• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Installed vacuum gauge

  • Thread starter Thread starter Grn92LX
  • Start date Start date Mar 4, 2004

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Mar 4, 2004
#1
  • Mar 4, 2004
  • #1
I put a new vacuum gauge in my car tonight. I had one in 2 weeks ago but sent it back cause it was bad. At warm idle I get about 15. What I don't understand is why it will NOT go to 0 @ wot?? It goes to about 3-4. Is it possibly I have a vacuum leak? Before I put the gauge on, it read about 3-4 in the box. Is it possible this ones broken too?? Its an autometer gauge.

Mike
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Mar 4, 2004
#2
  • Mar 4, 2004
  • #2
i think it should go to zero. the gauge should read 0 when disconnected. sounds like you need a new one or recalibrate that one. or just subtract 3-4 inches when you read it. LOL J/K.
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Mar 4, 2004
#3
  • Mar 4, 2004
  • #3
The 3-4 inches at WOT represents the restriction or pressure drop across the TB and intake manifold.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Mar 4, 2004
#4
  • Mar 4, 2004
  • #4
Jrichker, thanks. i did not think vac should zero out at WOT, but was not sure. i know i get close, but normally at WOT, im lookin at other things instead of the gauge.

main point was that at rest, the gauge should zero (i.e., while in the box). still sounds like a bad gauge (to me).
 

88stangmangt

Active Member
Nov 25, 2003
2,332
1
48
Stafford,VA
Mar 4, 2004
#5
  • Mar 4, 2004
  • #5
mine read 0 when disconnected and off.
 
8

87AODGT

Founding Member
Jan 6, 2001
373
1
19
Toms River, NJ
Mar 4, 2004
#6
  • Mar 4, 2004
  • #6
yea, it should read 0 because it's at normal atmosphere when everything is off and/or the gauge is disconnected
 
You must log in or register to reply here.

Similar threads

Mustang II 4 cyl gear hunting and possibly messed up vacuum system
  • oesterreicher
  • May 31, 2026
  • 1974 - 1978 Mustang II Talk & Tech
Replies
11
Views
351
1974 - 1978 Mustang II Talk & Tech Jun 14, 2026
manicmechanic007
D
Engine 85 GT Backfires through Carb
  • DienstXIV
  • Oct 3, 2025
  • Fox 5.0 Mustang Tech
Replies
19
Views
749
Fox 5.0 Mustang Tech Oct 7, 2025
85GTStangGuy
M
Engine Themostat
  • Mindseye007
  • Jan 30, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
21
Views
812
Fox 5.0 Mustang Tech Feb 1, 2026
86HO5.0
8
Engine Random Misfire at idle.
  • Gulftown980x
  • Jul 29, 2026
  • SN95 4.6L Mustang Tech
Replies
11
Views
318
SN95 4.6L Mustang Tech Jul 31, 2026
squeak93
Alternator not charging
  • SchwarzStock
  • Jul 6, 2026
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
2
Views
122
1965 - 1973 Classic Mustangs -General/Talk- Jul 19, 2026
SchwarzStock
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?