Engine ECU Question

GeorgeE · 2026-10-12T07:48:35-0500

I'm the original owner of an 89 5.0 LX, 5 speed. It has low milage, but as I'd like to keep it for a while, thought it would be a good idea to accumulate some spare parts while they're still available. One of these spares would be an ECU. The original part number is E9ZF-12A650-A2A. Some vendors have these, but they're over $700. I've found another less expensive one with a part number of E9ZF-12A650-AA. Would anyone know if these are interchangeable? Thanks for any help.

keel · 2026-10-12T09:19:11-0500

ECUs are rebuildable/serviceable (to a certain extent). I sent my ECU to ECU Exchange to get freshened up for about $200. This is always an option for you rather than buying a spare.

Mcmahst · 2026-10-12T09:19:33-0500

If this isn’t your daily driver, you could always use the service company ECUExchange, located in Florida, to test and rebuild ypur original as needed. I’ve had mine tested and repaired by them. Good luck.

GeorgeE · 2026-10-12T13:57:29-0500

I'd definitely have my original rebuilt as you suggest if it fails. I was hoping to find a reasonably priced backup though as I've never had a lot of long term luck with these things. At least on Chevy's. Thanks for the responses.

Noobz347 · 2026-10-12T14:05:22-0500

Yours has lasted 37 years. It's not like they are particularly fragile.

If you're going to keep a spare of something, keep a spare clutch kit.

keel · 2026-10-12T15:44:15-0500

GeorgeE said:
I'd definitely have my original rebuilt as you suggest if it fails. I was hoping to find a reasonably priced backup though as I've never had a lot of long term luck with these things. At least on Chevy's. Thanks for the responses.

I can't really speak to how Chevy and Ford ECUs are different in their construction but if you poke around on this forum and other late model Ford forums you will find that Ford EEC-IV computers are very solid. Issues are uncommon and when they do pop up its almost always aging capacitors, which by this point is a well documented and repairable problem.

GeorgeE · 2026-10-12T16:31:11-0500

I have heard that Ford made good ECU's. I'm probably over thinking this.... Hope the clutch doesn't go as the car only has 20k miles. It's an occasional weekend toy.

rednotch · 2026-10-12T16:36:10-0500

Buy a spare off local facebook, don't pay eBay prices, three letter catch codes really don't matter to much vs matching auto to auto and 5spd to 5spd.. Rebuild it or send it out. Only one I would send one to is keyworks, too many others replace a few things and gives everyone the same canned response of we replaced so and so.

Most I'd pay for a core is $120 and at this point in age there all cores, never had a problem finding one. There dead simple single layer boards.

rednotch · 2026-10-12T16:42:10-0500

And both those part numbers E9zf AA and A2A are A9l's. so pretty much any foxbody 5spd mass air ecu will work.

keel · 2026-10-12T17:23:33-0500

GeorgeE said:
I have heard that Ford made good ECU's. I'm probably over thinking this.... Hope the clutch doesn't go as the car only has 20k miles. It's an occasional weekend toy.

Post some pics!

GeorgeE · 2026-10-12T18:13:02-0500

As you can see, I like red. I think I'll get the cheap AA and skip the A2A and hope for the best.

General karthief · 2026-10-12T19:22:11-0500

If all's good now, although I'd send it to get checked anyway, cheap tuneup so to speak, it likely won't tell you it's malfunctioning, you have to ask the computer, I'd look for a A9L on the facepage local, you can hold it in your hand.
700 bucks and ebay? Not me.

keel · 2026-10-12T20:51:19-0500

GeorgeE said:
As you can see, I like red. I think I'll get the cheap AA and skip the A2A and hope for the best.

Sucker is mint. Don't know if you've been watching the market on low mileage notchbacks but they're worth a good chunk of change these days.

Engine ECU Question

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I'd like to remain having one chocolate starfish

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wonder how much it would cost to ship you a pair

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