If you didn't get a code 67, there is no reason why you can't get accurate engine running codes. Code 67 prevents you from getting the engine running codes. Dump the codes and try again.
The O2 sensor harness is the same from 88-9.3 The qualifier is that Auto transmission O2 sensor harnesses are different from manual transmission harnesses.
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. There is a fuse link for the O2 sensor heater power. According to Ranchero50, it is in the wiring near the passenger side hood hinge. Measuring the voltages will give a clue if it has shorted to the O2 sensor signal lead. The O2 sensor voltage should switch between .2-.9 volt at idle.
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]
View attachment 555760
ication
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
View attachment 555761
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 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
http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.
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