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

Fuel Fuel pump constant priming

  • Thread starter Thread starter BuckleSwab
  • Start date Start date Aug 21, 2020
B

BuckleSwab

New Member
Aug 21, 2020
4
0
1
Georgia
Aug 21, 2020
#1
  • Aug 21, 2020
  • #1
Hey everyone, I'm new here. I've lurked around withoung being a member and have gotten a lot of help from here but I've been having some trouble and was hoping to get some advice/help. I have a stock 89 and lately my fuel pump priming has been taking longer and longer to fully prime and engage but today i tried to start it and it is just constantly priming, primed over 20 minutes until my battery died on me. Tried pumping the gas, turn it off and on but it never engaged so it won't turn over. What should I look for to fix the issue? It's getting fuel to the rails, fuel comes out the Schrader valve when pushed in. Thanks in advance!
 
J

jdaj

Member
Aug 1, 2020
27
6
13
nj
Aug 21, 2020
#2
  • Aug 21, 2020
  • #2
could be many things going on. wiring or relay issues. ignition or fuel pump issues. time to start eliminating possibilities
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
27,827
10,508
203
polk county florida
Aug 21, 2020
#3
  • Aug 21, 2020
  • #3
#1 get a real fix on the fuel pressure with a gauge. You can rent or borrow one from autozone or similar parts store.
#2 get the battery tested, preferably after charging it, this is based on your description from attempting to start. Two separate problems.
Also this:

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

Cranks OK, but No Start Checklist for Fuel Injected 5.0 Mustangs model years 1986-1995 A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work...
www.stangnet.com
 

Dan02gt

mazing how much gas smell came from that tiny hole
20+ Year Stangneter
Mar 2, 2003
909
415
113
Greenville, NC
Aug 22, 2020
#4
  • Aug 22, 2020
  • #4
That’s a sign of failing caps in the computer. Might want to pull it apart and check them.
 
B

BuckleSwab

New Member
Aug 21, 2020
4
0
1
Georgia
Aug 22, 2020
#5
  • Aug 22, 2020
  • #5
General karthief said:
#1 get a real fix on the fuel pressure with a gauge. You can rent or borrow one from autozone or similar parts store.
#2 get the battery tested, preferably after charging it, this is based on your description from attempting to start. Two separate problems.
Also this:

Cranks OK, but No Start Checklist for Fuel Injected Mustangs

Cranks OK, but No Start Checklist for Fuel Injected 5.0 Mustangs model years 1986-1995 A word about this checklist before you start: it is arranged in a specific order to put the most likely failure items first. That will save you time, energy and money. Start at the top of the list and work...
www.stangnet.com
Click to expand...
Thanks, have to wait for fuel pressure tester unfortunately but there is a new pressure regulator in there.
 
B

BuckleSwab

New Member
Aug 21, 2020
4
0
1
Georgia
Aug 22, 2020
#6
  • Aug 22, 2020
  • #6
Dan02gt said:
That’s a sign of failing caps in the computer. Might want to pull it apart and check them.
Click to expand...
Appreciate the tip, pulled the computer and one of the capacitors is no good but the other two are good.
 
B

BuckleSwab

New Member
Aug 21, 2020
4
0
1
Georgia
Aug 23, 2020
#7
  • Aug 23, 2020
  • #7
So it seems like it was the computer, I put a new capistor on it today and she primes and engages faster then ever less then two seconds. I appreciate the help!
 
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
173
SN95 4.6L Mustang Tech Apr 27, 2026
n0v8or
N
Fuel Fuel Pump not Priming
  • Mcmahst
  • Nov 15, 2024
  • Fox 5.0 Mustang Tech
Replies
11
Views
557
Fox 5.0 Mustang Tech Nov 17, 2024
AeroCoupe
1999 Mustang GT - No Start- Need help understanding the fuel pump circuit and how it works
  • 99gtGuy
  • Nov 4, 2025
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
1
Views
469
1996 - 2004 SN95 Mustang -General/Talk- Nov 7, 2025
04newedge-
0
D
89 foxbody fuel pump not priming
  • Dubsantana
  • Jul 6, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
5
Views
455
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 12, 2025
AeroCoupe
B
'03 GT Fuel Pump/Pressure/Delivery Issue
  • Brodach
  • Oct 21, 2025
  • SN95 4.6L Mustang Tech
Replies
8
Views
813
SN95 4.6L Mustang Tech Oct 31, 2025
gkomo
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?