Fox 1986 Mustang LX Convertible 3.8L fuel pump issue

jwrules

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Apr 29, 2024
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I have a 1986 Mustang LX Convertible with a 3.8L fuel injected motor that my fuel pump isn't working. Before I drop the gas tank and replace the fuel pump i want to do everything I can to make sure that is my issue. I replaced the Fuel Pump Relay being i didn't hear it energize when I turn the key on. With the new one installed I here it energize when I turn on the key (clicks) but I do not have 12 volts on the Pink/Black wire going to the fuel pump. When I turn the key on I have 12 volts on the Yellow wire (coming from fusible link) and I also have 12 volts on the Red/Black wire coming from the Inertia Switch. There is a Tan/Light Green wire going to the Fuel Pump Relay that has no power neither, no 12v. I have read that the ECC supplies the ground for the fuel pump so could that be my issue, grounding? Is there a way I can test it without taking out the ECC? I also see on my schematic that there is an ECC Power Relay. Does this have anything to do with the power going to the fuel pump? If so is there a way of testing it?

Thank you for all of your help.
 
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This is the wiring diagram for your '86 (I copied it from here: http://www.veryuseful.com/mustang/tech/engine/#Diagrams):

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You can see that the yellow wire should be hot at all times. The fusible link is on the starter solenoid on the inner fender. The red/black wire from the inertia switch comes from the EEC power relay which is hot when the key is in the run or crank position. The tan/lt green wire comes from the EEC and it is a ground signal as you indicated. The Pink/black wire is the 12V+ to the fuel pump.
 
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