Proper diagnostics depend on doing the tests in the proper sequence.
Codes for the KOEO self tist will be output before any continuous memory codes.
Fix any KOEO codes first (in the order given), clear the PCM continuous memory codes, go for a drive, and then and only then tackle any continuous memory codes set.

If KOEO givea a code related to the temp sensor, then find out if the sensor is really bad or you have a wiring/connector problem. The sensor is nothing more than a resistor whose value changes as the temp increases. A good first shot would be to measure the resistance on a cold engine, then again on a warmed up engine. If it has changed, then one could assume the sensor if functioning to some extent. If so the go for the wiring/connectors. Measure the same at the PCM wiring harness to verify wiring/connectors. If it looks good there then most ikely the PCM is faulty.

In short, break the trouble down into its most basic elements and eliminate them one at a time. Once you fix one thing, retest the system again and repeat the process.

 

I'd trash the paper clip diagnostics. This poster is new to this stuff and though an experience eye can properly read with a paper clip, hell i wouldn't even try it. Get a good scanner on the thing and do KOEO, KOER tests and then let's see what you really have. If there are so many low voltage circuits being reported...and it happended bam all at once, it's either a power delivery issue or a bad PCM. All that stuff all at once? I'd look for a smoking gun an not a trial and error through the numeric codes. My 25 cents worth.

 

I agree with MrSki - as I was saying all along - either get a decent OBD1 scanner, or have them read...

But, if you can get a good used PCM - I'd maybe try swapping it out first - if you still have all those same problems, it's most likely a wiring problem (harness has shorts, etc)

The paper clip deal is good for a single code, or maybe a couple - which might be all you have in the first place, and a good reader will tell you for sure.

 

I've tried finding a scanner, they do not sell them locally for obsolete vehicles and if they did it would only work on this truck. I fear I've landed a Chevy-Vega type vehicle that will keep leaving me stranded and crack a block one day "just because".

Others have warned me against diagnosing the problem by buying new parts one after the other. There is more wiring and sensors and weird parts in this vehicle than in Battlestar Galactica...how many thousands of dollars should I pay to fix an unreliable design?

I might try to see if I can rent a reader or find a mechanic willing to come by and read the codes. I am fairly sure the codes will be the same, though, and no progress will be made.
Hopefully somebody will know the most likely cause and a magic cure can be found. The most likely cause approach seems the best way to go at it, don't ya'll think?

Now if anybody wants a truck that was literally mostly driven by an elderly couple and only has 85,00 original miles and looks new-ish for about $1,500 it's yours!

 

I have an Equus which has seen good service and was worth the $30.00, saved more than that in heartache and parts, I am now saving you the bother to search for one.

I personally hate throwing $/parts at a problem, until I diagnose the problem rationally

http://www.tradervar.com/cgi-bin/sto...&page=3145.htm

or this one

http://www.tradervar.com/cgi-bin/sto...age=cp9015.htm

Do yourself a favour, quit bitching about the help you are getting and/or percieving not to get, do some serious diagnostics.

Remember the Lord helps those that help themselves.

My 2 cents.

 

Gbas - Sure I'll buy it for $1,500! Now that I know who to work on these...practiaclly completely rebuilding mine up to now.

But if you want to "learn" how to fix it and diagnos it, it's really not that complicated and can be very rewarding once you get the "beast" figured out.

The PCM is just a computer running a program. It's got inputs and outputs just like a PC. It responds (outputs) based on the inputs given. Thus the engine control system is equiped with sensors for inputs and actuators for outputs. When all the parts are working togethre correctly, the motor runs nicely. I've got 180K on my motor now and it's got just as much poer as it did when I bought it new.

I've asked you to PM me your email before and I'd send you links so you can go learn this stuff. So far you've not responded. I'll try to post some links but I'm sure the posting gods will squash them.

 

Try this for basic PCM operation. Generic but use this with a schematic (off autozone web page) and you can easily figure out the controls system.

fordfuelinjection.com

 

There's one got caught...try it again.

draco.acs.uci <dot> edu/explorer/

 

I just bought a 96 Sport for $500, so I can't complain - 100K - needed to be washed and waxed

Gbas - it's like everyone is telling you - you need to find out the root of the problem - we are all trying to help you, but you have to give us more than what you have given us, or it's really anyones guess - that's my final feeling on it, and I agree with aqua... I used to work in Tech support, and we'd always get people that would call us back, without even trying to make things better on there own, after we'd spend 1/2 an hour on something that they could have read in the manual - of course, now, you can't even call support for anyone anymore, unless you can speak whatever language they do - it's sad.

 

Edit, edit, edit...forgot the dot between the uci and the edu

 

LOL!!!

 

I have spent much time reading the manual and searching for signs of burned wiring, disconnected stuff and I have replaced the Idle Control Valve. I bought the security torx keys to check the (spotless) MAF sensor. I have counted the darn flashes of the Check Engine light over and over to make sure of the codes. All to no avail. I am not just "bitching" (not about the help BTW, about the truck, I appreciate the help). I am asking for help in hopes of not spending however much time it would take to learn all about the truck by myself...is this bad?

The codes by the paperclip method are the same codes a reader would give, aren't they? Why would a reader be better? It's just quicker, or am I wrong? Does it give more than just the codes?

The truck does not run anymore BTW. It has a new nickname based on the movie "The Gods Must Be Crazy"...it's "antichrist"!

I will read all the stuff you suggested and see if I can get more clues and learn where all those sensors are...

Again, thank you.

 

The bottom line is, you have to rule out whether or not you have a faulty PCM - It's that simple - That's where you need to start - no one on here can do that for you - many have tried to explain that point, but all you want to do is start replacing sensors based on all the codes you are getting, which can get expensive both in time and money, and you might end up right where you are now after you are done, since you don't even know if you have legit codes, or bogus codes from a bad unit...

It's common sense that it would be VERY unlikely that you actually have 10 codes or however many, as legit codes, and the fault of the sensors, with a perfectly good PCM - but it's possible.

a decent shop will pull the codes for you, AND test the PCM - even if you have to tow it there - at least, then you'd know what's going on to start with.

If you have them pull your codes, you can compare what they find to what you found with the paperclip test...

I really think it's a very simple matter of just verifying that you have a good PCM in the Truck or not - you could try swapping it for another one, if it would be cheaper than having someone test it. either way, it's your first step I feel, as do many others that have followed this so far, and have told you their 2 cents worth...

 

Here's a link for a computer for a '93 for $35 plus $10 shipping. The seller has 100% feedback rating, so I don't think you can go wrong.

http://tinyurl.com/mb25n

email the seller and ask him for the code on the computer. I'm not sure which numbers have to match up with yours, but I think MrSki already posted that info, or he could just post it again. If the numbers match, $45 ain't much to rule out your computer.

 

The TSB I have is for the 1993 model. Some 10 or so PCM numbers got upgraded to 1994 model numbers. So it is possible this PCM has a sister model number that will work as well from a 1994 car. The upgrade was just to richen up the cold start and cold run profiles to prevent a stalling condition when you put it into gear cold. No big deal. The rest of the PCM tables remained unchanged.