Electrical Issues with 91 mustang with a 93 5.0 motor

Theekinghumpy

New Member
Jul 3, 2019
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So I am new to the mustang world and I got a 91 mustang gt manual off a friend with no motor or transmission. Then another friend sold me his 93 motor and manual transmission. We dropped the motor in with no issues but I sent it to my local mechanic and he said he is having issue matching a engine harness. Is this a compatibility issue or does my mechanic not know what he's doing?
 
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Theekinghumpy

New Member
Jul 3, 2019
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Indiana
No harness yet. Mechanic said 91 and 93 diagrams are not matching. Honestly my buddy said I can take the harness out of the car we pulled the motor from. Will a 93 match my 91?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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No. I think the wire colors changed, you may be able to re-pin them but honestly get the harness that matches the car.
you are only needing the injector harness?
 

Theekinghumpy

New Member
Jul 3, 2019
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Indiana
The existing harness coming from the drivers side fire wall has multiple wires cut and I will buy a new harness I just don't know what to get with a 91 mustang gt hatchback with a 93 motor
 

Mustang5L5

This is a big reason why I pulled it out
Mod Dude
Feb 18, 2001
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Harnesses did change a few times between 87-93.

Best to stick with year of the body. Engine doesn't matter. An 87 engine will run in a 93 and vice versa. All that matters is the wiring for the year of the car, the ECU and manual or auto
 

jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
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The engine mounted fuel injection harness has the same wiring on all years between 87 and 93. Some of the wires different colors but the connector pinout is identical for 87-93 engines.

See the graphic for the 10 pin connector circuit layout.
68512.jpg


Computer wiring harness connector, wire side
71316.gif


Computer wiring harness connector, computer side
88243.gif



The following are diagrams courtesy of Tmoss & Stang&2birds

Complete computer, actuator & sensor wiring diagram for 88-90 Mass Air Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif



5.0 wiring diagram for Fuel Injectors, Sensors, and Actuators
fuel-alt-links-ign-ac.gif


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.


TFI module wiring for 94-95 Mustang GT
http://www.veryuseful.com/mustang/tech/engine/images/Mustang-94-95-IgnitionControlModule.gif

Complete computer, actuator & sensor wiring diagram for 94-95 Mustangs

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs

Complete computer, actuator & sensor wiring diagram for 88-90 Mass Air Mustangs

5.0 wiring diagram for Fuel Injectors, Sensors, and Actuators

Ignition switch wiring

O2 sensor wiring harness

Vacuum diagram 89-93 Mustangs

HVAC vacuum diagram

TFI module differences & pin out

Fuse box layout

Mustang 5.0 Lights and Radio schematic, by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxLights-Radio_diag.gif

87-92 power window wiring

93 power window wiring

T5 Cutaway showing T5 internal parts

Visual comparison of the Ford Fuel Injectors, picture by TMoss:

Convertible top motor wiring http://www.veryuseful.com/mustang/tech/engine/images/mustang88VertTopMotorCkt.gif

Engine mounted fuel injector harness

Location of the TPS, IAB, and the 10-pin connectors on a 5.0, picture by TMoss:

Starter circuit

Alternator diagram for 94-95 Mustangs.