So my 93 Ranger 4x4 has been giving me some trouble, rough idles, hard starts, intermittent check engine and I get almost no throttle. Fuel economy is absolute trash at 30 liters/100km (7.8mpg). Did the bypass and counting flashes and came up with the following. Have cleaned the IAC, new fuel injectors, EEC relay, fuel filter, fuel pump and spark plugs.

12: Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) – ISC

15: No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test Failure)

111: System checks OK

512: Memory power (PCM pin 1) was interrupted – Was battery disconnected ?

I haven’t the faintest clue how to go about looking for each of those problems, let alone fixing them, my tools, knowledge and experience are almost non existent. Taking it to a shop is most certainly not worth the fortune it would cost. So, where can I go from here?

 

Welcome to the forum

The computers used either 2 digital or 3 digit codes not both(OBD1), 1995 and up used 4 digit(OBD2)

1993 should be 3 digit

Ford 3 digit code list here: https://www.therangerstation.com/tec...gitcodes.shtml

So
111: System checks OK
512: Memory power (PCM pin 1) was interrupted – Was battery disconnected ?
Are correct
512 just means battery was disconnected at some point in the last few weeks, it will clear itself after a few more "drive cycles" that's one heat up and cool down = 1 drive cycle

And what size engine do you have, 2.3l, 3.0l, or 4.0l?

1993 Computer might need 3 new capacitors, under $5 to fix , causes running issues but nothing specific and codes to show up but no correct codes, free to have a look inside the computer

My 1994 4.0l computer had 2 bad caps, changed all 3 last year and its running better than even, kind of snuck up on me over time, just odd stuff then it got worse
The Blue cylinders are the 3 capacitors, replace with Black ones of same value/voltage, they do have a polarity, +/- sides
I pushed over bottom one with finger its wires were corroded and the top one as well

 

It’s a 4.0. As far as I can determine it was originally a 3.0 that was swapped over at some point in its history. Don’t know if that makes a difference.

I’ll have to take a look. How did you replace them? Just bought new capacitors and soldered in place?

 

I have the same 3-digit trouble codes.
the 1-1-1 first means there are no active codes. The second set is for stored codes. So that 5-1-2 is something that may not have been current just a code that was triggered at some point and stored to memory.
I check all 3 code sections. Active codes, stored codes and then koer codes. First is when you turn key on it runs a system diagnostic to see if anything pops up, sensor disconnected type thing. Then it will pause 5 seconds and display stored codes. I usually clear these out after logging them just to see if it was a fluke. If they come back after driving around.
then I start engine and get those codes after goosing the throttle.

 

Yes, take pictures of the Caps so you have a record of Value on the side. i.e. 47uF 63v, and also the "-" side, has a stripe with "-'s", and which one goes where
Then you get replacements of same value, the "v" is voltage and can be higher but NOT lower, so 47uF 100v would be OK, 47uF 16v or 47uF 50v, would not be OK

You need a solder "sucker", just a spring loaded tube that can suck solder out of the hole/wire once its heated up
There is a clear resin over the whole circuit board, on both sides, in my picture you can see the little white spots, that's the resin, it just melts off with soldering iron so not in the way
Not needed, but if you want, you can apply clear nail polish over the places the resin was removed by soldering


Look at your VIN number, bottom corner of drivers side windshield, or on the sticker/label on back edge of drivers door
8th digit in VIN will tell you what engine came in your vehicle from the Ford Factory
U or V was a 3.0l Vulcan V6
X was a 4.0l OHV V6
A was a 2.3l 4cyl SOHC Lima engine