When swapping in a HO motor and T5, do I have to change computers?? Plan on staying speed density if that makes a difference.
Yes, you need one from a speed density Mustang or Mark VII.
Auto, stick or doesn't matter?
I'm not sure if there is a difference with speed density, just mass air.
Here's some info from CoolCats.net
You must also get a compatible EEC-IV computer module to use with your motor. You will not be able to reuse your stock one. Each Ford EEC processor has a calibration code printed on top, usually 3 characters long. For speed density, a computer marked with DA1 or DB1 (1987-88 Mustang) will work. You could also use a 1988-92 Mark VII computer (DX3, DY3, VL2, D9S) although you will be speed limited to 105mph with most of them. For mass air, the ever-popular A9L (manual) or A9P (automatic) are the computers of choice; see this site for a list of other computers that may also work. Most of these computers are easily available on eBay if you can't find one at the salvage yard, but you can also get remanufactured computers at parts stores (though we hear the quality ishiznit-or-miss so buyer beware). Don't forget to also strip the firewall of all related sensors, wiring, and vacuum lines from the donor car.
I'm pretty sure you want a DA1 (speed density 5-speed) Mustang computer.
I'm in the process of the HO swap, putting a 92 Mustang 5.0 into my 88 XR-7. My mechanic thinks we can use the stock computer to check for any codes before installing the A9P ecu and mass air sensor and adapter. Can this be done in a two stage process like he wants? I've told him that my resources (you guys and CoolCats) say no..
It will work for what he wants to do. The issue is firing order being different between the two engines and computers. I suppose he could try to move Injector connectors and plug wires around to mimic the HO if he is wanting to fire it on the old ECU.
John
I thought it might be possible with the plug wires switched, but hadn't thought about the injectors. Thanks for the input.
If you are just doing a static check(non running), the firing order of plugs and injectors are meaningless..
When I converted my Turbo Coupe I connected the sensors and scanned computer with no engine or transmission in car... Gave codes fo fuel pump monitor(purposely disconnected) and transmission selector(mounted on transmission)... Inst eng & trans, it fired without issues...
Meh. Just swap the 92 engine in, connect everything like it is on the stock 5.0 in the car (except the MAP sensor), move the two Thermactor wires, and splice in the MAF harness.
If you don't have any codes now you won't get any from the swap. Unless you do some janky wiring adding the 4 wires for the MAF :mullet:.