94 Explorer VIN X V6 runs for a minute and dies

[budwich]

I am not sure I understand your "The 211 code requires at least 2 starts/runs before it's generated. So the multiple start/stop cycles helped it to return." statement a couple posts back. does this mean that the 211 came back after the 12 start/stop cycles or after the 12th cycle and then it would not restart and hence the code?????

 

[jadams]

anyways, your testing was what I kind of expected. The reason... you never lost PIP in those 12 starts so the system didn't have to try to "recover" from this "problem"... hence your "successes".

Was this due to the short running duration, like 5/10 seconds?

Now for some "real testing"...... I bet you can make your system not start after one start and "stall" by doing the "original" test that I suggested.... that is, start your vehicle and then disconnect your ckp sensor. If it stalls fine... reconnect and try the sequence again.

It dies immediately, tried it 4 times and same results each time.

If it doesn't stall, hopefully you can take some of your measurement "observations" to see what is happening. I suspect you might get one or two attempts, then you will be stuck for your "hour" wait... maybe.... ;-) To speed things up thereafter, you might try and disconnect your PCM module and then reconnect (don't know how much trouble that is... but you've been there done that so you are "well trained"). See if that helps get you "starting" more again.

I now have the cover off the PCM so I can see the innards/IC and I can remove and reattach the PCM fairly quickly, 15/20 seconds or there abouts. Stuck a socket on the drill using low RPMs. Since I have the cover off the PCM I removed it and used compressed air and sprayed it over the components, to quickly cool them, then reassembled it, but no start.

IF so, that tells me that your PCM is "doing something" and that something that I think it is trying to do is LOS mode but it isn't successful and hence your problem... my "conjecture".... from readings as in my "readings", I see that the system tries to "re-sync" if it loses PIP and failing that falls into LOS mode.... of course, the "readings" weren't specific to explorer's or years but it does make sense that you don't want "out right failures" of computer controls... just like "fly by wire" systems have some "smarts" to work around a few things.....

Anyways, if you try this sequence, I think you move your "stone" a little further down the road.

Have I moved the stone far enough? I now have a schematic of the PCM, but as bam_bam1ca pointed out that may be beyond my skill set at the moment, but then again four weeks ago.....

PS.... what you really need is a "dynamic test" ... basically an analyser on the PIP train.

I don't suppose that is something easily acquired/made?

Thanks

Jim

 

[jadams]

I am not sure I understand your "The 211 code requires at least 2 starts/runs before it's generated. So the multiple start/stop cycles helped it to return." statement a couple posts back. does this mean that the 211 came back after the 12 start/stop cycles or after the 12th cycle and then it would not restart and hence the code?????

I had the 211 code, PIP signal, before then cleared it and would start the car and let it run while I took measurements and made observations. I was doing KOEO tests and sometimes without restarting the car. Naturally I had cleared it a couple of days back. Today was the first time I ran the KOEO, the number of start cycles is irrelevant, but at least two are required before the 211 code can be generated. I assume it may have been generated in between 1 and 12, but may also require the car to die/stall before generation, the details are somewhat vague on that point.

 

[budwich]

Thanks for the info.... the stone continues to roll ... I think. Now we know that removing the PIP signal causes an immediate stall and that from that immediate stall, a reconnect and subsequent start can be successfully accomplished.... for a couple of more times at least... before you get to no "start". It certainly does appear that there is no LOS mode.... :-( however, there appears to be some "strange lock up mode" but not necessarily caused by a lose of PIP since you have been able to reconnect and do a couple of more starts... hmmm???? "It's not looking good for your hero" ... the PCM ... and your wallet...

One last bit of testing when / if you can get it to start. actually, it depends on what you got around the house and whether your wife will let you play with it... do you have a hair dyer / heat gun? I would go with trying some "pointed heating" at the ICM first and the pcm next to see if you can cause a "heat / usage" simulation stall. Of course, it would have to be quick since your "windows" seem to be about 4 minutes max. The other thing is the "wiggle test" with the most likely candidate, the ckp sensor / connector.... of course, heat on the ckp sensor is also good since its on the block already.... might hasten the stall... you hope. The stone is getting heavy...

PS... don't melt things but get them warm.

PPS... don't know but what the cost of an ICM? ... probably cheaper than PCM.

 

[jadams]

"It's not looking good for your hero" ... the PCM ... and your wallet...

Rather replace the PCM than the CMP, cheaper and easier. The ICM has been tested a lot and in quick succession to induce a failure. Didn't make any difference.

One last bit of testing when / if you can get it to start. ..... might hasten the stall... you hope. The stone is getting heavy...

PS... don't melt things but get them warm.

It's in the no start mode right now, I'll try that soon.

Can barely lift the stone now ...

 

[budwich]

The error code (211) doesn't suggest the CMP as a potential problem since it isn't in the PIP circuit but you never know I guess. I, too, am disturbed by the long time between ultimate failure to start and to successfully start again.

sorry for the back track but I going on 96 info which says that my PCM and ICM are integrated... i take it that in 94, they are two seperate components????

Having said that (using 96 info), in my "travels", I see that in some other ford systems, the cmp sensor IS used to mark cylinder one for the system in terms of timing / injection... hopefully not how your system is working.

 

[jadams]

"It's not looking good for your hero" ... the PCM ... and your wallet...
The stone is getting heavy...

PS... don't melt things but get them warm.

PPS... don't know but what the cost of an ICM? ... probably cheaper than PCM.

YOU ARE NOT going to believe this!!!!!!!!!!!!!

Stuck the hair dryer on the PCM, started the car took it to 1800 RPMs (simulates 55mph). It ran for 18 minutes.

After holding the hair dryer for 10 minutes it become too hot to hold so I shut it off. Sprayed some compressed air to cool the PCM, but it was very very warm. Ran it at the 1800 RPMs for another couple of minutes then let return to idle and it ran for another six minutes very smooth. Then missed a couple of times and died. Touched the PCM and it had cooled considerably, well at least I could touch it.

I can't lift the stone, why????????

Kinda shoots the whole overheating thing in the butt! A simple hair dryer, who would've thought.

 

[budwich]

While that's great... I think.... get out of the way... that stone is going to roll over you. By heating things up, you may have helped the components.... so it might not be a "usage heat" problem, it might be an expansion problem as in circuit board crack or a bad connector. The "board expansion" might be caused by some components warming causing a "minor" shift in the board / track. Your "massive heating" may have been such that the board / track fully expanded and was good til it cooled a bit. The heat would certainly help any connectors expand so that they are fully contacted.... maybe some "contact grease" is needed. Lastly, components like capacitors like a degree of heat to operate happily especially if they are marginal.

I would do an inspection on the board looking for cracks / cold solder joint... they don't look shiny but are "frosted a bit"... usually means "bad things".... can be fixed by resoldering or hitting with a solder iron. Before going there, try getting some "dielectric grease"... I think that what they use to prevent moisture, corrosion, etc in the contacts and see if that helps.

 

[jadams]

PCMs and hair dryers

Now the question become why would heating the PCM to the point it is too hot to hold allow the car to run longer, significantly longer. Besides expanding contacts what else is there?

I suppose now that I'm over my initial euphoria I should heat it up, the PCM, to see if it will start.

OK I did

Tried to start it, wouldn't start.
Heated the PCM and it started, ran for 15 minutes varying the RPMs and smooth as kitten. I kept heating it up with the hair dryer every few minutes. Shut it off. Started it up again without touching the accelerator.

As soon as it cools down I'll remove it and do close inspection of board.

 

[budwich]

now all you need is a very long extension cord so that you can run the hair dryer while you drive...

 

[jadams]

now all you need is a very long extension cord so that you can run the hair dryer while you drive...

I'm up to 225ft.

Just inspected the board, nothing comes back as obvious and I used a big magnifying lens. No cracks, loose connection or such that I can see. This is a problem that got progressively worse starting a couple of months ago. More like something going bad than something loose. Don't capacitors behave that way?

 

[jadams]

Sorry, I kind of got lost in the thread. Did you say that you replaced the ECM? I have read another thread where a member's truck would run for a while and then die. He eventually took apart the ECM and replaced the electrolytic capacitors in the ECM which fixed his problem. It is possible that the problem is related to a leaky electrolytic cap that will charge properly when first powered up, and then lose it's ability to store charge as it heats up. Metal can electros have an expected service life of 5 years, and anything past that is a gimme. I'm not saying that this IS the problem, but it is definately something to suspect, but unfortunately if you are not "into" electronics the only way to test for this would be to replace the engine control module.

I'm now at the stage where this type of information would be useful as the problem has been identified as the PCM, I hope.

 

[budwich]

well.... now that you are close .... don't forget that last test.... the wiggle test. get it running and see if you can break it with a wiggle.... related to that, I use a chop stick to "gently" poke at boards to shake them a bit to help with intermittent failures for loose components and cracks.... just tap around here and there and see if you cause something to happen... of course... "gently and carefully" not to cause shorts against anything like standing components,etc.

One last thing.... not that I don't believe the post about "caps" but 5 years ain't going to cut it. "Everyone" here would have gone thru a couple of PCM's already.... In general, if you look at the number of problems to fixes, PCM's aren't at the top. my 96 and .02 cents worth. To help focus your looks, my 96 drawings (general boxes) shows that pin 2 on the icm has the PIP going out towards the PCM (doesn't have a color or tell me what year the general diagram is from) but perhaps that will give you a color to look at... then track that color over to the PCM and check around that pin / circuit area for a problem... my "block diagram" does give me anything there and 96's don't have icm... the ckp stuff goes direct to the PCM.... as far as I can tell.

Related to your "heat test"... one other component that like a degree of heat is the crystal oscillator circuit used to drive the clocking for the chips. It will look like a capacitor and if you lucky you might see it identified on the board. Odds are not though as a lot of that stuff usually has metal shielding around it.

PS... Going bad to worse isn't necessarily a component problem... in general, caps usually fail out right and usually never recover. getting worse is usually a corrosion / oxide issue or changes with temp / humidity crack problem. Look at all the battery cable problems this forum sees (a fordy thing). One other thing... again mentioned earlier by some one... grounds... they like heat expansion.... is it possible that your heating might have helped a local ground some where near the PCM (ie. "heat spill over").... just a thought.... again wiggle, wiggle, wiggle.

 

[jadams]

well.... now that you are close .... don't forget that last test.... the wiggle test. get it running and see if you can break it with a wiggle.... related to that, I use a chop stick to "gently" poke at boards to shake them a bit to help with intermittent failures for loose components and cracks.... just tap around here and there and see if you cause something to happen... of course... "gently and carefully" not to cause shorts against anything like standing components,etc.

One last thing.... not that I don't believe the post about "caps" but 5 years ain't going to cut it. "Everyone" here would have gone thru a couple of PCM's already.... In general, if you look at the number of problems to fixes, PCM's aren't at the top. my 96 and .02 cents worth. To help focus your looks, my 96 drawings (general boxes) shows that pin 2 on the icm has the PIP going out towards the PCM (doesn't have a color or tell me what year the general diagram is from) but perhaps that will give you a color to look at... then track that color over to the PCM and check around that pin / circuit area for a problem... my "block diagram" does give me anything there and 96's don't have icm... the ckp stuff goes direct to the PCM.... as far as I can tell.

Related to your "heat test"... one other component that like a degree of heat is the crystal oscillator circuit used to drive the clocking for the chips. It will look like a capacitor and if you lucky you might see it identified on the board. Odds are not though as a lot of that stuff usually has metal shielding around it.

PS... Going bad to worse isn't necessarily a component problem... in general, caps usually fail out right and usually never recover. getting worse is usually a corrosion / oxide issue or changes with temp / humidity crack problem. Look at all the battery cable problems this forum sees (a fordy thing). One other thing... again mentioned earlier by some one... grounds... they like heat expansion.... is it possible that your heating might have helped a local ground some where near the PCM (ie. "heat spill over").... just a thought.... again wiggle, wiggle, wiggle.

I checked that ground near the PCM and it checked OK and was tight, but worth a recheck as it is one of the main grounds for the PCM case (and common to the fuel pump sender) The other grounds are terminated at the battery ground.
I have an EEC IV schematic and have identified everything related to the PIP circuit, unfortunately the quality of the JPG is not so great, the components are labeled :
Pin 56 PIP and goes to C7 (capacitor ?).
Pin 4 IDM goes to C109 a very tiny square thing with VA4 on it.
Both of these go to Y1E (on the schematic), an oblong silver metal canister type component with 2 pins, but this doesn't seem right because because the schematic shows 2 inputs and 2 outputs but with other stuff attached.
The outputs correspond to the IDM and PIP and both go to the processor. The PIP branches and goes to IC4/1 which branches and to a bunch of other stuff.

So what is a crystal oscillator? The components are delicate I agree. Chopsticks? Two of the mounting screws are soldered over. I was going to desolder them and check the pins. Too soon for that?

Should I reassemble the PCM and heat or not heat to do the wiggle test with the engine running?

 

[budwich]

you are moving right along.... crystal (oscillator).... its basically a piece of quartz crystal that when a voltage is applied across it, it causes an oscillation at a specific frequency characteristic to the crystal.... 4mhz say... that signal is then fed to a circuit which may "cut it up" in some form to make a clock circuit to drive / clock data for chips and such (general logic). New circuits may be all solid state but older ones may use a crystal. Its usually a little silver can.... my circuit design limits are being pushed here so take it with some "grain of salt". Crystals aren't necessarily very temperature stable and can drift but circuit design usually can accommodate this to a degree.

I can seem to find my "block diagram of the circuit" but the PIP and IDM are directly related by either an inversion or "square wave" equivalent sort of thing.

Anyways, in terms of the wiggle testing.... if possibly, I would go without reassembly...Ie. so you have access to the box without harming the circuits (ie. no touching other things). It would be nice to have the engine running (so enough heat to cause that but again don't "heat damage" anything). Then, poke and wiggle to see if you can cause a stall.... hopefully before cooling gets you first.... it may be hard to tell so if you cause a stall, you will have to try again to repeat it to see if you can reproduce or if it is "coincidence".

PS. yes "C" are capacitors.

 

[jadams]

you are moving right along....
I can seem to find my "block diagram of the circuit" but the PIP and IDM are directly related by either an inversion or "square wave" equivalent sort of thing.

Anyways, in terms of the wiggle testing.... if possibly, I would go without reassembly...Ie. so you have access to the box without harming the circuits (ie. no touching other things). It would be nice to have the engine running (so enough heat to cause that but again don't "heat damage" anything). Then, poke and wiggle to see if you can cause a stall.... hopefully before cooling gets you first.... it may be hard to tell so if you cause a stall, you will have to try again to repeat it to see if you can reproduce or if it is "coincidence".

Set the heated PCM up this morning with the covers removed and did the wiggle test. Nothing happened, it kept running, 22 minutes. Removed the hair dryer at 20 minutes and it died a little over 2 minutes later, which is what was occurring before, timewise. That it died quicker was, I assume, because I removed the thick aluminum bottom case that help retain heat to the board/components. With the bottom case attached it would run for 5 or 6 minutes after removing the heat vs the 2 minutes without the bottom half of the case.

Same results both times with case bottom removed. Wiggled and tapped the harness, components, and case sides with no change. I inspected both sides with an 8X Lupe and didn't see anything that popped out as a candidate. The whole assembly has a clear rubber film front and back making it somewhat difficult. As for cold solder joints and burnt appearances I saw some very faint discoloration in one area and few pins that may be cold solder joints, but kind of hard to be 100% with all the rubber coating.

Being careful with that stone too....

 

[budwich]

well, you just about used up all my "tricks". The coating is there for corrosion / oxide protection... more than the usual home electronics. I guess it depends on your "electronic skills" and the circuit layout / diagram. As was suggested by another, you could try replacing some capacitors in the "circuit of interest". You would have to scrape the board "gently" to access the solder tabs and then later use hot melt glue to cover them up. Assuming you can determine the values for the caps of interest... of course, they can be tested with a meter once they are out of the board.

One other thing is you might want to try "pinpointing" your heat with some form of tapered nozzle so that you can aim it at a location... might help. A nozzle might not be right as you might direct everything there causing a "rapid burn".... try something more like a hole in a "shield" (metal).... so that some heat goes thru the hole to the location and the rest goes else where away from the board. Just a thought as my ideas are running low.... but at least you are very close. Oh... one more thing, are any of the chips in sockets? You might want to consider reseating those... again very carefully... not sure with the coatings how that happens????? you need a "lifter" to pull an ic (with the module unplugged of course).... basically levers at both ends of the IC so you don't bend it "too much" by lifting one side and then the other. So close......

 

[jadams]

The coating is there for corrosion / oxide protection... more than the usual home electronics. I guess it depends on your "electronic skills" and the circuit layout / diagram. As was suggested by another, you could try replacing some capacitors in the "circuit of interest". You would have to scrape the board "gently" to access the solder tabs and then later use hot melt glue to cover them up. Assuming you can determine the values for the caps of interest... of course, they can be tested with a meter once they are out of the board.

One other thing is you might want to try "pinpointing" your heat with some form of tapered nozzle so that you can aim it at a location... might help. A nozzle might not be right as you might direct everything there causing a "rapid burn".... try something more like a hole in a "shield" (metal).... so that some heat goes thru the hole to the location and the rest goes else where away from the board. Just a thought as my ideas are running low.... but at least you are very close. Oh... one more thing, are any of the chips in sockets? You might want to consider reseating those... again very carefully... not sure with the coatings how that happens????? you need a "lifter" to pull an ic (with the module unplugged of course).... basically levers at both ends of the IC so you don't bend it "too much" by lifting one side and then the other. So close......

No chips are in sockets. I tried to remove the coating in a couple of places that were safe "it ain't easy" to say the least. Also there are ICs on the side casing that are attached with adhesive so it is unlikely I can remove them without damaging one. I would really need to do this inorder to access the the pin/PCB joints.

I had the 211 code "erratic PIP signal" so it must be a component that when cold, or at the normal temperatures that the board will reach, behaves in an erratic manner. BUT when heated to a much higher operating temperature behaves as it should. I realize the 211 code is fairly vague and broad, but the circuit controlling the injectors is the PIP circuit which receives input from the CKP and CMP to make its decision. So whatever happens or however it happens it shuts down all of the injectors, my EEC IV schematic does not show any of the output circuitry just the inputs.

Can a solder joint pin/PCB do that? I do get an uncontrolled amount of spill over in heat when I aim it at the board, it is a hair dryer after all, and since it is a forced air type unit how small of an area could it be concentrated?

So close.....and yet

Jim

 

[budwich]

ok... if the chips are all board mounted / solder then there is no "re-seating" and typically "solder-ins" don't have a problem.

Basically, when you lose PIP to the PCM, the PCM stops generating a SPOUT to ICM which causes things to stop firing which cause other things.

Your question about the "response" to heat and then die as it cools / runs is tough because we don't know the exact nature of the "thermal trace". As you have found, letting things sit for a "long while" assuming totally cooled to ambient air temp, allows you to start and run for some period. Then as the circuit works which I assume brings on a degree of heat causes the circuit to "soft fail". Heating to a "cosy temp" allows things to work fine. I don't know... lots of possibilities I guess... transistors, IC's to some degree, capacitors maybe, and even resistors... but ultimately, I still feel it is a cracked track / cold solder which is a good "thermal type trouble". As the board or component expands during use, the expansion difference from non-uniformity of heat (ie some areas / components are cool while others are hot ... by large resisters / transistor with heat sinks) puts stress on things. "Uniformly" heating "everything" may result in greater expansion overall such that connection is never lost from the smaller "non-uniform heating areas".... I don't know.... I think this is like one of those "I know **** when I see it" things. I will give you an example... take a resistor, as it operates, it heats up, this causes the resistor to "grow" in length... it puts a stress on the two attachments... if one of those points has a problem and "lifts" just a bit or it cracked, the expansion forces might be just enough to cause a loss of connection and you go from there. However, with your "massive heat blower", the overall board now expanded probably a lot more than the expansion of the individual component and thus that "massive expansion force" prevents any circuit "breakage" and you have no problems... ...:-(

If I had the module in front of me, I could probably narrow things down better. Do you have any electronics friend that can take a look at things a bit now that you know a bit more about the failing operation and circuit flow????

OK here is another idea to help try and sectionalize things. Maybe you can build some form of "air dam" (card board or something) to block the heat / air from say half the board and then try and see if you can find an area that will help a no start condition, turn into a start and run. As you see, I am almost running dry of ideas.... sorry... but my head hasn't given totally up.

PS... those IC's on the side of the case sound like transistor packages and are using the case as a heat sink.... you might want to aim at those specifically and see if that helps.

 

[doubledflooring]

Well I believe it is time to either replace the PCM with a new one or go to the junk yard and test the theory of a bad PCM for 35.00-50.00