I just tried doing the self test for reading the codes via the check engine light with the OBD1 system on my '93 4.0 Ranger. Problem is: When trying to mark down the flashes of the check engine light, they flash so erratically and rapidly that there is no way to accurately count. At times the light flickers so fast it never even gets to get fully bright enough to tell if it is actually a "flash" or not. Any ideas? I'm (again) trying to diagnose an issue with the truck starting and running fine for about 3-4 minutes and then like flipping a switch begins blubbering and belching out black smoke, check engine light flashes on/off randomly, then the engine will eventually die. It will restart provided the ignition switch is turned all the way off and attempted again, generating same results only within 30 seconds or so. If you try restarting w/o turning the ignition all the way off, it'll spin over but won't start. ECM? Thanks in advance for any assistance.

 

You might try hooking up an analog multimeter to the under hood DLC & watch its needle swing, to read the codes, like done here http://www.troublecodes.net/ford/ or just come by a code reader, they're not very expensive now days. EDIT: Or if blinking lights & swinging meter needles are too much, hook up a 12 volt buzzer in place of the meter, or light & listen to the dots, or dashes.

 

If you happen to have a handy car to borrow from, I'd be trying a MAP swap. The MAP diddles with the load reported to the computer, so the computer can make the mix richer or leaner correspondingly. If the MAP dies, it will send lots of bogus signals that the computer responds to, and the result is an idle all over the place and black smoke intermittently.
If the smoke is more constant, I'd check the fuel pressure and regulator operation.
I have used an analog VOM at the underhood diagnostic connnector successfully as there is no cluster light(or connection to my knowledge) for my truck. I bought a reader about 15 years ago that uses a 9-volt battery and will buzz and light a LED to indicate the code pulses.
If you sort of count to yourself, e.g, by tapping with a pencil on a clipboard, in time with the 'short' pulses, you will be able to better count them as you keep time with the 'beat'. You can get them displayed multiple times without them getting erased.
I have seen the OBD-I Ford readers for around $10, which is a lot less than they were when I needed to get one. An analog VOM may not be able to keep up with the pulses, and you have to pay attention. When you first start up the code process, it will blurt out all the codes in one burst, which you can ignore as that is / was used by the Ford diagnostic machine, (Oasis, I think), getting all the info in a short period of time.
If you disconnect the MAP, I think the idle will clean up a bit as it may use a 'limp-home' table of values. If you disconnect the regulator vacuum line, and smell fuel, replace the regulator as the internal diaphragm is likely ruptured.
tom

 

Thanks guys, good suggestions and are greatly appreciated. I've been grabbing at straws with this truck. I definitely want to take care of it as I inherited it from my father just before he passed. He said it was mine as long as I took care of it. I need to do just that.

 

To keep it in good repair, follow the scheduled maintenance call outs with the specified fluids, filters & parts that say they meet or exceed Fords specifications & enjoy the ride.