Dude, if you are going to fix the problem, you will have to get out your DVM or Multimeter and do some checks. Computers don't die for no reason, you have some wiring gone wrong or an incorrect O2 sensor harness. I have laid out the basic plan to get you started in my previous posts.
ok my harness is out of an 88gt speed density with 5speed. tapped pins for mass air and ran a9l eec and couldnt pull codes and never could get it tuned consistantly. done some reasearch. have 24lb inj. and mass air calibrated for them alum heads.e cam . my question is is it right cpu do i need a9p or 93 cobra to compensate fuel map. from what i gathered a9l may burn up due to some o2 wiring in 88 harness
The red/blue wire feeds power the starter solenoid and the TFI module. It is energized when the key is in the Start position to crank the car and tell the TFI to provide more dwell for increased spark for cranking.
The pin 46 is signal ground for all the engine mounted sensors and the MAP/Baro sensor. It is always grounded no matter what position the ignition switch is in.
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
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.
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.
If it is a 5 speed O2 sensor harness, it is usable without any modifications when you do a mass air conversion and use an A9L computer and 5 speed transmission.
Is pin 30 grounded only on diagnostics or can I keep it grounded. Had this thing wired for 2 years had 1 problem pulled harness out and want to make sure its all right. Yall guys have been helpful and appreciate it just want it right. Wiring schematics are nice but if I could get which pin to power start and run, and start , and what needs to be grounded. Thanks
got it going again found a few hiccups in wires. pulled a few codes 95, 31, 22, 84, 87, 85, 81, 67 all emissions stuff removed because of swap so half of them i can ignore. everything for egr was removed left it plugged in though,.