2001 Ford Windstar stalls randomly under acceleration

[JHaus]

I have a 2001 Ford Windstar SE. 220,000 miles. A few months back it started missing ... I drove it like that just local for a few days but then I was leaving town for about a month and just parked it. After I got back I changed the plugs and all was fine on the test drive (ran perfect ... fixed the misfire). What has happened since then has been frustrating. Althought it runs great, now it stalls randomly and always when it's under acceleration and usually going up slight or a bit steeper hills (think So Cal terrain). It doesn't jerk or miss or sputter ... it just cuts out. If you try to turn the engine over without turning the key off it won't start. Turn off the key then turn it on and it starts like nothing ever happened. No codes whatsoever. Sometimes you can drive it for 30 to 50 miles or more and have no problems at all, then all of a sudden it will stall in an area that it had no problems with over the previous week or so. It seems to stall out at about the time it wants to shift from 1st to 2nd or from 2nd to 3rd ... or at least that general rpm or accelerator pedal position. It's happened with light acceleration and heavy (pulling a long hill) acceleration. Never at idle or decelerating or just cruising on a flat piece of roadway ... never. It also seems the pedal needs to be at a constant position (not pushing down or letting up but just at a certain position under acceleration). I've had my mechanic with me 3 different times and each time it never stalled with him along. Fuel pressure was fine when he checked it (while driving). Once in a while it will cut out (just enough to notice) then cut right back in and keep running but most of the time it just cuts out and that's it. I've changed the camshaft sensor, the crankshaft sensor, the PCM relay, the fuel pump relay, the throttle position sensor and the fuel filter. I'm hoping to set it up next week where if it stalls I can call the mechanic and have him come over to where I am and see if a code comes up (and check the fuel pressure also) without me turning it off (since that seems to reset whatever the problems is). I'm frustrated and any advice would be greatly appreciated. I've read other forums (including threads here) with similar problems but never read what the answer to this problem is/was. Thanks for your time.

[12Ounce]

Does your engine have the coil pack or the coil-on-plug setup?

[scubacat]

12ounce beat me to it yet again.

Check the coil pack. Remove it and look at the bottom. If you see even a tiny crack, that's your problem. Replace it and you're good to go. It could also be a bad fuel pump, though, like you seem to already suspect. They do sometimes act sporadically on their way out. The tester may be available for rent from autozone, or if not, it shouldn't cost too much to buy one.

http://www.harborfreight.com/fuel-in...ter-92699.html

[12Ounce]

IF your engine uses the coil pack, you should be on about your fourth, or so, it has been my experience. Our 1999 has over 400 kmiles ... and it probably has its fifth coil in it. They just don't last forever with the heat and other harsh engine-box conditions going on. BUT ..... along with the coil pack, the spark cables need to be replaced ... and "dressed" so that they are separated from engine "ground" and secured so that vibrations will not lead to early failure.

[JHaus]

Hey All,
Thanks so much for your input. The parts I talked about replacing in my original post are parts I've replaced since the stalling problem started. More parts history include the coil pack being replaced inside of 2 years (probably has about 25K on it). The plug wires were replaced about a year ago (probably about 15K on those). The plugs probably have less than 1000k on them. I also replaced the Mass airflow sensor about 3 years ago. Could the fouling plug (I think it was just one that was causing the misfire) that I talked about at the beginning of my original post have damaged the coil pack in any way ?? That's the only way I can think that the coil pack would be damaged again since it's not too old. Also would you have to turn the key 'off' before it would restart if it was the coil pack ?? If you try to restart it without turning the key off it just turns over (no sputtering or anything ... just turns over without starting). This makes me think that something (sensor or such) is resetting when I turn the key off. It's also curious because it always does it right about the time/rpm that it reaches to shift from 1st to 2nd or 2nd to 3rd. One other thing ... at the same time this stalling problem happened it also started shifting with more of a 'tunk' between 1st and 2nd. Especially at low speeds and with very little gas pedal ... for instance when going thru a parking lot or such. I also wonder about the unburnt fuel from the fouled plug causing damage to the oxygen sensors but I don't really know much about that. I probably drove it around 30 miles or so with the fouled plug on it. Outside of this stalling problem every once in a great while the van is running very well. Thanks again for all your help.

[12Ounce]

You know the coil pack fires the plugs in pairs ... so if you have one plug that is fouling, you could swap the cables between the two sibling plugs to see if the sister plug begins fouling.
.
Yes, the engine starts in some sort of default firing order that lasts just a few seconds ... until it sees a complete revolution sensed by the crank sensor ... could it be that this sensor has a problem? Loose wiring perhaps?

[JHaus]

Thanks 12 Once and Scuba Cat for your reply's ...
A fouling plug was the original problem I had. I changed all the plugs and it fixed the miss I had in the engine. Drove it and I was so happy because the van was running as well as it ever had ... when all of a sudden one day it just cut out (stalled) on me (probably about 30 miles or so after the plug changing). This had never happened before. The crank sensor was one of the first things I replaced thinking that this might of been the problem. But unfortunately it wasn't. One question I have. Next time it stalls (it can go up to 50 miles plus in all kinds of conditions without having any problem whatsoever by the way) ... if I hook a code reader (with live data readings) should that give me some sort of clue to the problem ?? (outside of fuel pressure since there is no reading/sensor for that outside of hooking up a gauge to the fuel rail). I'm just thinking of getting a fuel pressure gauge and the code reader (with live data feed) hoping to figure out the problem before I turn off the key to restart the engine (since doing this always resets and fixes whatever caused the stalling). It would be a bit of a investment but I would have those two items to use from that point forward and would be able to help others out also. Like I said it always happens under load (acceleration) and usually right around the shift rpm between 1st and 2nd gear and 2nd and 3rd gear .. always ... no exceptions. Outside of this mysterious stall problem which happens once in a blue moon, the van runs perfect. Thanks again guys.

[12Ounce]

OK, now I think I am back to understanding the current symptoms ... a sudden and complete shutdown, with no warnings or precursors, and it only happens under acceleration or other heavy engine loading. Yes?
.
If this is correct, I'm going with some sort of electrical problem that is aggravated when the engine twists, under load, in the engine sub frame or engine/tranny supports. You would not be the first to have a harness that has a conductor that may be opened, or go to ground, when this happens.

[12Ounce]

BTW, our Winnie ... early in its life ... had unpredictable bouts of engine lurching and tranny down/up shifting ... so bad the car would nearly come to a stop, bucking about. The dealer tried, but could find nothing. One night it was so bad, I decided if I ever made it back home the car would not leave the driveway until the problem was found. I began stripping everything out of the engine box. When the main power train harness was removed, the one to the PCM, there the three rubbed away wire-covers were found. Its an infrequent problem it seems ... but it happens. Harness had rubbed against firewall.

[JHaus]

Hey Guys ... I think we are getting to the end of this problem. Had the mechanic come over last week. We did a indepth check of the engine and tranny mounts as far as twisting under load and such. Everything was fine. So we decided to go for a ride and guess what ?? ... it finally stalled out with the mechanic with me. We pulled into a drive off the main road. First thing we did was check the fuel pressure. Nothing. So he hooked up his code reader (has a nice one with everything you can think of). No codes and everything seemed to be reading fine when he turned the engine over (still wouldn't start since we didn't cycle the key which is to say turn it off and back on). Well then we noticed the fuel pressure was back to normal but still wouldn't start. Obviously no spark. We checked a few other things ... all was fine so we cycled the key and it started right up like always. He came to the conclusion it was probably a voltage spike that is killing the engine (messing up the computer). He used to be a ford tech but never had seen this and he figured either alternator or coil pack could be causing the problem. I've unhooked the alternator (and only hook it back up to charge the battery or to drive at night) and I haven't had one issue in a week with the alternator unhooked. At this point it really looks like the alternator is the problem. Will give it a few more days and lot more hills to test this theory. and let you know how it goes. He mentioned also that driving it for so long with a misfiring plug may have led up to this since it stared stalling after I changed out the bad plug(s). He said he has seen electrical components (especially coil packs) get damaged from misfires but they don't show it externally .. only damage is inside the pack. How does this sound to you?? Thanks again for all.

[scubacat]

Thanks for the update and congrats on finding the problem! The voltage regulator is indeed built in to the alternator on Windstars so it looks like the mystery is solved. Nice work!

[tomj76]

> Obviously no spark.

I agree that the data strongly suggests, but did he confirm by checking for spark? Seeing is believing.

After that I'd check the inputs to the coil pack, to make sure that it gets good data from the PCM. Maybe try unplugging the power to the coil pack to see if that is equivalent to the key-off, or pull a fuse to the PCM.

Also if the alternator is a fault, I'd guess an oscilloscope of the output should show a noisy output. Finally, keep in mind that a well connected battery should resist a voltage spike from the alternator.

[JHaus]

Hey everyone,
So after unhooking the alternator and driving around and not having the problem I assumed it was the alternator. I was able to 'borrow' an alternator I knew was good to check it out. When I hooked the new alternator up it still had the stall problem. My next target was the coil pack. It tested out ok but the mechanic told me that it could still be the problem. His thought was that at 12 1/2 volts (without the alternator hooked up) it could handle the current but when the alternator was hooked up and 14 1/2 volts were running thru the system then at high rpm (it always stalled out at high rpms right around the time it would shift from 1st to 2nd or 2nd to 3rd) it would randomly spike. That had to be the problem because I installed a new coil pack a couple weeks ago and haven't had a problem since. Testing the old coil pack (was 1 1/2 yrs old) shows its ok but for whatever reason at high rpm and with the extra volts the alternator supplies the system the coil pack randomly failed every once in great while (sometimes I could go 40 miles or so without a fail). So glad to have this problem behind me. Have a few other odds and ends to take care of and will be going thru some of these windstar threads to see what others did to solve them. Thank you all for your responses.

[scubacat]

Curious - did you look at the back of the old coil pack? There's probably a tiny hairline crack that caused all your issues. Those coil packs are definitely a weak point in these vans. Fortunately anything newer use coil-on-plug which eliminates the need to service the pack and wires (and eliminates the wasted spark as well). I always check that coil pack these days due to how many times it's burned us all.

Congrats on the fix!

[12Ounce]

Originally Posted by 12Ounce

IF your engine uses the coil pack, you should be on about your fourth, or so, it has been my experience. Our 1999 has over 400 kmiles ... and it probably has its fifth coil in it. They just don't last forever with the heat and other harsh engine-box conditions going on. BUT ..... along with the coil pack, the spark cables need to be replaced ... and "dressed" so that they are separated from engine "ground" and secured so that vibrations will not lead to early failure.

.
Ahem!
.
Glad you found your problem. Those packs can be tricky!