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

Fuel Pump problems

  • Thread starter Thread starter Gixxer750
  • Start date Start date Aug 9, 2004

Gixxer750

Founding Member
Feb 3, 2002
789
0
17
Saint John NB, Canada
Aug 9, 2004
#1
  • Aug 9, 2004
  • #1
Ok I am one of those guys that always turns the key and waits for the fuel pump to prime before I start my car. Last few days the pump primes but not as loud as it normally is. If I turn the key off and back on, it eventually gets as loud as it normally is. usually 3 key turns to get it sounding the way it always did. If I try to start off a weak prime, it takes a lot longer cranking over. Does this mean my fuel pum is on the way out??


Thanks
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Aug 9, 2004
#2
  • Aug 9, 2004
  • #2
stick a FP gauge on it and see what is goin on. you could also have regulator or check valve issues. good luck.
 
D

dromeda

New Member
Apr 17, 2004
146
0
0
Aug 9, 2004
#3
  • Aug 9, 2004
  • #3
Check the voltage after the inertia switch also. My friend's was really quiet. Found that it was only getting 6.5 volts (also explains his low fuel pressure problems).

Also as the pump fills with fuel it tends to quiet. 'Course you're seeing the exact opposite...
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Aug 9, 2004
#4
  • Aug 9, 2004
  • #4
the inertia switch is in series on the wire that goes to the FP relay, acting only as a relay coil. it either has enough juice to energize the relay or does not.
the wire from the solenoid (with fusible link) to the relay, and the exiting to the pump, is the wire that carries all the load to power the pump.
 

Gixxer750

Founding Member
Feb 3, 2002
789
0
17
Saint John NB, Canada
Aug 9, 2004
#5
  • Aug 9, 2004
  • #5
HISSIN50 said:
the inertia switch is in series on the wire that goes to the FP relay, acting only as a relay coil. it either has enough juice to energize the relay or does not.
the wire from the solenoid (with fusible link) to the relay, and the exiting to the pump, is the wire that carries all the load to power the pump.
Click to expand...


So this switch is under the drivers seat with the relay? or is it on the pump itself??

thanks
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Aug 9, 2004
#6
  • Aug 9, 2004
  • #6
Gixxer750 said:
So this switch is under the drivers seat with the relay? or is it on the pump itself??

thanks
Click to expand...
the inertia switch is in the trunk - near a light assembly's plastic shrouding. it should have a plastic pop off cover on it (ive never found mine, and it is probably different, since it is a vert). many have posted where it is before, in case you feel like searching.

good luck.
 

88hatchblack

New Member
Jul 25, 2004
163
0
0
Willard, Ohio
Aug 9, 2004
#7
  • Aug 9, 2004
  • #7
the inertia switch is in the trunk or hatch on the driver's side. there should be a gromet on the plastic panel that you will need to take out. the panel is on the very back on the drivers side next to the trunk latch. the interia switch is kind of a black rectangle with a small white button switch on top. check the voltages of the red/black wires there.
 
You must log in or register to reply here.

Similar threads

Engine Fuel not pumping
  • Creomod
  • Apr 13, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
51
Views
1K
Fox 5.0 Mustang Tech Jul 22, 2026
Noobz347
B
Electrical Why does my fox body keep frying eecs
  • brandyn200
  • Jun 20, 2026
  • Fox 5.0 Mustang Tech
Replies
8
Views
313
Fox 5.0 Mustang Tech Jun 25, 2026
AeroCoupe
S
FUEL PUMP ALWAYS ON
  • Scwhitten
  • Jun 6, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • 2
Replies
27
Views
556
1996 - 2004 SN95 Mustang -General/Talk- Jul 4, 2026
manicmechanic007
F
2004 Mustang GT – Fuel Pump Not Priming
  • Fayio
  • Apr 22, 2026
  • SN95 4.6L Mustang Tech
Replies
7
Views
364
SN95 4.6L Mustang Tech Apr 27, 2026
n0v8or
N
A
1987 5.0 speed density Foxbody crank no start
  • Alan2204
  • May 23, 2026
  • Fox 5.0 Mustang Tech
Replies
10
Views
349
Fox 5.0 Mustang Tech May 30, 2026
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?