No 02 Sensor Harness

[1987tystang]

87 mustang 5.0 flooding out and fouling plugs in minutes.

Passenger side is pointless long story... When u slide a motor back tight... So is everything else.

I'm focused on drivers side 02.
The plastic plug is melted (was never plugged in since I had the car) put a fresh motor in now I'm having flooding issues. Even so much I can't run very long with out draining the oil.

I traced the wires going to eec by the brake booster as shown in the picture.

What I want to try and do is splice into the harness here essentially making a 02 harness with out cutting off the plugs

Where to cut is one question
The green and yellow is to the fuse able link

Black, light green stripe to the #40 prong in eec

Dark green and purple is to the black wire on sensor (ground) going to #29 prong on eec but on the male end of plug the wire is light green

Does this sound correct as it can be?

 

[1987tystang]

Pix

 

[jrichker]

Why not just make a junkyard run and get the correct harness that matches the transmission type?

] O2 Sensor harness interchange and modification

Originally Posted by 302EFI [/b]

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 http://forums.corral.net/forums/gen...manual-auto-differences-year-differences.html 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 will cause no crank problems.
See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 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.

So far you got lots of advice, and most of it is incorrect. Put 12 volts on the wrong sensor lead and you will ruin the sensor.

The green/yellow wire is the 12 volts for the O2 sensor heater, the black/gray wire is the signal & heater power ground, other wire is the O2 sensor output. The sensor wiring is Teflon insulated to survive the high heat around the exhaust system. Use regular insulated wire on the O2 sensors and the heat from the exhaust will melt or damage the wire's insulation.

The numbers on the sensor body match the numbers on the sensor socket. That shows you what wires are the heater, ground and sensor outputs.

60 is the sensor and heater ground. It terminates up in the engine fuel injector harness with an orange wire that bolts to either the back of the cylinder head, intake manifold or car body. Make sure this is grounded if you want the O2 sensors to work correctly.

90 (dark brown/lt green)& 94 (dark green/Purple) are the O2 sensor outputs.

687 is the 12 volt O2 sensor heater power that connects to a fuse link in the wiring harness.

The diagram for the O2 sensor harness is below:
Diagram courtesy of Tmoss & Stang&2birds

nsor wiring is the same for 87-93 5.0 Mustangs [/b]

the computer wiring connector:[/b]

87-90 5.0 Mustangs O2 sensor wiring:
Computer pin 43 Dark blue/Lt green – LH O2 sensor
Computer pin 29 Dark Green/Pink – RH O2 sensor
The computer pins are 29 (L\RH O2 with a dark green/pink wire) and 43 (LH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.




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

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

 

[1987tystang]

Money being one issue, two taking the dash apart to swap a harness I'd prob rather just convert to carborated.

I asked a similar question yesterday but I'm not seeing any plug with a loop in it, not under the dash, engine bay, by tranny there's nothing. Who ever did this deserves a solid kick in the balls and probably a few more are deserved.

I'm no tech, or electrition just know enough to be dangerous at both.

From what I understand the main power to o2 is coming from the fuse able link (green/yellow stripe)

Two white wires on o2and one black.

So one question is: is the power going into the sensor regulated down to the Less than a bolt or does that happen at the sensor and it only puts out .04-.06 volt?

The black wire I'm assuming is going to the dark green/purple as a ground

 

[1987tystang]

I looked at few junk yards but I moved from pa to nc and they don't really have much

 

[1987tystang]

Green yellow strip

One coming from across firewall into fuse link the other end is going to the crimp, from the crimp one goes to the grey plug into the cab, the bottom right is going to the msd 6al ignition box

Where should the cut be?
Single wire coming across fire wall into the link?

 

[1987tystang]

Pix