Recently my ecm turned to toast (1994 F150 2WD Auto 4.9L). I mean literally, something inside shorted out and melted part of the circuit board. Happened totally out of the blue while driving.
2 questions.
One, does anyone have some idea what could cause this? The only clue I have is my ignition (lock cylinder) has been getting looser over the years and recently I elected not to use the key (because it removes easily even when turned on, and also the key slots in the cylinder have gotten so they don't line up and it is difficult to line them up in order to put the key back in). So I have been turning the ignition to "off". If I turn beyond "off" (to "lock"), then I do have to put the key back in (after jiggling the chrome "handle" around to get the key slots lined up) to get the switch to rotate. Crap I hope somebody understands what I just wrote besides me.

Two, a salvage yard (after assuring me the part numbers matched up), sent me a EEC-IV that is a F3TF-ZA, and mine is an F3TF-ZB. Anyone know if those are interchangeable numbers, or did this salvage yard just screw me?

Thanks for taking time to try to help.

 

Welcome to the forum! I'm not sure if this could answer your first question, but my truck is doing the same key tricks. I don't think it's normal, but i'm used to it. I guess that something's wrong with lock mechanism. Previous owner of my truck told me that he "broke something" in it.
As far as i could find out from internet, both computers you've mentioned are designed for I6 4.9L engine.

 

my key ring on the columb spins the same. only with the key can you actually move it to either position. start,lock,acc. my ? is how much difficulty is it to repair this key ring to stop this obvious malfunction ?

 

Yeah, mine's not too bad yet but it makes that annoying ding, ding, ding all the time, whenever the door is open; like the key is in the ignition still. I though about replacing the whole ignition cylinder but I haven't priced it or anything. I've got to fix some other things first.

 

Well the lock cylinder is very easy to replace (on my year anyway), just place in "run", and push a small punch (1/8" or so) up through the bottom of the steering column shroud to depress a spring loaded button, and then it pulls right out. On mine there is a dedicated hole in the shroud for this, but some may have to remove the shroud first.
The lock cylinder and key is $16, or a different one for $30-something. Don't know what the difference is. Got mine at O'really?s.
A Ford parts guy told me that there is an electrical contact on the lock cylinder (for the buzzer and steering lock?) that could potentially cause a problem with the ecm... rumor only, but I replaced mine just in case.
Only downside really is now I have to deal with 2 separate keys, unless I want to bother with trying to get my door locks re-key'd to the new ignition key.

 

A locksmith should be able to rekey the ignition switch to your original key, and you would only have to pay for one switch instead of both doors. If you remove the lock cylinder and hand it to them it will be even cheaper. I don't think the key problem caused the computer to short out.

 

My parts shelf ford dealer friend says the za is the earlier version of your computer and will run your truck. I guess the zb has a more aggressive lean burn mode for highway driving that may yield 1 or 2 mpg on a long haul.

 

Thanks for the re-key tip and the "ZA" vs "ZB" comparison. I plan to install the ecm soon, and will post my rsults.

 

Installed the ecm tonight, and it started right up. Guess the salvage yard (even though they stated "the part numbers match" when they didn't) gets a "pass". Hope my gas mileage doesn't suffer, as it wasn't all that great with the old ecm!
But I'm happy to be back running! Thanks to all for your input!

 

If you have door keys that are different from your ignition key, go to a lock smith and have them cut one side of a key blank to match your door key, and the other side to match your ignition key. Cut a notch or mark in the edge of the key and then you know how to insert the key into both locks.

The locks and ignition only have tumblers on a single side.

You can also do this if you have two different fords (bronco and a truck) and want to use one key for both vehicles.