Ex Dies/stalls Without Warning

[shifty1]

Hello all, I need help!! My truck needs help too!!

I have asked this question before, but the problem is getting much worse. Here is whats happening.

The truck will stall without any warning whatsoever. It doesn't matter whether during accelleration or decelleration.
For the last 7 months it would happen once or twice then go a few weeks to a month or so without happening again. As of this weekend it was happening every 30 sec to 5 minutes.
There is no sputter or surge, I'll just be driving, look down at the guages and see 0 rpm, then the CEL and battery light come on and bye bye power steering. (I'm not showing any codes).
I can sometimes put it in neutral, turn off the key and get it to start before coming to a stop.
Most of the time, it will come to a stop, I put it in park and it will take from 1-5 minutes for it to start up again.

Last week it was turning over, but would not start at all, put it in the garage and they found a (supposedly anyways) bad wire at the PCM Relay. After changing that, it was fine for a week (as I said before it is not uncommon for it to go a week or more between occurances).
This weekend my pregnant wife and I were headed out of town and it started again, only very frequently this time.

One thing I did notice and I'm not sure if it means anything, but it has never stalled when I'm on Cruise Control?? It stalled twice in a 1/2 km (canada) stretch, got it going on the hwy rode the cruise and didn't stall the rest of the way home (250km's).

I have previously switched the fuel relay w/ another, cleaned MAF and IAC, changed plugs and Fuel Filter.

I do not think that this is a fuel problem due to the intermittentness (new word), and there is no sputtering.

Any chance that this would be an ignition component (would this not happen if spark was lost?) What would be the best way for a driveway wannabee mechanic to test for a problem here, or is it possible?

PCM?? If the mechanic found a fault w/ the power to the PCM relay, could it have actually been the power in the PCM that was failing??
I am leaning towards the computer, but it would be a pretty expensive mistake.

Maybe a bad ground somewhere?

BTW, my stereo and lights whatnot DO NOT fail so it doesnt make me think that I am losing "power". Just the engine.

Sorry about the long post, its just that I want to get everything figured out, especially considering my 8 month pregnant wife drives my truck now more often than not (at least until this weekend she did).

 

[liqhx2]

when it dies your able to still crank the motor right? if you are does the exuaghst smell like it's flooded out or not? if you can still smell gas out of the tail pipe and it is not starting then it's probobly a spark problem could be a bad coil pack if your coil pack is loose from the bracket then it will not be able to ground properly. but i have had a funky fuel pump before do what your saying your truck is doing it woudl go fine for a while then just die then go again then die without warning otherwise it could be a short somwhere that when bumped just right cut's the motor.

 

[shifty1]

Yes the motor does turn over, it just wont start. At that point I would think fuel system, I'm just concerned with the way it stalls.
Would the fuel pump just cut out intermittently like that??

When I had the wire at the PCM replaced last week, it wouldn't start at all over at least a few hours time (I tried it once that night while in the Garages parking lot). It started after that. So I was/am leaning that way, but who knows, it probably started for them but nothing pays like job creation!!
Funny story with that. My truck has an anti theft that makes is so you have to hit the unlock button on the keyless before ot will turn over. The garage calls me and says that they found the problem, it had power to the ignition but no power to the starter. So they had to change that and then told me that it was already 2 hours labour to find that "electrical problem". I told them that I was there the night before and it turned over fine. He tells me that his mechanic was able to do the same the night before as well. After I inform him about the anti theft he says "oh, well you'll still have to pay that because I didn't tell the mechanic..... How did his guy turn it over the night before???? Didn't have to pay for that.

Anyways, maybe it is the fuel pump and its just getting worse? I'll have to check out that post on mounting a pressure gauge in the cab.
Can someone please tell me exactly where the fuel pressure regulator is, I am aware that this is possibly the problem (thanks Opera House) and would like to know where to find it!!

Thanks in advance

Shifty1

 

[liqhx2]

when you lookin at the motor you can see the top radiator hose look right behind that and you'll see it it'll have a braded cable coming into the top of it and two bolts that bolt it into the fuel rail and a small vacum line running into the back side of it it's not very big but pull off the vacum line and see if fuel is spitting out there if it is that means a bad fpr and get a fuel pressure guage on it and that will help diagnose that if it is that but i have had a fuel pump do this to me before and i was thinkiing electrical to but then i decided when it happend again i srayed a little starting fluid into the intake and it tried to start so that showed me it was actaually a fuel problem so i changed the fuel filter worked a while then did the same thing again changed the fuel pump never had another problem with it

 

[shifty1]

Thanks again, I'll look at it when I get home.

 

[Purdue72]

Have you checked your fuel pump relay? Mine did exactly what you are describing last summer. It would stall at red lights or at 80mph. Turns out my relay was sticking. $30 relay fixed it.

 

[shifty1]

I have switched the relays, and it didn't solve anything. I just swapped it with one of the identical ones. Unless they are both fried?

 

[Purdue72]

actually, now that you say that, I remember replacing the "power" relay as well.

 

[shifty1]

Update: While it was happening again last night I was able to diagnose that the fuel pump was not priming each time that it would not start, and then as soon as it did prime, it started. So I am pretty sure that the fuel pump is to blame.
My mechanic buddy told me that he thought that Ford had a system where the fuel pump would not power up as long as there is no spark. Is this true?? If so, then I guess I'm pretty much back at square one.
The next time it stalls, I plan on spraying carb cleaner into the intake to see if it starts.
Either that or pulling a wire and manually checking for a spark.

If there is spark, then would I be safe to assume that it is in fact the pump?

btw- I rotated a few of the relays again, and each of them "clicks" when it turns over, so I'm pretty sure its not that.

Please let me know if there is anything else I may do to diagnose.
I don't want to just start changing parts (ie fuel pump) w/o knowing what it is. I just bought my first house and take possession in 2 days.... I can't afford to just start guessing.

Thanks again in advance for any help/suggestions.

Rob

 

[TPLYNCH]

Your buddy is wrong. When you turn your key to "on", stop and don't turn key all the way to Start. You should hear the FP whine - priming. If you don't hear the whine, then the FP is not running. If this happens, one way to verify whether or not it may be the relay is to leave the key in the "on" position, go to the relay box under the hood, and jiggle the relay. If when your jiggling you hear the FP whine, then its more than likely the relay, or the little connectors in the relay box may be dirty. There was an incidence once related on this board where I believe the bottom of the relay box would move and the connection lost, leading to FP cutoff. If relay checks out, then it could be the wiring to the FP- can check w/a voltmeter to see if juice making it to the gas tank, and last resort if wiring checks out, replacing the FP itself.

 

[shifty1]

Is there an easy way to check the power to the pump? Or do I have to drop the tank? Specifically, is there any way to unplug the electrical connector from the pump w/o removing the gas tank?

Checking the various components is tough, I can only try things when the truck is actually stalling.
Can someone please verify again that a bad fuel pump can act this way (intermittant stalling, and then re starting again shortly after) If it were the pump would it not just stop working all together? If or when I drop the tank I'll check the connections for corrosion, hopefully that is the issue.

 

[mabulok]

You can check for power to the pump: remove the fuel pump relay and check for voltage at one of the terminals with the ignition key off. One terminal should be hot. Then cycle the ignition key on/off (not start) and check the remaining terminals for voltage. There should be voltage for 2-3 seconds at one of these. It will stop after 2-3 seconds because the fuel pump automatically shuts off if the engine isn't sending timing pulses. Some other things to check would be voltage at the fuel pump, ground continuity, and finally listen for the fuel pump when it's first switched on, should run for 2-3 seconds before it shuts of because of a lack of engine timing pulses. If you have voltage at the pump and it still won't run, replace it.

 

[shifty1]

Apparently my buddy was right!! No spark, no fuel pump.

I was replying to similar threads and it occured to me that I should give a final update on my thread in hopes that it helps someone.

my '94 got to the point where I couldn't go more than a km without stalling. The main problem I was having with diagnosing it was that I could never tell if it started because of something I did, or on its own. Sometimes it would start again before I came to a stop, sometimes it would take 20 minutes.
Anyways, last thursday I was ready to give up and change the FP becuase it seemed the most likely (wasn't priming/whining whenever it wouldnt start, and was priming when it would start).
It was stalled long enough for me to pull a wire and check for spark which wasn't there as long as it wouldnt start, but did happen when it would start.
Turns out that the problem was a bad contact on the EEC relay. I could manually make it stall when I tapped it, or slightly twisted it and it would start when I played with it while wifey turned it over.
One of the prongs was twisted, which I cannot see how this could have possibly happened. It looked as though somone put a pair of pliers on it and twisted it. I cant see how only one of them twisted, I couldnt twist only one of them when I tried to. Almost looks as though someone may have done it knowing it would cause a costly hard to diagnose electrical problem. Probably not, but maybe.

Thanks to everyone for their help, this site has been a great help to me.

Rob

 

[hisnhersxlt]

I have exactly the same problem going on with my '94 Explorer XLT right now. I have had it in the shop multiple times, and no one can seem to fix it. Coulp you please tell me what an 'EEC relay' is, and how I can go about fixing it?
Any help would be greatly appreciated!