam, an ignition miss, or a bad valve/lifter.

Maybe pull another line and do the finger check, see if you get the same results.

If you still get the ticking vacuum signal, you may have something going on with the engine. Some of the older Chilton manuals used to come with diagrams of different vacuum readings and possible problems that went with them. If you want, I'll see if I can find one around here somewhere.