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Electrical 91 GT foxbody fuel pump keeps priming

  • Thread starter Thread starter Frank cortez
  • Start date Start date Aug 20, 2021
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Frank cortez

New Member
Aug 4, 2021
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El Centro California
Aug 20, 2021
#1
  • Aug 20, 2021
  • #1
Hello so i fixed my ecm by putting in new capacitors but seems like that didn't fix it from priming all the time what could the problem be since i think two of the capacitors melted because of a short so what could be the problem
 

HemiRick

I'd be looking at jacking under the house
Jun 28, 2020
723
272
73
Memphis TN
Aug 20, 2021
#2
  • Aug 20, 2021
  • #2
The ECU is still not working, double check your work.
 
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Frank cortez

New Member
Aug 4, 2021
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El Centro California
Aug 20, 2021
#3
  • Aug 20, 2021
  • #3
HemiRick said:
The ECU is still not working, double check your work.
Click to expand...
Ive double checked many times and still nothing i removed the old capacitor wires and yes one line did get shorted because i tried to make a connection with a wire and that caused the fuel pump to turn off when i tried to crank it but i fixed that and still keeps priming
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,932
224
Massachusetts
Aug 20, 2021
#4
  • Aug 20, 2021
  • #4
Check continuity from pin 40/60 to pin 46. You should have it
 
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Frank cortez

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#5
  • Aug 20, 2021
  • #5
Mustang5L5 said:
Check continuity from pin 40/60 to pin 46. You should have it
Click to expand...
Could you show me a diagram or something to know where those pins are at
 
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Frank cortez

New Member
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Aug 20, 2021
#6
  • Aug 20, 2021
  • #6
Mustang5L5 said:
Check continuity from pin 40/60 to pin 46. You should have it
Click to expand...
Also how do i check which tool do i need and i just checked to see if im getting fuel to rails and yes
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,932
224
Massachusetts
Aug 20, 2021
#7
  • Aug 20, 2021
  • #7
You’ll need a multimeter. You can use resistance (ohms) to check if the multimeter doesn’t have a continuity function.

if it’s open, you have a burned pin 46 trace

the ECU pin connector is labeled. Look on the side of the plastic connector and you’ll see 1, 10, etc indicating which pin is what
 
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Frank cortez

New Member
Aug 4, 2021
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Aug 20, 2021
#8
  • Aug 20, 2021
  • #8
Mustang5L5 said:
You’ll need a multimeter. You can use resistance (ohms) to check if the multimeter doesn’t have a continuity function.

if it’s open, you have a burned pin 46 trace

the ECU pin connector is labeled. Look on the side of the plastic connector and you’ll see 1, 10, etc indicating which pin is what
Click to expand...
Ill have to go buy a multimeter
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,932
224
Massachusetts
Aug 20, 2021
#9
  • Aug 20, 2021
  • #9
Frank cortez said:
Ill have to go buy a multimeter
Click to expand...

this simple one will do your basic electrical and continuity testing that you’d use on a vehicle.

Etekcity Digital Multimeter, Voltage Tester Volt Ohm Amp Meter with Continuity, Diode and Resistance Test, Dual Fused for Anti-Burn, Red, MSR-R500 Amazon product ASIN B01N9QW620View: https://www.amazon.com/dp/B01N9QW620/ref=cm_sw_r_cp_api_glt_fabc_M231MWZZHVGQVEQQG5D6?psc=1
 
Reactions: General karthief
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Frank cortez

New Member
Aug 4, 2021
22
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Aug 20, 2021
#10
  • Aug 20, 2021
  • #10
Mustang5L5 said:
this simple one will do your basic electrical and continuity testing that you’d use on a vehicle.

Etekcity Digital Multimeter, Voltage Tester Volt Ohm Amp Meter with Continuity, Diode and Resistance Test, Dual Fused for Anti-Burn, Red, MSR-R500 Amazon product ASIN B01N9QW620View: https://www.amazon.com/dp/B01N9QW620/ref=cm_sw_r_cp_api_glt_fabc_M231MWZZHVGQVEQQG5D6?psc=1
Click to expand...
Okay so i bought one and where does the black cable go and where does the red one go in the ecu pins?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,932
224
Massachusetts
Aug 20, 2021
#11
  • Aug 20, 2021
  • #11
When testing for continuity, it does not matter what color probe goes where. You are simply completing a loop.

set the meter to the position that makes an audible tone. If you touch the lead ends the meter will make a sound. Now touch one probe to 40 and the other to 46. You should hear it ring.

if the meter doesn’t have sound, set it to resistance (ohms) and touch the two probes. If there is a connection the display will show numbers that eventually go to 0 indicating a solid connection.
 
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Frank cortez

New Member
Aug 4, 2021
22
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1
El Centro California
Aug 20, 2021
#12
  • Aug 20, 2021
  • #12
Mustang5L5 said:
When testing for continuity, it does not matter what color probe goes where. You are simply completing a loop.

set the meter to the position that makes an audible tone. If you touch the lead ends the meter will make a sound. Now touch one probe to 40 and the other to 46. You should hear it ring.

if the meter doesn’t have sound, set it to resistance (ohms) and touch the two probes. If there is a connection the display will show numbers that eventually go to 0 indicating a solid connection.
Click to expand...
Okay so if it has a solid connection then what because your saying that if pin 46 stays open the. Its bad
 
F

Frank cortez

New Member
Aug 4, 2021
22
0
1
El Centro California
Aug 20, 2021
#13
  • Aug 20, 2021
  • #13
Mustang5L5 said:
When testing for continuity, it does not matter what color probe goes where. You are simply completing a loop.

set the meter to the position that makes an audible tone. If you touch the lead ends the meter will make a sound. Now touch one probe to 40 and the other to 46. You should hear it ring.

if the meter doesn’t have sound, set it to resistance (ohms) and touch the two probes. If there is a connection the display will show numbers that eventually go to 0 indicating a solid connection.
Click to expand...
Okay so yes i tested and yes it went up and then to 0
 

JD1964

there is enough sticking out to grab on to
15 Year Member
Jun 28, 2013
3,432
1,524
194
Maryland
Aug 20, 2021
#14
  • Aug 20, 2021
  • #14
I failed at trying to fix the capacitors on my ECU. I ended up going with this service. Quick turn around and the replacement has been working perfect.

A9L A9P C3W A3M X3Z MUSTANG ECU PCM COMPUTER REPAIR SERVICE 5.0 REPAIR & RETURN | eBay

Mustang ECU Repair Service. Quick turn around after the computer is received. Easy repair process. If we are unable to repair your computer, WE CAN HELP! 701 La Veta Dr. Crank, no start?.
www.ebay.com
 
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Frank cortez

New Member
Aug 4, 2021
22
0
1
El Centro California
Aug 20, 2021
#15
  • Aug 20, 2021
  • #15
John Dirks Jr said:
I failed at trying to fix the capacitors on my ECU. I ended up going with this service. Quick turn around and the replacement has been working perfect.

A9L A9P C3W A3M X3Z MUSTANG ECU PCM COMPUTER REPAIR SERVICE 5.0 REPAIR & RETURN | eBay

Mustang ECU Repair Service. Quick turn around after the computer is received. Easy repair process. If we are unable to repair your computer, WE CAN HELP! 701 La Veta Dr. Crank, no start?.
www.ebay.com
Click to expand...
Ive never really sent stuff through mail
 

HemiRick

I'd be looking at jacking under the house
Jun 28, 2020
723
272
73
Memphis TN
Aug 20, 2021
#16
  • Aug 20, 2021
  • #16
You dont have a multimeter? How can you check your work?....use it to make sure the new caps make continuity to the circuits.
 
F

Frank cortez

New Member
Aug 4, 2021
22
0
1
El Centro California
Aug 20, 2021
#17
  • Aug 20, 2021
  • #17
HemiRick said:
You dont have a multimeter? How can you check your work?....use it to make sure the new caps make continuity to the circuits.
Click to expand...
Yes i bought one and yes i did put them okay but seems like pin 46 is the one that burnt but im checking and i soder the little connections from the back because i did see that the trace was brunt but seems like i didn't soder the piece of wire right
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,932
224
Massachusetts
Aug 20, 2021
#18
  • Aug 20, 2021
  • #18
Frank cortez said:
Okay so yes i tested and yes it went up and then to 0
Click to expand...

try pin 60 to 46 as well.
 
F

Frank cortez

New Member
Aug 4, 2021
22
0
1
El Centro California
Aug 20, 2021
#19
  • Aug 20, 2021
  • #19
Mustang5L5 said:
try pin 60 to 46 as well.
Click to expand...
Yes it also does the same thing
 
F

Frank cortez

New Member
Aug 4, 2021
22
0
1
El Centro California
Aug 20, 2021
#20
  • Aug 20, 2021
  • #20
Mustang5L5 said:
try pin 60 to 46 as well.
Click to expand...
Okay so ive been testing the ecm pins is that what i was supposed to be checking or was it where the the pins go?
 
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