i have a mazda ford, its a 94 2.3 b2300 PU, im sure you guys are aware, its a ranger in disguise, and way here we go.. bout two months back i was driving out of town,, i pulled out from a red light,, ( it has been running fine till) and it stopped dead,, i cranked it for an hour and killed the starter.. anyway i was towed in to a local shop.. they checked it out and said that first it was a crank sensor, so they replaced (twice) the first one they suspected was faulty from the parts store.. still wouldnt start. so they kept going, and decided that it was the pcm.. ok well i found one at a pcm rebuilder for a reasonable price, but after the pcm arrived at the rebuilder, they claimed it was burned to bad to repair, so they sent me one that was supposed to fit and be the right one.. well it came, got installed and still says its bad.. per the mechanics.. so i let them send it to cordone to rebuild, which they did and it still did the same thing, no spark, or injection pulse ... well they kept lookin for two months, they couldnt figure it out,, but they did find that if they grounded the crank sensor it would run, so i brought it home.. a lot of cash for nothing in my book but it was over 70 miles away, i didnt think i had a choice.. well now it gets interesting,, the wire to the crank sensor that is supposed to be grounded reads that it is,, but it wouldnt fire.. so they grounded the wire,, pin 16 on the pcm, its orange with a red stripe,, with this grounded it runs..(this was only to get it home) but i noticed that the tac dont work so good.. now when i start it.. it stalls out and gives a code sometimes, tps usually..and the tac works, but it revs up nice and then as it slows down it stalls, if i dont clear the code it wont start,, then the next time it backfires , and the code goes away and it runs but the tac dont work?? lol really weird.. so im really at a loss, i am a mech, but im not to healthy so i can't test it out for long.. now i dont know if the pcm is good or not now.. the case of the pcm is grounded, dont know if its supposed to be or not.. and i did get a 998 code , but i was told that was because i didnt do a koeo test and just tried to start it.. it has new wires, new cranksensor, new icm, and thats bout it... any ideas would be great, or even info were i might find a pcm that is know to be good..
any way ask away, im sittin here waiting for some feedback..

 

so now i have another question, they seem to have sent a pcm for a ranger.. now i know there supposed to be the same vehicle, but my pcm is F4PF12A650UB, they sent a pcm #F47F-12A650-BDC are they truly interchangeable.. I was told it had to be part number of the original orit wouldnt work.. any ideas on that.. i see them sayin other numbers fit, but so far thats not the case?? there is supposed to be ground wire to turn on the crank sensor,, and icm.. another thing, i noticed that inside the pcm the board is F47F-14A608-HC i cant find any info on it?? nada like it dont exist..

 

Tinfoil could fix this car. Keep this in mind....
This is really a weird, deep problem that gives the impression that you will never really be sure that you've fixed. Keep this in mind, also...
This problem presents itself as either a grounding or Radio Frequency Interference (RFI) problem. However, you never really can be sure.
This is also Good, Old Fashinoned, EEC IV (second generation) that really wasn't too hard to keep happy. That's really good, but when there are spark problems, they can be really hard to diag and fix, like what's going on here.
I did a LOT of work on this system, and it's the old DIS system, high data rate, if I remember it correctly. It should use, and PLEASE correct me if I'm wrong because I could be, a seperate EDIS (elec. distrib. ignition system) module. THis system was very reliable, however, it was susecptible to RFI.
To start with, the 998 means there is a hard code being set when you were testing it, and you should have gotten a code, which would probaly be for something (like you said) TPS. ignore it for now. Worry about the symptoms first.
Start diag on this system by making absoultely, positively, beyond a shadow of doubt, that the CKP wires are clean, not shorted to anything (ground, power, or each other). These engines that used this system liked to leak oil, and the harness would soak it up and short out. Also, they should be loosely twisted, and be sheiled by a metal foil shield (like tinfoil, which I've used to repair it), which has to be seperately grounded. And yes, the PCM should be grounded (which is called the case ground), and while you're at it, check all the grounds to make sure they're clean and tight.
If this is all OK, then check the plugs and wires (and coil pack) to make double sure that there is no spark arcing to ground. Since these engines were gutless and needed two plugs just to move, they were prone to arcing to ground on the intake side, under the manifold, next to the head, and were hard to see.
Also, have you either checked or have any reason to doubt that the cam timing has changed?
Another quick check is to disconnect the alternator from the batt. terminal and the connector that goes into it, and run it, and see if it gets better. If it does, then the alterantor is defective.
Also, take out the SPOUT or SAW connector which was located about an 1 or 2 from the EDIS module. It is a two wire connector with the same color wire coming as going, which used to be something like pink/blk (though that was sometimes subject to change). Run it again and see what happens.

Check all this out, and let me know. THere are other things to check, also.

 

ok just a bit more info, yes when they pulled the crank sensor they put in a new belt..

yes your corrct tht it does have the icm on the front of the drivers side head.. i have the pcm out atm, i'll put it back tommorow and see what that spout does.. an do the alternator as well,, i'll get back early tommorow..

thank you for your assistance..

 

so here is what i did, put the pcm back in, found the spout that you mentioned, wont fire.. remember it has a wire that is connect to ground.. but it shouldn't be , garage cut and put it to ground. when its not grounded it shows a weak ground. does that mean that the ckp is grounded, not sure where all the wiring is grounded? even with a manual.. wth out the alternator it doses't fire.. should i connect the make shift ground, again it was cut and grounded to make the ckp show pulse..i'll hook up that ground ans see if that makes a difference, but it was never grounded there before so i tested it without that on .. wiring is my weakest point.. im a great engine guy lol

 

ok so i had to put the ground to the pcm back on the body,, (its a makeshift) and i noticed that they hd also grounded the pcm pin @20,, with out the spout it will run, slightly fst idle, but seems to settle down but shakes ..i got new codes, with a koer test,,511 538 521 411m looking them up; for whatever lol might help i didnt see a real differese with either the alt not being fed,, or the spout disconeccted.. just now i get this long list of the codes previously stated.

 

Well, let's make this easier. Disconnect BOTH terminals of the battery, and leave them off for the duration of this suggestion.
Do a simple resistance check with the pcm connector disconnected, at the pcm connector, find the 2 pins that go to the CKP sensor, and disconnect the sensor. Probe either pin with the sensor disconnected, and put the other end on the pos. battery cable, then the neg. battery cable. Any reading lower then about 5 ohms (that's Ford's spec, but in the real world it will be either very low or well over 1 milllion ohms) is a short. There should be no reading on either of these two wires to anything other then the CKP sensor.
THe 3rd wire is the sheild that goes around the two wires, which absoultely has to be grounded. This reading should be less then 2 ohms.
If they aren't reading correctly, then there is a wiring problem.
Also, I don't have access to a wiring diagram of this truck, but I'll try to dig it up at work and see what pin exactly you're talking about.
It would be worth it to make sure that all the ground are clean and tight.

 

well first thing i found is i need a wire piercer, i got one on order.. i tried what you said, i didnt see any thing,, it wouldnt even read, i tried to stick it with a pin, but i was tearing up the wire.. i did see the ground wire.. basically the ground to number 16 on the pcm is an orange with red tracer.. the grounds are black and one black and green ..the grounds see ground..and at the ecm the voaltage going in is 12.45,, odd thing is the orange /red at the ecm is grounded to case internallly..but only -4.0 volts, i gather that the ground is supplied by the ecr case itself.. however the case of the ecm is -12v but not the ckp ground wire comin out..is it safe to assume it should be 12v as well..

 

all right for some more information, i have been speakiing with cordone, they told me that the pcm that i have ,, ( was a replacement) is not the correct one for my vehicle.. its one number and only that number, i will purchase a new pcm and let you guys know how it works.. i knew that likelywas the case even tho the pcm i sent in was broken, they couldnt rebuild it and sent this wrong one back in its stead.. so basically i got ripped off by the pcm company, and as soon as i find it again, im gonna post it big as life..

 

i found the correct one.. took two months to track it down, plus two incorrect ones.. wow what a pain,, i'm not much of a fan of electrics on this mazda/ranger..