Engine quits...dealer can't help.

[LXJ31]

Its an intermittent problem, maybe someone has heard of this before. The engine on my '94 Explorer (6cyl) dies occasionally, much more often in hot weather. When the outside air temp is high, the engine will quit even at highway speeds. I have noticed when it quits at lights or other stops, it will kind of bog down, chugging slower and slower till its stalls and applying the gas pedal does no good. I thought it was vapor lock but the previous owner said she took it to the dealer and they couldn't get it to exhibit a problem so ops check ok, crazy lady.

I came to own this vehicle in a roundabout way, its owner going to Ireland for a temporary assignment and is now a permanent resident of the Emerald Isle. I rarely drive this vehicle and since I didn't "own" it till recently, have not put much time or effort into troubleshooting. This owner was just hoping that this was a recurring problem with a known fix. I hate having the neighborhoods biggest doorstop.

 

[SaleenEXP]

no clue, my 94' has had no problems at all.

 

[Bottomlesspit]

Boy...sounds like a tough one without more info.
I'll keep thinking about it...but you might just need to make sure all the tune-up stuff is in good working order. Air filter clean? PCV valve good? Spark plugs in good shape...properly gapped? Plug wires good and or replaced?
Another one that gave problems in my former stang world was the fuel filter. A lot of times all would seem well, but then power would start choking off. What happens is if you have enough sediment trapped in the fuel filter...while you drive is gets stirred up and slowly chokes off the line. Let the vehicle sit awhile and the sediment settles back down. Maybe a new fuel filter to be sure?
That's just a few things off the top of my head to check into. Keep providing info and maybe something will stand out.
Ken

 

[squd92expsp]

This sounds like a bad fuel pump to me. I drove a car that did exactly as you described it and that was the case. Hopefully it's not cause that can be expensive, but I would suggest having that looked at.

 

[LXJ31]

Thats a good point on the fuel pump and filter. Its the weirdest thing, the engine will die and if you try to restart immediately it will just gag, chug a little and die again. If you wait a few minutes, it will start strong and off you go. In cooler weather the wait time is much shorter.

I was supposed to sell this vehicle, but if I can get it reliably working again I may keep it. I'm pretty intrigued at all the tweaking that can be done to these trucks.

 

[Opera House]

Had this same problem on my 92

And no one could figure it out for a long time. There was a part I had suspected but it was considered so reliable that it wasn't a stocked item. Desperate, I ordered the fuel pressure regulator. After installing the new one, I cut open the old one to verify the cause of the problem. A flat hardened metal plate covered the valve orifice. The pressure spring on the plate was slightly off center. This caused a 30 degree bevel to be worn on the orifice surface. The vacuum is highest at idle and causes the plate to lift up more. Occasionally the plate will slide to the side on this bevel and stick. This held the valve open causing very low fuel pressure. When the engine would violently shake just before stopping, the plate would sometimes be reset to a normal position and everything would be fine for a while. You can tap on the pressure regulator and it will restart right away. Except when it sticks, the pressures are normal. Quite a few Explorer owners have had this problem. Aftermarket part is about $60 and is easy to change. Located on the passenger side of engine near the oil fill. Two bolts, vacuum line pushes on, and return gas line screws on. Should take 10 minutes. Disconnect battery for 15 minutes to reset the computer, this is a must do!

Just last week, this worked on an Explorer that a guy had spent hundreds of dollars on and had been to several mechanics.

 

[LXJ31]

Sounds promising, thank you! I'm getting on it today and I will let you know the outcome.

Added at 0115z:

I got another tidbit of advice today regarding this problem: replace the fuel pump relay right behind the battery. I did that a couple of hours ago, drove it around and let it idle in the driveway for about twenty minutes and no problems. Its early yet but I'm pretty hopeful. I'll drive it to the airport and back tommorow just like a did a few days ago (it died right at the curb where they tell you not to park) and see if it has any problems. I will keep you posted.

 

[Opera House]

If you have a DVM

The fuel pump fuse can be removed and there are many flat electrical connectors that will fit into the fuse clips. I like the U type screw connectors with one of the tangs cut off. This will fit the mini through the maxi fuse holders. I crimp these to a length of lamp cord so I can monitor current in the cab while I drive. Good connections are important because you don't want to loose power on the highway. Do a current check at idle, write it down. This will be the low current value that represents the lowest fuel pressure at the highest vacuum. Then remove the vacuum hose to the regulator. This will be the high current value when you are accelerating or under load. The vacuum effect on the regulator acts much the same as the old accelerator pump. Giving that extra boost of gas till the engine controls can trim the mixture. The pump current should be about 5A. The first 5 minutes of engine running the current will be a little higher till the pump warms up and the resistance of the windings increases. Keep that in mind when you make your readings. From the highest current, current usually drop more than a 0.5A. Below 4A, you are usually getting in trouble. Engine will quit at about 2A. Pump current is a good diagnostic because in this system, 80% of the fuel goes back to the tank. This serves to cool the fuel rail and pump. As a result, current is a good indicator of pressure. It is a lot easier to deal with than a pressure gauge and hose hanging out of the hood. As the gears in the pump wear, the pump current also drops. Also interesting is that the voltage at the pump can drop to almost half and the vehicle will still run. This explains why bad contacts in relays and connectors lead to illusive problems.

 

[Tango40]

My wifes sebring had the same problem about 2-3 months ago took it to the dealler could not replicate the problem,my buddy said his girl had same problem he said a tow truck driver went to tow her car and thought it was a short in the fuel pump,his solution sounds kind of crazy,was to take a 2x4 and hit the gas tank a couple times,she hasnt had any trouble since,i tried it on my wifes car and she has not had any trouble yet eaither.something to try.good luck.

 

[oceanworker]

Start with the easiest (cheapest) fix. If you say the truck has sat around and not driven for a while, you could have water in the gas tank from condensation. This would happen especially if the gas cap wasn't on tight and the tank had 1/4 or less in it during storage. Dump in a can of "dry gas".

 

[LXJ31]

Well all, it seems to be fixed. I started with the ultimate in easy fixes, the fuel pump relay and I haven't had any problems for three days. The problem would have shown up by now, based on past experience. Now to change all the fluids and flush the radiator...

Thanks for the help and insight.

 

[daniel cauchon]

I must admit Opera House you realy amazed me..I would like to know just 10% of what you know..you realy are a great connaisseurs.. realy. Everything you say is so descriptives ,! it alomos seems like you made the Ex..thank s to guys like you, guys like me learn alot.