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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

injector/fuel pump

  • Thread starter Thread starter mustangjoe02
  • Start date Start date Sep 2, 2011
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mustangjoe02

Member
Apr 29, 2011
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Sep 2, 2011
#1
  • Sep 2, 2011
  • #1
just wondering, if you have upgraded injectors, do you have to upgrade the fuel pump?
 

wmburns

SN Certified Technician
Aug 14, 2009
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Houston Texas
Sep 2, 2011
#2
  • Sep 2, 2011
  • #2
How much HP are you making? How much HP do you plan to make?

The fuel pump should be sized to match. A needlessly large fuel pump can cause it's own set of problems. The symptom is different depending upon return or return-less fuel system.

Not a lot of information to go on. Not proud of your ride? Sure seems like it due to the lack of detail/effort in the thread.
 
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mustangjoe02

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Apr 29, 2011
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Sep 3, 2011
#3
  • Sep 3, 2011
  • #3
im just wondering because im pretty sure i have 24# injectors (on the car when i bought it) but when i tune for them, its like its harder to start the car on a cold start. however runs fine after that.
 

Maxpowers

Member
Sep 9, 2009
859
2
19
Pittsburgh, Pa
Sep 3, 2011
#4
  • Sep 3, 2011
  • #4
That's a bad tune. If the car runs fine and has power after it starts, then it obviously isn't the fuel pump.
 
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mustangjoe02

Member
Apr 29, 2011
84
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Sep 3, 2011
#5
  • Sep 3, 2011
  • #5
arent light blue injectors usually 24#? ill know for sure when i change spark plugs next week and look at them closer
 

trinity_gt

10 Year Member
Jan 31, 2003
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Canada
Sep 3, 2011
#6
  • Sep 3, 2011
  • #6
An 02 GT pump is more than capable of working with 24# injectors.

How are you tuning for them? What tool are you using?

The plugs won't tell you much. They'll most likely be white-ish or tan because the PCM operates in closed loop most of the time. The amount of fuel delivered through the 24s during these conditions will be the same as that delivered through 19s. If you've got problems starting when cold it's likely the "tune" is still incorrect as Maxpowers suggests.
 
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mustangjoe02

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Apr 29, 2011
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Sep 3, 2011
#7
  • Sep 3, 2011
  • #7
using my sf3 sct. but that helps alot. thanks guys
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
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Houston Texas
Sep 4, 2011
#8
  • Sep 4, 2011
  • #8
mustangjoe02 said:
im just wondering because im pretty sure i have 24# injectors (on the car when i bought it) but when i tune for them, its like its harder to start the car on a cold start. however runs fine after that.
Click to expand...
Hard start could be fuel pressure leak down. Try cycling the key on/pause/off several times without cranking. Does this improve starting? If so, suspect fuel pressure is leaking down between starts.
 
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mustangjoe02

Member
Apr 29, 2011
84
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Sep 4, 2011
#9
  • Sep 4, 2011
  • #9
how would you know for sure if thats what it was? how to fix also?
 

wmburns

SN Certified Technician
Aug 14, 2009
5,892
514
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Houston Texas
Sep 4, 2011
#10
  • Sep 4, 2011
  • #10
So what are the results of the key cycling test?
 
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