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stock fuel pressure at idle with vacuum line hooked up ???

  • Thread starter Thread starter 2002BLGT
  • Start date Start date Nov 8, 2004
2

2002BLGT

Well-Known Member
Dec 18, 2003
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59
Bedford VA
Nov 8, 2004
#1
  • Nov 8, 2004
  • #1
what should it be at idle with vacuum hooked up ???? 93 lx 5.0 by the way ...
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
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Arkansas
Nov 8, 2004
#2
  • Nov 8, 2004
  • #2
2002BLGT said:
what should it be at idle with vacuum hooked up ???? 93 lx 5.0 by the way ...
Click to expand...

I'd venture to guess unless you have some fuel pressure altering mods (like a cam that pulls different vaccum numbers)...that it should be around the mid-30's with the vacuum line hooked up...closer to 38-40 psi with the vacuum line disconnected and plugged...

This is at idle...

Mine is at 39psi w/ line off...and 34-35psi with vaccum line hooked up...
 

Michael Yount

Mustang Master
Apr 10, 2002
9,039
6
79
Charlotte, NC
Nov 8, 2004
#3
  • Nov 8, 2004
  • #3
32-34 w/stock cam/heads.
 
2

2002BLGT

Well-Known Member
Dec 18, 2003
2,945
4
59
Bedford VA
Nov 8, 2004
#4
  • Nov 8, 2004
  • #4
Michael Yount said:
32-34 w/stock cam/heads.
Click to expand...


B303 cam
Y303 heads
???
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
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99
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Nov 8, 2004
#5
  • Nov 8, 2004
  • #5
Where is your current fuel pressure at on your car right now?
 
M

manpowermustang

Member
Sep 25, 2004
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0
16
Milwaukee, Wi
Nov 8, 2004
#6
  • Nov 8, 2004
  • #6
correct way of setting fuel pressure?

What exactly is the correct way of setting fuel pressure? I pulled the line, plugged it till it said the psi I wanted then put it back on. I ask because I think that I set it at 37psi with it off and plugged and when I put in on it dropped so I did it again but hiigher so when I put it back on and it dropped down it would be where i wanted it to be?? Right ?? Or did I screw this up?
 

5spd GT

"the 5.0 owns all"
Founding Member
Aug 7, 2002
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Nov 8, 2004
#7
  • Nov 8, 2004
  • #7
manpowermustang said:
What exactly is the correct way of setting fuel pressure? I pulled the line, plugged it till it said the psi I wanted then put it back on. I ask because I think that I set it at 37psi with it off and plugged and when I put in on it dropped so I did it again but hiigher so when I put it back on and it dropped down it would be where i wanted it to be?? Right ?? Or did I screw this up?
Click to expand...

Assuming you have a Kirban AFPR (other aftermarket regulators are similar)...

Turning the hexheaded nut (allenwrench style) clockwise bumps pressure up and counterclockwise drops the fuel pressure...

You want to "turn" the FP up or down with the red vacuum line disconnected and put your finger over the vaccum line while setting the pressure...most balanced combos with the right injector for the modifications like between 38-40psi w/ the vacuum line DISCONNECTED...the fuel pressure will drop when you reconnect the vacuum line..

Set your FP when your car is warmed up (operating condition) and at idle...

Depends on what mods you have to get the "right" fuel pressure...

Oh and on my Kirban it has a "locking" nut you tighten to maintain the FP and not let the setting vibrate loose...

Good Luck
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
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Nov 8, 2004
#8
  • Nov 8, 2004
  • #8
most folks set it to what they want to have at WOT (which is why the vac line is disconnected).

the way you did it, it sounds like you are trying to get it at a certain PSI with the vac hooked up, but guessing at what it will be when you reconnect the vac line. a little backwards, i think.
 
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