Okay so this may be a little long but want everyone to know the story behind the car so any answers I get will have the whole story. Its an 88 t-bird turbo coupe with a 5.0 swap. When the car was first swapped it was a 5 speed car and now has a built AOD in it. The issue is the car breaks up and boggs down to what seems to be fuel starvation only at wot. Up to 3/4 throttle car runs good and idles well. What I know is the car used to be supercharged running a Paxton unit. I believe that is why it ran fine before. The o2 sensors are disconnected forcing the computer to run in open loop and the boost would mechanically force fuel through the use of the FPR at wot but now there is no forced induction no added fuel pressure and therefore I think this is my issue. If my o2 sensors were connected it would run better in closed loop. Now the car still has an A9L computer and I have read about frying the computer issues due to the computer getting power through a port that is supposed to see ground from a neutral switch. What can I do to make my setup work? I am willing to make up a harness or whatever I just need to know if its doable and howbto hook it up? Power or ground or???? Any help would be appreciated.
I should also include the car has 24lb injectors, a 90mm mass air calibrated for the injectors, a fenderwell cool air intake, gt40 upper and lower, Mac flowpath headers, xpipe with flow masters and dumps. When I tried setting fuel pressure at a normal base 36, 38 or so it breaks up lower in the rpm range in order to run up to 3/4 throttle I am running 44 lbs fuel pressure at idle which makes it boggish down low. hElp
The problem is with the O2 sensor harness and how the start circuit is wired through the O2 sensor harness.
Here's what I know so far. 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
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 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.
OK so I bought and auto sensor harness on eBay and I am going to pick up a c3w auto EEC this weekend. The harness does not exist in the car currently. If I plug in the c3w it should run how it does right now correct? Then all I would have to do is install the o2 harness and tap in wherever I need to? How will I need to tie in the harness for the o2 sensors?
im getting conflicting info..that o2 sensor looped wire for the t5 looks to be for years 88-90 according to this website http://ponyperformance.com/ (go to technical and scroll all the way down to the o2 sensor harness identification). years 91-93 have a different looped wire (see diagram in attachment in the link)