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

MAP SENSOR VACUUM

  • Thread starter Thread starter talladega500
  • Start date Start date Oct 16, 2018
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 16, 2018
#1
  • Oct 16, 2018
  • #1
I have a 1986 Mustang GT all stock, there is a white tee coming from the MAP SENSOR, do anybody know where the vacuum line connect. If I plug it the car will stall, with this off the car runs very rich.
 

Attachments

  • 1986 MUSTANG 5.0 Map sensor 01.webp
    229.4 KB · Views: 13,714
  • 1986 MUSTANG 5.0 Map sensor 02.webp
    180.5 KB · Views: 7,975

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
28,118
10,736
213
polk county florida
Oct 16, 2018
#2
  • Oct 16, 2018
  • #2
What else has been done?
 
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 16, 2018
#3
  • Oct 16, 2018
  • #3
Nothing at all, any suggestions?
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,535
21,704
234
Box behind Walmart
Oct 16, 2018
#4
  • Oct 16, 2018
  • #4
talladega500 said:
Nothing at all, any suggestions?
Click to expand...


Are you still Speed Density or Mass Air?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,361
18,107
224
Massachusetts
Oct 16, 2018
#5
  • Oct 16, 2018
  • #5
MAP sensor = Manifold Absolute Pressure = Speed density
BAP sensor = Barometric Absolute Pressure = Mass air

86-88 Cars read manifold pressure to adjust fuel/timing, while the mass air cars use the Mass air meter to directly sample it and use the BAP to reference atmospheric pressure to calculate density.

If the OP's car is still speed density, that port needed to be capped. Should be a direct line run from engine manifold to the sensor. If the car's been converted to mass air, you'll need to remove the line from the sensor and cap the vacuum line to the engine.

I bet there's other issues going on as well
 
Last edited: Oct 16, 2018
Reactions: 89ripper and Noobz347

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,535
21,704
234
Box behind Walmart
Oct 16, 2018
#6
  • Oct 16, 2018
  • #6
Mustang5L5 said:
Other way around.
Click to expand...

I saw it before you did. LoL
 
Reactions: Mustang5L5
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 16, 2018
#7
  • Oct 16, 2018
  • #7
Noobz347 said:
Are you still Speed Density or Mass Air?
Click to expand...
Speed Density
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,535
21,704
234
Box behind Walmart
Oct 16, 2018
#8
  • Oct 16, 2018
  • #8
talladega500 said:
Speed Density
Click to expand...
That sensor port goes directly to the manifold and nowhere else. It's the last place you want to splice into for a vacuum source.
 
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 16, 2018
#9
  • Oct 16, 2018
  • #9
Noobz347 said:
That sensor port goes directly to the manifold and nowhere else. It's the last place you want to splice into for a vacuum source.
Click to expand...
Thank you very much and I will correct that.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,361
18,107
224
Massachusetts
Oct 17, 2018
#10
  • Oct 17, 2018
  • #10
Remove that fitting and run a brand new vac line from MAP to manifold. NO taps at all into that line.

Perform idle reset procedure if car is stalling and run codes.
 
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 17, 2018
#11
  • Oct 17, 2018
  • #11
Mustang5L5 said:
Remove that fitting and run a brand new vac line from MAP to manifold. NO taps at all into that line.

Perform idle reset procedure if car is stalling and run codes.
Click to expand...

That I will do and thank you very much
 
T

talladega500

New Member
Oct 14, 2018
6
0
1
Ellenwood, GA
Oct 17, 2018
#12
  • Oct 17, 2018
  • #12
That I will do and thank you very much
 
You must log in or register to reply here.

Similar threads

B
Fuel 1990 installing edelBrock intake
  • Beaker
  • Oct 5, 2026
  • Fox 5.0 Mustang Tech
Replies
8
Views
314
Fox 5.0 Mustang Tech Oct 6, 2026
Noobz347
M
Map sensor
  • miser143
  • Aug 4, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
3
Views
154
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Aug 4, 2026
AeroCoupe
J
Engine Stalling
  • josh40tay
  • Oct 20, 2026
  • Fox 5.0 Mustang Tech
Replies
4
Views
192
Fox 5.0 Mustang Tech Oct 21, 2026
JD1964
H
Engine 1987 5.0 HO vacuum hose locations
  • harryhaber
  • Jun 20, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
613
Fox 5.0 Mustang Tech Jun 21, 2025
limp
S
Fox '87 GT can't get to stay running
  • spilly
  • Mar 29, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
27
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 20, 2026
spilly
S
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?