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

1994 5.0 fuel pump circuit issue

  • Thread starter Thread starter RockOn
  • Start date Start date Mar 24, 2022
R

RockOn

Member
Feb 24, 2016
24
2
13
Mar 24, 2022
#1
  • Mar 24, 2022
  • #1
So I have an intermittent fuel pump no-prime or shut down if I move my ECC from a horizontal to a vertical position.

So a few items:
- I know it’s solid state and orientation does matter
- I hear a relay clicking button can’t tell if it’s just the PDC relay and not the fuel relay
- in the inoperable position I have swapped relays to test for a bad one
- I can move the ECC while the car is running and the pump will shut down and then come back on

Based on the wiring diagram and in the inoperable position, I think that;
- I can jump the test connector (Wht/Pink to LGT B)
- if I get power to the pump then there is a short between the test connector splice to the
- if no ground to the pump then the short has to be somewhere between the splice and the pin connector (I think it is a this)

Just wanted to run this logic by people.
doesn’t seem that the ignition relay, the +12, or the DK Green monitor items would be of issue.

Thanks
 

Bullitt347

I have been doing it wrong this whole time
15 Year Member
Mar 23, 2007
3,960
2,919
194
Middle of Maine
Mar 24, 2022
#2
  • Mar 24, 2022
  • #2
Sounds like a broken wire, or a wire with corrosion.
Another possibility is that the connector to the PCM has terminals that do not have a tight fit with the connector, so that when you move the PCM the harness is pulling on the terminal either making a better or worse connection.
 
R

RockOn

Member
Feb 24, 2016
24
2
13
Mar 24, 2022
#3
  • Mar 24, 2022
  • #3
Thank so will check the 22 pin on the harness side connector. It does it with 2 different ECCs as I first though it was a bad ECC.

And I’d be right that if it’s a wire it’s the Lt Blue some where pin to PDC fuel relay?
 
J

joes snake

Founding Member
May 26, 2001
154
0
16
Ruskin, FL
Mar 28, 2022
#4
  • Mar 28, 2022
  • #4
Fixed?
 

WhiteCobra95

10 Year Member
May 2, 2006
634
177
74
Mar 28, 2022
#5
  • Mar 28, 2022
  • #5
Are there any good sources for replacement ECU pins (harness side) or connectors?
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,901
10,555
203
polk county florida
Mar 28, 2022
#6
  • Mar 28, 2022
  • #6
This may help id what you need
https://www.motorcraft.com/content/dam/ford-motorcraft/en_us/motorcraft_global/products/wire_sets_wiring/18376-Pigtail-Book-2016.pdf?fbclid=IwAR2uO418H2VMD6TaFoEMgVPw-XLqq3TBFeYITwTU5MCElwH36jUt-XxDyvo
 

Blown88GT

Founding Member
Nov 13, 1999
2,283
524
164
Palm Beach Gardens, FL
Mar 28, 2022
#7
  • Mar 28, 2022
  • #7
WhiteCobra95 said:
Are there any good sources for replacement ECU pins (harness side) or connectors?
Click to expand...
Salvage yard, if you're lucky. Any Ford of the era will do.
 
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