Engine Slowly Loses Power and Dies While Driving

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  #1  
Old 01-07-07, 12:11 PM
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Engine Slowly Loses Power and Dies While Driving

1999 Ford Windstar Cargo Van 3.8 Auto w/ 142K

Van died on highway w/no warning lights
Slowly lost power until engine shut off
Attempted re-start
Hard starts (stumbling) and dies until finally one of them “took” and van idles smooth
Was able to get ¼ mile until engine dies again
Did this numerous times
Same deal until at one point it seemed to run fine and I babied it to my destination
It had seemed the problem went away

Next morning, after checking for vac. leaks, etc., and a short drive with no problems, it did it again
After a few hard starts, it ran well enough to get to a service station

They found no codes, they found no vac leaks, or electrical problems, but the fuel pressure was “lower than it should be”
They replaced a rusty fuel filter and were confident that was the culprit

I was able to drive a few states back to my home with no problems
Well, close
It did it again a few miles from home
I let it sit a while, and was able to restart and slowly got up to speed on the highway and get the last 15 miles or so w/o problems
But this time it lit up the MIL so now back home I did my own tests

I retrieved a PO171 code (bank 1 reading lean)
That is the only code

I was able to duplicate the problem by running the engine up to 4K and holding it
While monitoring the Short Term Fuel Trim during the duplication, at 4K when the engine would stumble, the STFT would bounce down to around -20% (bouncing up and down extremely rapidly between 0 and -20%)

The fuel pressure test:
KOEO should be (as per AllData) 240-310 kPa
I’ve got 280kPa
KOER should be 210 - 310 kPa
I’ve got 220 at idle
200 at 3K RPM
At 4K RPM it seems up to 220 kPa, but when the stumbling starts, the pressure slowly drops, along with the RPMs, until both are 0 and the engine dies
After dying the FP goes back up to 240 and stays there, for quite a long time after the key is removed
It immediately goes back up to 280 if the key is put back to the “On” position

It seems to me to be a fuel delivery problem, but usually (in my experience) when the fuel pump goes, it dies
There’s no intermittent or RPM related problems

Any tips, tricks, suggestions, or solutions would be appreciated
Thank You
 
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  #2  
Old 01-07-07, 01:05 PM
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Sounds like a MAF sensor. Try getting some cleaner and see if that works. If not, try a new MAF.
 
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Old 01-07-07, 03:45 PM
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Thanks for the reply
The MAF is clean as a whistle
 
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Old 01-07-07, 04:13 PM
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Could still be the pump going. On my truck they die in one of two modes: Dead-dead-dead or intermittently the engine will just die, usually sitting at a traffic light. The fuel filter change making an improvement makes me tend to agree with you on fuel delivery.
 
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Old 01-07-07, 06:09 PM
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Hmmm....well I appreciate the confirm that they can go intermittently, T_G

Being able to reproduce the problem @ 4K RPMs has only happened after the shop looked at it, and replaced the filter...and I drove it 200 miles w/o a sputter
Before, it could only be described as intermittent

The pump replacement requires a tank drop and a $200+ pump
I'll look for a pump test that I can do with it still in place before considering that
 
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Old 01-07-07, 06:34 PM
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Still thinkin fuel pump..........You need to do a volumn as well as pressure test. Should pump out a pint in 15 sec of crank.............to really test it, pressure wise, you need to get it into failure mode and test it at that point.........May mean a "roadside" diagnosis
 
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Old 01-07-07, 11:06 PM
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look at relay too

the pump relay could be on its way out too.

Diminished pump volume effects will be seen at high load/speed, since most pumped gas is returned to the tank.
 
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Old 01-07-07, 11:41 PM
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would expect the pump also, have seen vehicles towed several times for an intermitant fuel pump problem before a shop would be able to get it to act up for them to make a diagnosis.
 
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Old 01-08-07, 07:08 AM
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Thanks for the replies

Now it only stumbles when it reaches 4K RPM, but switching the relay (with the horn relay) had no effect on that, it still stumbled @ 4K RPM

I started it up with the fuel pressure gauge pressure release valve opened and draining into a mason jar
After 15 sec. of run time (it still started up and ran) I got 3 oz. of fuel
-not sure if that helps, obviously not all the fuel pumped made it into the mason jar if the engine could still run for 15 seconds

(alldata says fuel flow should be 21 lbs. per hour....)
 

Last edited by slickshift; 01-08-07 at 07:11 AM. Reason: added spec
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Old 01-08-07, 09:21 AM
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dies

try taping a fule pressure gage to the windshield and drive you will prob see pressure droping slowly and pressure can be fine but pump might not deliver enuff valume well i guess i should of read all of the post you got it lol
 
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Old 01-08-07, 01:15 PM
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Huh....hey I got a question
So I decided to change out the pump
I dropped the tank and pulled out the pump housing
I opened 'er up to switch out the actual pump itself
Found something I don't remember seeing last time I switched out a fuel pump

Now here's my Q:
What's all this white crystal stuff loaded up the the inside of this housing?
Looks like sugar?

< grumble smilie >

It can't be......can it?
 
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Old 01-08-07, 03:11 PM
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Oh man
That stuff is in the gas tank too

I can't really see in there too far, but on one of the ridges near the opening I found some

Can I clean this out somehow?
The way it's shaped I'll never be able to dump it out or shake it out
It's just not gonna happen

Unhook it the rest of the way and take it to a pro?
Get a new tank?

Powerwash this baby out in the back yard to dissolve the sugar?
 
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Old 01-08-07, 04:48 PM
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It's amazing. I was going to post something a day ago stating somebody you didnt like put something in your gas tank. I was going to say trash bag, but I've heard sugar would clog a pump and make it a intermitant problem.

Also, the gas stations tanks can have alot of debris in them and that will be transfered to your tank. Usually this depris is something other then white crystals which sounds like sugar.

The question is now, who did you piss off?


I would recommend a complete fuel line and injection cleaning now.
 
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Old 01-08-07, 04:50 PM
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Originally Posted by slickshift View Post
Powerwash this baby out in the back yard to dissolve the sugar?
That's what I'd do. If need be make an angle fitting for your pressure washer. Once you are sure you've got it clean, rinse it with some gas or paint thinner. You might try blowing out what you can with an air gun. Use a couple bottles of dry gas when you reinstall and put gas in it
 
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Old 01-08-07, 06:00 PM
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Hmmm, could be sugar I suppose; the mythbust on sugar in a gas tank is that it will not dissolve. Not sure I would worry about the lines and injectors; if it can't dissolve it should all be caught in the sock on the pump or in the filter.
 
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Old 01-08-07, 06:59 PM
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I saved some of the stuff and dried it out
It's white-looks just like sugar
Then I donned my safety glasses and mixed some warm water with it

It dissolved immediately

I'm going to assume I got sugared, and water would dissolve what left in the tank
It'll be a bit of a pain, as the shape of the tank and the placement and inset of the opening won't let me pour out the old gas still in there, or the sugar, or any cleaning or rinsing fluids, but....
I don't see any other way to get this back on the road anytime soon in an economical manner

I'll PU a (-nother) new filter and some dry gas tomorrow AM

I suppose I should still install the new pump, as with all this labor it doesn't make sense to install a potentially (at least partially) burned out one

Can't imagine who I POed
Lol
I really am a nice guy
 
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Old 01-08-07, 07:19 PM
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Also install a locking gas cap.
 
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Old 01-08-07, 07:24 PM
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Oooh...yeah
Thanks
Add to list:
1. Locking Gas Cap
 
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Old 01-08-07, 09:38 PM
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Yea, I have the same car with 150,000 miles and had a P0171 and P0174 code.
Fixed the codes by replacing the vacuum elbow on top of the intake plenum.
The rubber elbows deteriorate. Look closely at it. I missed it the first time.
I didn't have the dieing out problem but you may have gotten a really dirty tank of gas and may need to replace the filter again. Also look for a second fuel filter. Some of these cars have two filters.
 
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Old 01-10-07, 05:35 AM
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Well, the tank was mostly off anyway, to gain access to the top
So I removed it the rest of the way
Which was a bit of a task, as it still had almost 10 gal. of fuel in it

I slid it out on a creeper as far as I could (small garage-not much room), then tilted and dragged it to a hand truck, and took it around back

Set it on some milk crates (for height), and drained and siphoned most of the fuel into a container
Eventually using a small hand pump for the last bits

I scraped out what I could, with the small hand pump getting a fair amount of it

I then took a bucket of hot water and poured it in there
I swished it around as well as I could-which was pretty funny as this tank is pretty big, I'm sure it looked like I was dancing with this thing

I then hand pumped that mixture out, and didn't find any grains when pumping
I wiped out what I could and let it dry a bit

I then dumped some fresh gas in, swished that around, and hand pumped that out
Wiped what I could of the inside and let that dry for a bit

I couldn't find any grains even by reaching in and feeling around, so I figured that was as good as it gets, and re-installed it

I put a bottle of drygas in, then some gas, tested for leaks-couldn't get pressure, another bottle of drygas, and then some more gasoline
Eventually I dropped the rear off the jack stands, got it to run and had good solid pressure

I still get a stumble @ 4K....maybe that is a Rev Limiter
Either that or I didn't fix the original problem (or it's a different problem)
As it was intermittent, I guess we won't know for a few days
(Oh yeah, new filter and locking gas cap too)
Thanks for all the help
Wish me luck!
 
  #21  
Old 01-10-07, 07:26 AM
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Originally Posted by slickshift View Post
pretty funny as this tank is pretty big, I'm sure it looked like I was dancing with this thing
who was leading?

hope all that work solved the problem.
 
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Old 01-15-07, 07:43 AM
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Update

Originally Posted by marksr View Post
...who was leading?
I'm not sure
I was giving it my best shot
But the whisper in the gas tank's ear to " let me lead" had about the same effect it does on my wife (works till the chorus come around again)


400+ miles and (knock on wood) no problems!
Thanks All!
 
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