LA3 Swap into an SVO

(should also work for a turbo GT or early Turbo Coupe)

Well the LA3 is the last of the 2.3 turbo computers produced by Ford.  For this reason, it offers certain advantages.  I found out from others, that the LA series computers run at 12 mhz, and the previous 2.3 turbo computers run a 7.5 mhz.  As a result 2.3 turbos with LA computers idle smoother, throttle response is quicker and driveability improves.  There are less hesitations, stumbles and other computer related riff raff.  The LA, LA2, and LA3 are all very similar.  Some say one is no better than the other, but some insist the LA3 is the best.  The LA series of computers come in the '87 and '88 turbo coupes.  The computers do have some distinct wiring differences compared to their other turbo 2.3 EEC IV brothers.  To see these differences in a nice chart format please go to GT350Rs website.  You will notice some of the wiring is different, and the LA computers have a lot more wires in general.  There are 6 specifically that need to be changed and or added to work in an early 2.3 turbo car.  The LA computers will allow earlier turbo cars to use larger 35# injectors and an intercooler to gain a lot of power.  On early '85 SVOs like mine and all '84s you have to switch to 35# injectors as well.  You can even put an LA3 into a late '85.5 SVO or '86.  It won't make more power, but it should drive and idle better.  I took the chart from GT350Rs page and wrote a simple procedure to perform the swap.  I also made notes of the wire colors from factory wiring diagrams and I will share all of that here.  All SVOs should have the same color wiring; I'm not sure about turbo GTs and early turbo coupes, but they are probably the same as well.  Be sure to do the first step in the order I put it below, or you'll have more than one wire loose at a time.  You only want to move one wire at a time to prevent possible mistakes.  

To get you pumped here is a pic of my LA3 installed and not bolted back in.  I went for a test drive shortly after this and was wowwed to put it mildly!

Ok, first you have to remove the old computer.  Simply yank the passenger footwell outer kickpanel away.  You'll see the computer which has a plastic brace holding it in.  The brace is held in by one 7 mm sheet metal screw.  Once you have the computer free, you have to unbolt the wiring harness.  It's a 10 mm bolt.  Pull of the plastic cap as well.  Now you have a whole mess of wires.  If you look where the harness plugs into the computer you will see a red piece of plastic.  This piece lockes the wires into the big grey plug.  Remove the red piece by prying it out with a small thin screwdriver.  Don't worry none of the wires are gonna come out inadvertantly.  Look at the grey plug.  You'll see the pin numbers on the top and bottom rows.  You have pins 1-20 numbered and 41-60 numbered.  Pins 21-40 are not numbered, but you should be able to count them.  Pull wire #43 first and put it into pin slot #27.  This is a white wire with a black stripe.  (mine looked almost yellow)  It's for the Vane air temp.  Now put wire #25 into pin #43.  (That's why you should move #43 first!).  It is a light green wire with a purple stripe.  That's the Vane Air Flow sensor.  Now swap the purple wire in #32 to pin #31 for boost control.  Next swap the #35 yellow wire to pin #33 for EGR shutoff.  After that move the yellow with red stripe #30 wire to pin #24 for the octane switch to work.  Pretty easy huh?  Don't worry just yank on the wires and move 'em.  They come out and you won't hurt them.  Now you have to add a wire to #25 for the ACT (air charge temp) sensor.  You will have to put an ACT sensor in your intake tract between the intercooler and engine.  The '87/8 turbo coupes have a bung in the lower intake for one.  You can drill and tap yours or put it where ever else you like.  I swapped to an '88 turbo coupe lower intake with an '86 SVO upper.  Note if you are swapping to a new style intake on an older turbo GT, SVO or TC you will need to get a different fuel rail.  Try and get one off a Merkur with a square style intake.  Now that you have the wire added for the ACT, you have to put another wire in for the signal return for the ACT.  Well underhood you can find a black wire with a white stripe going to the throttle position sensor, water temp sensor, fuel injector harness or even the EEC tester port.  I just tabbed mine into the EEC test port for now.  I'll probably wire it into the singal return elsewhere soon.  I tabbed it in for quick testing.  I hope this helps those of you considering this swap.  In all reality it is very easy and I don't understand now why I was dreading it so much.  It is easy!  If you have any questions, drop me a line.  I'll help you or find someone that can.  Note you can also hook up #2 for brake on / off, and #34 to a vehicle speed sensor.  I 've heard that they aren't necessary, but I've also heard they improve the idle even more and mileage.  The car will run good without them too, I know.