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

Is this normal??????????

  • Thread starter Thread starter mustangfan1990
  • Start date Start date Feb 11, 2008

mustangfan1990

New Member
Jul 17, 2005
505
1
0
Lenoir, North Carolina
Feb 11, 2008
#1
  • Feb 11, 2008
  • #1
I hooked up my fuel pressure gauge a minute ago and when I did. I just turned on the key to start the fuel pump and the guage went to 40. Thats with the engine not running. Then I crank it and it drops to 35 when I rev it and then at idle it goes back up to 40. I would think this is normal drop when I rev it because the fuel injectors are opening up more so the pressure drops I just wanted to see if those numbers sound right..
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,145
17,839
224
Massachusetts
Feb 11, 2008
#2
  • Feb 11, 2008
  • #2
They sould right, but with your mods you really should be condering a custom tune vs messing with the fuel pressure. You are running an FMU with the 24#ers right?

I would personally ditch that setup for some 42's and go get a custom tune.
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Feb 11, 2008
#3
  • Feb 11, 2008
  • #3
Assuming your numbers are with the blower as well, your numbers are very low.

I agree, if you have the heads, cam, and intake plus the supercharger, the injectors need to flip-flop positions.

24 - 42
 

mustangfan1990

New Member
Jul 17, 2005
505
1
0
Lenoir, North Carolina
Feb 12, 2008
#4
  • Feb 12, 2008
  • #4
5spd GT said:
Assuming your numbers are with the blower as well, your numbers are very low.

I agree, if you have the heads, cam, and intake plus the supercharger, the injectors need to flip-flop positions.

24 - 42
Click to expand...

The blower isnt on yet.....I am still waiting on it to get here. Those are my numbers with HIC setup that I have. I will get 42s and a custom tune but I have to run with the FMU til I get the money to that.
 
You must log in or register to reply here.

Similar threads

7
Engine Random hanging idle
  • 706 Saleen
  • Feb 11, 2026
  • Fox 5.0 Mustang Tech
Replies
9
Views
422
Fox 5.0 Mustang Tech Feb 19, 2026
86HO5.0
8
D
Fuel Erratic Fuel Pressure 1985 GT
  • DienstXIV
  • Jan 14, 2026
  • Fox 5.0 Mustang Tech
Replies
16
Views
615
Fox 5.0 Mustang Tech Jan 16, 2026
AeroCoupe
I
1994 Cobra - Fuel Pressure Drops Revving at Idle
  • IconicSilverGT500
  • Apr 11, 2026
  • 1994 - 1995 Specific Tech
Replies
16
Views
360
1994 - 1995 Specific Tech Apr 24, 2026
Mcmahst
L
Engine Why won't the motor start if I have spark and fuel
  • LeviAnderson
  • Nov 20, 2025
  • Fox 5.0 Mustang Tech
Replies
3
Views
365
Fox 5.0 Mustang Tech Nov 20, 2025
AeroCoupe
D
Fox 88 foxbody no power to red and black wire at fuel pump relay
  • drod88
  • Dec 1, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
7
Views
299
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Dec 2, 2025
Mcmahst
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?