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Electrical Help Please!! 92 Mustang GT!! Beware Electrical Issues Are At Hand!!

  • Thread starter Thread starter notrubskwah
  • Start date Start date Apr 6, 2019
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notrubskwah

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Apr 18, 2011
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Apr 6, 2019
#1
  • Apr 6, 2019
  • #1
Hello, I have a 92 mustang gt convertible i just bought, fuel pump was hot wired drove it home. Now I am trying to sort the reason for the fuel pump not to be working properly. I found that the wire from pin 22 is sending out 12v to the relay instead of ground signals. I did find a resister that is a bit smoky, looks like it tried to scorch the board, just a bit of heat. Anyways the problem is I wanted to try and replace the resistor and I can not make out the color bands on it to buy a proper replacement. I was wondering if any of you can take a pic of your board, a close up of the resistor. I have scoured online looking at photo after photo some have the same resistor as mine(tan) and some are blue, dont know if that matters. My stripes is what i cant make out, i think they are gold, gold, maybe a green or blue, and then lastly maybe a brown, in the pic i have already removed the resistor but it is placed where it is supposed to be on the board. Also the typical burnt trace on the other side had been jumped already and caps have been replaced already, thanks in advance for any info!!
 

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notrubskwah

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Apr 7, 2019
#2
  • Apr 7, 2019
  • #2
Anyone please!!
 

General karthief

wonder how much it would cost to ship you a pair
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#3
  • Apr 7, 2019
  • #3
I'll jump in here and say I would either buy another ecu or send that one off to be repaired. But then I'm not into that changing those little diodes so I leave that to someone that does it.
 
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notrubskwah

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Apr 7, 2019
#4
  • Apr 7, 2019
  • #4
Thanks, I've repaired many electronics, this isn't no major repair and I probably have what I need laying around here. The color bands are important I have to put one back that is really close in value.
 
Reactions: General karthief

Blown88GT

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Apr 7, 2019
#5
  • Apr 7, 2019
  • #5
The resistor you have there looks okay.
I can't see the marking on TMoss's pic. Maybe you can.
 
Last edited: Apr 7, 2019
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notrubskwah

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Apr 7, 2019
#6
  • Apr 7, 2019
  • #6
thanks for the reply that one is blue I don't know if it's the same, mines tan. This resistor about has to be bad, I know it's not black but it did leave a smoke stain on the board and the solder was blown out around one of the legs before I removed it, and it's visually dull in comparison to the others. I opened my 351w computer and it has one that looks very close in colors I may just use a resistor like it, which is 100 ohms 5%.
 

Blown88GT

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#7
  • Apr 7, 2019
  • #7
Let's analyze the circuit as any good Sparky can do.
If it's just grounding a relay coil, it may only be there for safety, in case the relay is not attached.
If that's the case, 100 ohms is good. Tolerance is not important.
 
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notrubskwah

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#8
  • Apr 7, 2019
  • #8
The top leg traces into the red thing ( sorry haven't dealt with those any) the bottom traces into the right leg of the mosfets I'm pointing to.
 

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Blown88GT

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#9
  • Apr 7, 2019
  • #9
It's a capacitor. Probably a film type.
The MOSFET is the driver.
Fuel pump relay ground shares return (pin-37) with fuel injectors, etc.
Caps will suppress inductive spike.

TMoss might have more details here.
http://www.veryuseful.com/mustang/tech/engine/#EEC
 
Last edited: Apr 7, 2019
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notrubskwah

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#10
  • Apr 7, 2019
  • #10
do you mean its a cap problem? they have been replaced already by someone and looks good visually, i can remove and test if need be but this resistor i pulled still needs replacing, and i just wanted to make sure i put the right value back. I put my windsor computer in the car and the fuel pump worked like it was supposed to and the car fired up, but obviously cant use a windsor map sensored computer with a mass air so it doesnt run long.
 
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notrubskwah

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#11
  • Apr 7, 2019
  • #11
i wish i knew what the mosfet controlled, computer seemed to control everything fine except the fuel pump wouldnt work at all with it. im hoping just replacing the resistor will get it back.
 
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notrubskwah

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#12
  • Apr 7, 2019
  • #12
and now i see what you mean about the red thing being a film capacitor.
 
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notrubskwah

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#13
  • Apr 7, 2019
  • #13
Can you tell the second color? I'm thinking it goes: brown,gray,brown then gold which is 180ohms I believe.
 

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notrubskwah

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#14
  • Apr 7, 2019
  • #14
Bottom
 

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Blown88GT

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#15
  • Apr 7, 2019
  • #15
notrubskwah said:
i wish i knew what the mosfet controlled, computer seemed to control everything fine except the fuel pump wouldnt work at all with it. im hoping just replacing the resistor will get it back.
Click to expand...
Google "eec-iv schematic".
Unfortunately, most are wiring diagrams for the I/O, not the EEC-IV circuit board.
You could trace the circuit & draw it up yourself.

Looks like it could be 180 ohms. You could ask Tim Moss, he probably knows. He's a member of all the Mustang forums.
https://www.stangnet.com/mustang-forums/members/tmoss.17697/
 
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