• Mustang Forums
  • 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
M

mustangjoe02

Member
Apr 29, 2011
84
0
7
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
5,892
514
204
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.
 
M

mustangjoe02

Member
Apr 29, 2011
84
0
7
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.
 
M

mustangjoe02

Member
Apr 29, 2011
84
0
7
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
3,125
81
99
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.
 
M

mustangjoe02

Member
Apr 29, 2011
84
0
7
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
514
204
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.
 
M

mustangjoe02

Member
Apr 29, 2011
84
0
7
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
204
Houston Texas
Sep 4, 2011
#10
  • Sep 4, 2011
  • #10
So what are the results of the key cycling test?
 
You must log in or register to reply here.

Similar threads

F
2004 Mustang GT – Fuel Pump Not Priming
  • Fayio
  • Apr 22, 2026
  • SN95 4.6L Mustang Tech
Replies
7
Views
176
SN95 4.6L Mustang Tech Apr 27, 2026
n0v8or
N
B
'03 GT Fuel Pump/Pressure/Delivery Issue
  • Brodach
  • Oct 21, 2025
  • SN95 4.6L Mustang Tech
Replies
8
Views
815
SN95 4.6L Mustang Tech Oct 31, 2025
gkomo
Fuel Damper, 2003 Mustang GT
  • bmmckl
  • Dec 19, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
0
Views
161
1996 - 2004 SN95 Mustang -General/Talk- Dec 19, 2025
bmmckl
S
Fuel rail help
  • stang9150
  • Mar 3, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
10
Views
254
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 5, 2026
stang9150
S
D
Fuel pump upgrade
  • dkrupp79
  • Jul 7, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
4
Views
225
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 10, 2025
Scrapla347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L 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?