Although the 1987 speed density Mustang did not have the looped wire on the O2 harness connector, did they have a different O2 harness between the 5 speed and AOD trans like the Mass Air cars had???
I wonder about the year 1987 included in this as shown? As you can see by my pics. My 87 has no looped wire on the O2 harness connector nor is it even pinned for one. Was my 87 part of some built without this? Or were all 1897 5.0 models built like this?Here's what I have for Mass Air cars. Maybe someone else will chip in with some information specific to the 87 Mustang.
Diagrams courtesy of Tmoss & Stang&2birds
O2 Sensor wiring harness. Check the part numbers on the drawing against the 87 O2 sensor harness and see if they are the same. If so, the O2 Sensor harness interchange and modification tech note below applies.
O2 Sensor harness interchange and modification
Originally Posted by 302EFI
Revised 16-Oct-2011 to add O2 sensor harness warnings
The wires for the 02's and low oil did not change throughout the years, they are all in the same place.
The main ones you need to worry about are (on the harness end (ECU) that plugs into the 02 plug) is:
\- 1. Lightblue / yellow
- 2. White / Purple
- 3. Purple / Yellow
The White/Purple & Purple/Yellow gets looped for a automatic ECU
The Purple/Yellow & Lightblue/Yellow for a manual ECU
Not all wires are shown for clarity and simplicity
See Oxygen sensor Harnesses - Manual/Auto differences and year differences - Ford Mustang Forums : Corral.net Mustang Forum for more O2 sensor wiring harness info
Basic premise to use with transmission swaps:
Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans may cause no crank problems.
See Computer issue? | Mustang Forums at StangNet for Joel5.0’s fix to the computer internal signal ground.
The 4 cylinder O2 harness uses 4 wire O2 sensors. It probably won’t work correctly without modifying it.
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.
94-95 Mustang wiring diagrams
Mustang FAQ - Wiring & Engine Info
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
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
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
O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.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 & pin out
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
87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif
93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif
T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg
Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg
Since you seem to have some knowledge and interest in this, hopefully you have some input. By looking at the picture, it appears that the OP's O2 harness is not looped.There is no difference on the non mass air cars.
I also wonder if Joe would know what I would need to do to make my speed density O2 harness compatible to the A9L. What I have seems to function but I would all the proper set up for a mass air, M.T. car ie: matching trans, ECU and O2 harness.I wonder about the year 1987 included in this as shown? As you can see by my pics. My 87 has no looped wire on the O2 harness connector nor is it even pinned for one. Was my 87 part of some built without this? Or were all 1897 5.0 models built like this?
Since you seem to have some knowledge and interest in this, hopefully you have some input. By looking at the picture, it appears that the OP's O2 harness is not looped.
It is possible that someone modified the original O2 sensor wiring by placing the loop at a different place in the wiring. Or we are looking at the body mating section of the harness opposite were it is looped. What's your call on this?
No its not modified. That's how the Speed Density 02 harness is supposed to be. On the mass air cars, Ford didn't run the additional circuits through the 02 harness like they did on the mass air cars. The Speed Density wiring completely bypass's the 02 wiring and goes straight to the ECM. So both manual and auto SD cars use the same wiring layout. That's why there is no loop in the 02 harness.