SO ive done some research and found that the only way to do a plug and play install is to go chassis to chassis. My issue is that that i already have a 5.0 car but the harness has been cut into and patched a few times and i just dont like it. I looked into the summitracing efi harness and know that it wont work as plug and play, but what if i was willing to do some wiring. I know that 90s mustangs use a dual plug for the dash harness because of air bag hook ups and such. But in my cas i really dont care about airbags or egr or just about anything extra in the car. I know that summit kit is a bare bones kit that makes the engine run and thats about it. And all i use my dash for now is a speedo and tach, everything else is on different gauges. So could i delete the dash harness and the under hood harness. And just wire the connections that the summit harness needs in and run aftermarket gauges and have everything run correctly. Mainly what all is in the under dash harness that connects to the engine harness
Info on engine wiring harness install
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Its a 90 Lx and both the efi and main harness have been messed with. From looking at the ford racing harness diagram. the main harness has the the a/c and egr stuff on it. And since i dont have either of those things on the car anymore i dont think i need the harness anymore. And the headlights and horn are on another harness so those wont be affected.
When you say EFI harness are you talking about the engine mounted harness that connects to the fuel injectors, or the main computer harness that has the mass air sensor?
Find a harness from an 89 or a 90 5.0 Mustang and you will be good. Using an 89 computer harness will require some rework. The instrument panel connectors may need some minor modification to match the circuits, but it should not be a killer problem if you can read circuit diagrams.
Make a visit to the links I am posting and you will find a great deal of very helpful diagrams and information.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Wiring & Engine Info 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
Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_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
Find a harness from an 89 or a 90 5.0 Mustang and you will be good. Using an 89 computer harness will require some rework. The instrument panel connectors may need some minor modification to match the circuits, but it should not be a killer problem if you can read circuit diagrams.
Make a visit to the links I am posting and you will find a great deal of very helpful diagrams and information.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Wiring & Engine Info 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
Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_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
looking at these install instructions, this is how a new wiring harness should be ran.
http://static.summitracing.com/global/images/instructions/fms-m12071f302.pdf
Looking at how much is in the original main and engine harness, and how much less is in the summit harness. i also looked into the florida 5.0 gauges and they would fix my cluster issue and also put me a pigtail for a check engine light which i can wire to the line supplied in the summit harness. The summit harness just moves all the power distribution and all motor control to the passenger kickpanel effectively. And since i dont have a/c or egr the circuit are cut out of the harness to begin with so its a much cleaner look as well. The headlights are on a different harness. And the ignition switch could be easily pin'd out. Also since i would delete cruise control and air bags as well all of those harnesses under the steering column would be removed and the horn, turn signal, and igntion would be left. Thats all that is really on the under dash harness, since the ignition switch powers the fuse box which powers the car. Worst case senario i could always just remove the equipment and keep the underdash harness as entact as possible and just clean up the engine bay.
http://static.summitracing.com/global/images/instructions/fms-m12071f302.pdf
Looking at how much is in the original main and engine harness, and how much less is in the summit harness. i also looked into the florida 5.0 gauges and they would fix my cluster issue and also put me a pigtail for a check engine light which i can wire to the line supplied in the summit harness. The summit harness just moves all the power distribution and all motor control to the passenger kickpanel effectively. And since i dont have a/c or egr the circuit are cut out of the harness to begin with so its a much cleaner look as well. The headlights are on a different harness. And the ignition switch could be easily pin'd out. Also since i would delete cruise control and air bags as well all of those harnesses under the steering column would be removed and the horn, turn signal, and igntion would be left. Thats all that is really on the under dash harness, since the ignition switch powers the fuse box which powers the car. Worst case senario i could always just remove the equipment and keep the underdash harness as entact as possible and just clean up the engine bay.
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