94 Explorer VIN X V6 runs for a minute and dies

[jadams]

His "pin probe" is made by taking a "straight pin"... sewing pin used to hold cloth together while you sew... ask your wife... basically its got a small sharp pin end and is strong enough to "pick" a small hole thru leads to test for voltage without really "disturbing" the insulation too much.

My wife would get a kick out of that one since I'm the who does the sewing. Well after I rebuild the engine anyway.

Interesting. It would appear that you are "almost there"... but maybe not. Lots of testing.

Yes, lots of testing, but at least now I'm beginning to understand how it all works together....but maybe not.

Anyways, if I follow some of the testing and "conjectures", its appears that the system starts to failing in terms of timing / pulsing. However, from "conjectures", supposedly if it loses pulse from the ckp, it should go into limp mode with a X% timing (sorry I didn't go back... but the actual value does matter... only the "conjecture"). My suggestion would be for you to put it into limp specifically.... that is when you get it started, have someone pulled the connector on the ckp... it should go quickly into limp (and you should also get a code). The system should still run... right???? at least for your "new record" of 4 minutes. My guess is your ckp is "dynamically bad" (which can't be tested statically) and / or the "missing tooth" on the sprocket has a problem.

So start the engine then disconnect the CKP while its running. Fortunately the belt goes in a direction where fingers or connector are not likely to caught. The missing tooth looks OK. So how long should it run ? What will this tell me, I've already replaced the CKP once and no change?

One other thing that was mentioned is TPS.... there have been posts about a bad TPS causing a total shut down.... maybe after the system has "warmed up" for a few minutes, it starts to come off "system choke" and "reads" the TPS as being "fully closed" and starts shutting down fuel which starts shutting down the engine until it fails.

Well that's a new one, can that be statically tested? Here's something, my 4 minute record happens when it runs at 2000+ RPMs, but if it just idles maybe 2 minutes, I haven't actually timed or noted things like ambient temperature specifically. Other than it was than when it only ran for a minute and a half. The dying symptoms are always the same, the injectors quit intermittently then completely. After second restart, 3rd attempt, no start and signal to injectors intermittent or absent, hence no start.

Added: I see the TPS can be tested.

Now time to break out the sewing kit.

Thanks

Jim

 

[budwich]

well the CKP connector removal should tell you that indeed your system can be put in "limp mode".... and hopefully it will run different.... because you are not relying on any timing generation other than the PCM which should be fixed with no changes for temperature (ie. sensors), fuel mixture (ie. sensors), vacuum (ie. sensors), etc (... ruling out sensors maybe)... which should then get you to "basic operation".... hopefully. If it doesn't run and dies immediately, then you know you have a problem with your limp mode operation which might help eliminate a lot of stuff... IF it can be determine what limp mode is in terms of computer setup and what is actually happening from your readings when / if it dies. This is kind of like putting your computer is basic DOS without all the "windows plus stuff" to find out why its running so slow or blue screening ... now back to your sewing.

PS... you might also see some different codes

PPS ... I should have you "pryck" and not "pick"... you don't want to dig, you just want to "stick".

PPPS... the "statically" was in reference to a resistance meter and such.... the sensor is an inductor and inductance tests are not very easy to perform.... out right shorts or opens might be quickly found but whether enough "juice" is stored / created is pretty tough. It might not be a sensor problem but a connector issue so replacing the sensor isn't / didn't change that issue.

 

[MrShorty]

His "pin probe" is made by taking a "straight pin"... sewing pin used to hold cloth together while you sew... ask your wife... basically its got a small sharp pin end and is strong enough to "pick" a small hole thru leads to test for voltage without really "disturbing" the insulation too much.

Most of the time, I try to backprobe at the connectors (poke the pin into the backside of the connector alongside the wire until it contacts the metal).

However, from "conjectures", supposedly if it loses pulse from the ckp, it should go into limp mode with a X% timing

My experience, on my '92 included, suggests that there isn't a "limp mode" for loss of PIP. If you unplug the CKP the engine shuts down. A '94 may be different, I'm not sure. At this point, I doubt there's a limp mode for it. That's why I think a problem in the CKP/PIP circuit would be enough to explain the stalling/no start condition.

 

[wyochimneysweep]

Here i go. find the egr vavle and if it's vaccum operated unplug the hose and plug the end of the hose and see if maybe the egr is flowing egr. just a thought since you had it all apart. very easy to hook up a vaccum line incorrectly. it would start and run ok for a short time then start missing as more and more exhaust is flowed in and also expain why it will not start back up right away

 

[jadams]

Most of the time, I try to backprobe at the connectors (poke the pin into the backside of the connector alongside the wire until it contacts the metal).

My experience, on my '92 included, suggests that there isn't a "limp mode" for loss of PIP. If you unplug the CKP the engine shuts down. A '94 may be different, I'm not sure. At this point, I doubt there's a limp mode for it. That's why I think a problem in the CKP/PIP circuit would be enough to explain the stalling/no start condition.

Good advice on on using the backprobe at the connector base. Just tested the CMP circuit using this and the Mitchell specification 6.8VDC at idle and the rest below:

1. With the ignition OFF, disconnect the CMP sensor. With the ignition ON and the engine OFF, measure the voltage between sensor harness connector VPWR and PWR GND terminals (refer to the accompanying illustration). If the reading is greater than 10.5 volts, the power circuit to the sensor is okay.
2. With the ignition OFF, install break-out box between the CMP sensor and the PCM. Using a Digital Volt-Ohmmeter (DVOM) set to the voltage function (scale set to monitor less than 5 volts), measure voltage between break-out box terminals 24 and 40 with the engine running at varying RPM. If the voltage reading varies more than 0.1 volt, the sensor is okay.

Fig. 3: CMP sensor wire harness connections for the 3-wire sensor
VPWR - Black/White
PWR GND – Red
CID / CMP – Dark Blue/Orange

Both tests 1 and 2 came back OK. So now I'm back to why does it run for a short period of time and then the injectors loose their signal but I still have spark. Can start it twice OK, but the third time No Go. Just intermittent signal to the injectors, but had voltage that leaves the ground being controlled by the PCM. Also hooked up the DVOM to the injector and voltage was present even when the engine died (so not the ignition switch?). The CKP is also fine, does that leave the PCM? The ICM tested OK at Autozone, they let test it 20+ times in quick succession.

You were right on getting good reference material. No limp mode either, must've that started in 96 or with the beginning of OBD II

 

[jadams]

well the CKP connector removal should tell you that indeed your system can be put in "limp mode".... and hopefully it will run different.... because you are not relying on any timing generation other than the PCM which should be fixed with no changes for temperature (ie. sensors), fuel mixture (ie. sensors), vacuum (ie. sensors), etc (... ruling out sensors maybe)... which should then get you to "basic operation".... hopefully. If it doesn't run and dies immediately, then you know you have a problem with your limp mode operation which might help eliminate a lot of stuff... IF it can be determine what limp mode is in terms of computer setup and what is actually happening from your readings when / if it dies. This is kind of like putting your computer is basic DOS without all the "windows plus stuff" to find out why its running so slow or blue screening ... now back to your sewing.

PS... you might also see some different codes

Codes are coming back 111, system pass. No limp mode either.

PPPS... the "statically" was in reference to a resistance meter and such.... the sensor is an inductor and inductance tests are not very easy to perform.... out right shorts or opens might be quickly found but whether enough "juice" is stored / created is pretty tough. It might not be a sensor problem but a connector issue so replacing the sensor isn't / didn't change that issue.

See my post to MrShorty concerning the dynamic testing.

 

[jadams]

Here i go. find the egr vavle and if it's vaccum operated unplug the hose and plug the end of the hose and see if maybe the egr is flowing egr. just a thought since you had it all apart. very easy to hook up a vaccum line incorrectly. it would start and run ok for a short time then start missing as more and more exhaust is flowed in and also expain why it will not start back up right away

I labeled everything as I was taking it apart. BUT I tried anyway and no help. The car was missing really bad (though intermittently) and dying before the rebuild.

 

[jadams]

Look at it from this angle: why does it run for a minute - not why does it stop. In the first minute you're bypassing some components and running off a preset mode. It appears you're dying in the transition (actually a minute is a little late for that). Also, several types of component failures would send you to limp home mode, which you're not making it to.

For the basic components:

IAC can be bypassed by holding throttle open

All fuel delivery problems would appear in the first minute when you're feeding more fuel than later when you're feeding less fuel.

TPS is easily checked with voltmeter, and from experience the engine will still run if the TPS is bad and you hold throttle wide open.

Do the following and see where it takes you:

1. Plug the vacuum lines you don't really need. Definitely plug vacuum line to EGR (this is a Ford suggestion).
2. Pull plugs - how do they look.
3. Make sure you're getting spark at each place while cranking.
4. Do compression test just for the hell of it.
5. Watch it run with vacuum gauge and fuel pressure gauge hooked up. See other threads or manuals for what you should be seeing.
6. Check your air temp and engine temp sensors - they won't kill my '91 but maybe by '94 they cause a shut down - like the engine thinks it's overheating.
7. Start looking for things that might get hot and shut down - I've had this happen before with other vehicles.

I'm assuming with the upper end work you didn't touch anything that could affect timing, right?

Ben

Item #7 is what I've tried to isolate, no likely candidates yet. Nor did the gas cap help. The missing and dying were symptoms before the rebuild.

 

[budwich]

I didn't see where you tried the "egr stuff" that was suggested by ... chimneysweep.

One other question.... most of your reports are start, stall, start stall, no start... or there abouts. My question is what happens if you start and then key shut off "quickly" thereafter... repeat of that cycle... do you get more cycles.... hopefully without burning out your starter...

 

[bam_bam1ca]

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.

 

[jadams]

I didn't see where you tried the "egr stuff" that was suggested by ... chimneysweep.

One other question.... most of your reports are start, stall, start stall, no start... or there abouts. My question is what happens if you start and then key shut off "quickly" thereafter... repeat of that cycle... do you get more cycles.... hopefully without burning out your starter...

Sorry about that one, yes I did try the EGR stuff. No difference.

I will try your suggestion in the morning. Thanks for reminding me and Thanks to wyochimneysweep for the input.

 

[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.

No I didn't replace the PCM. I wish I had a schematic of the creature. I've had it apart and didn't see any of the usual discoloration that indicates a problem such as overheating or corrosion. I'm trying isolate the testing procedure for the PCM specifically as it relates to the injectors. The CMP tested OK and that leaves the PCM/Injector circuit as the CKP and ICM tested OK. I've gotten a little better at testing so I'm willing to give anything a try, especially after replacing good components and it not making a difference. I have voltage and resistance charts, but kinda lost track of where I am, though more and more it seems the PCM is at fault. Of course myself and others said the same thing about other diagnostic conclusions. I do not discount that I may have overlooked a suggestion or two, or not followed a suggestion correctly.

Thanks

Jim

 

[wyochimneysweep]

Yeah If It Was Missing Before The Rebuild Then Throw My Idea Out Unless It Is Physcially Stuck Open.

 

[jadams]

Yeah If It Was Missing Before The Rebuild Then Throw My Idea Out Unless It Is Physcially Stuck Open.

I took the EGR valve apart and cleaned it, plus it's only a year old. I replaced it then because the previous one was bad.

 

[OldSchoolFord]

It sounds like its time to check the ECU.(computer). I have a 92 Eclipse that had a bad ECU. Hard starts, ran like crap and put out codes that were false. It turns out , like mentioned in above post, the capacitors were no good. This was a common problem with the first gen. Eclipse. I found this place on-line called Motoguy's Garage.Mabey this guy can help. He rebuilds ECU's. The best part is(Listen Closely!), You can order a rebuilt ECU for cheaper than anywhere else and see if it solves your problem. If its doesn't, YOU CAN SEND IT BACK FOR A REFUND. It appears you are a point where you need to eliminate the computer as source of the problem. Check out the web sight
http://www.motoguys.com/

Good luck, Chris

 

[jadams]

It sounds like its time to check the ECU.(computer). I have a 92 Eclipse that had a bad ECU. Hard starts, ran like crap and put out codes that were false. It turns out , like mentioned in above post, the capacitors were no good. This was a common problem with the first gen. Eclipse. I found this place on-line called Motoguy's Garage.Mabey this guy can help. He rebuilds ECU's. The best part is(Listen Closely!), You can order a rebuilt ECU for cheaper than anywhere else and see if it solves your problem. If its doesn't, YOU CAN SEND IT BACK FOR A REFUND. It appears you are a point where you need to eliminate the computer as source of the problem. Check out the web sight
http://www.motoguys.com/

Good luck, Chris

Hi Chris

Went to the site and they don't have them for an Explorer, but great concept especially if it doesn't fix the problem return the part for refund. At the local Autozone I can I can order one for $155 plus $50 core. They aren't very knowledgeable (nor should they in all fairness) about the important parts like state emissions and transmission type so they could easily order the wrong one. For mine the part number is F47F-12A650-DBA (POX 0). The DBA means automatic transmission and California/New York emissions, not sure about the POX 0, or the emissions calibration code, but this was on a sticker on the PCM. I found a bunch with ADC, AXB and a few others, but those are for the Ranger/Mazda B3000 series.

 

[OldSchoolFord]

Call the guy at motoguy on the phone. He is friendly and helpful. Mabey he can point you in the right direction. (he might know someone that will test/rebuild your ECU)
Chris

 

[jadams]

One other question.... most of your reports are start, stall, start stall, no start... or there abouts. My question is what happens if you start and then key shut off "quickly" thereafter... repeat of that cycle... do you get more cycles.... hopefully without burning out your starter...

Just tried this start/off cycling. I was able to get 12 cycles and ran KOEO at the end and the 211 code reappeared. The first 6 or 8 starts I didn't have to touch the accelerator, each start after that a light touch was required to start. I checked the TPS for dynamic response with a DVOM and received the voltage variation expected from RPM change.

Apparently the problem is when something is getting warm/hot because I went from 2 starts and letting run until it died to 12 quick starts/off. Also tested continuity/ground of PCM and everything OK included voltage test of each ground and all came back well under one volt (per spec).

The 211 code requires at least 2 starts/runs before it's generated. So the multiple start/stop cycles helped it to return.

 

[jadams]

Call the guy at motoguy on the phone. He is friendly and helpful. Mabey he can point you in the right direction. (he might know someone that will test/rebuild your ECU)
Chris

Closed yesterday for 2 weeks for the holidays.

 

[budwich]

Hey man.... I think that you are getting somewhere... but where???

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". 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. 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. 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.

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