Wrong o2 sensors for my computer?

[86gtriceeater]

Im putting my stock computer & engine harness back in my 86 gt after it sitting for over a year. Just before I blew the motor I had replaced the o2 sensors but more recently remember reading something somewhere about having to have different o2 sensors for maf vs speed density. That if you run incorrect o2 sensors you fry part of the computer. Can anyone enlighten me as to which o2 sensors to use? Im using stock engine harness 86gt 5.0 and stock speed density computer w offroad bbk h-pipe

 

[jrichker]

The O2 sensors are the same for Speed Density and Mass Air. The 4 cylinder and V8 sensors are different: the 4 cylinders are 4 wire and won't work correctly with a V8. The V8 sensors are 3 wire.

The wrong O2 Sensor harness can damage things.
Originally Posted by 302EFI
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

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 auto trans O2 harness with an A9P
Only run a 5 speed trans O2 harness with an A9L
90 model year harness only works with 90 model cars without inspection/rework.
The 4 cylinder O2 harness uses 4 wire O2 sensors. It probably won’t work correctly without modifying it.

 

[86gtriceeater]

Very helpful, thank you sir!