84 mustang EFI conversion.....Help!

This will make life easy!

http://www.msefi.com/

Pins 37 & 57 receive power from the EEC (electronic engine control
or computer) relay. Be sure to use a relay so that the computer gets
full power and does not have any voltage drop due to resistance of
the ignition switch and wiring. See the top center part of the diagram
that follows.

Diagram courtesy of Tmoss & Stang&2birds


Power source for EEC relay coil and EEC main power.
On your car, use the same wire as the one that feeds the ignition coil
to provide power to the relay coil. The EEC relay gets the power
feed from the starter solenoid with a 20 amp inline fuse or fuse link.
Use 12 gauge wire for the power feed to the EEC relay and to pins 37
& 57 on the computer.

EEC ground
Do not neglect the computer power ground. It is the second most
important ground on the whole car. Use 12 gauge wire for pins 40 &
60 on the computer power ground.

The computer has its own dedicated power ground that
comes off the ground pigtail on the battery ground wire. Due to
it's proximity to the battery, it may become corroded by acid
fumes from the battery. It is a black cylinder about 2 1/2" long
by 1" diameter with a black/lt green wire. You'll find it up next to
the starter solenoid where the wire goes into the wiring harness
Picture courtesy timewarped1972


Mini starter solenoid wiring


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Automotive wiring is different from hose wiring. In an automotive circuit, the ground
is the return path for power to go back to the battery.

The black/green wire is the relay ground: it grounds to the body.

The red/lt green wire is the relay coil power. It supplies power to activate the relay so that
power flows from the black/orange wires to the computer.

Remember that the computer does not source any power to actuators, relays
or injectors, but provides the ground necessary to complete the circuit. That
means one side of the circuit will always be hot, and the other side will go to
ground or below 1 volt as the computer switches on that circuit.

The tan/lt green wire is the switched ground for the fuel pump relay. When it goes to ground,
the relay closes and powers the fuel pump.
The fuel pump can be tricked intorunning by grounding the tan/lt green wire.
It does not harm the computer if you ground the tan/lt green wire.