94 Explorer XLT 4wd. Loses power and stalls.

[RedDer]

Hello, first time here but have read many threads and hopefully I can get Mr. Shorty to weigh in. I will start with the codes and hopefully i got them right.
KOEO - 335
Memory - 157, 172, 176, 336
KOER - 172. 136, 336
Ok. I must admit this all started when i ran out of gas. I have since put premium gas in. Put Seafoam and Lucus in so pretty sure bad gas is eliminated. Replaced the PCV valve.
I have a limited income so I just do not want to throw parts in that is not needed. Although I did have to buy a new MAF sensor because the old one met its demise in the attempt of cleaning it. If it is absolutely necessary i can buy a fuel pressure gauge but I am leaning towaerd the DPFE sensor.
The main symtoms is kind of hard start followed by much pumping until the idle will get normal then it runs like a champ for about a mile then everything goes wrong. Rough idle, no power, can put it in nuetral and pump it till it get high rpm then will run good for about another mile and that is it. Basically limp it home and back to the drawing board with the help of mostly this forum. Thank you in advance for your input. I already know the obvious lesson to not run out of gas....

 

[MrQ]

I would say clogged fuel filter and/or bad fuel pump. Grab a $20 fuel pressure gauge from Harbor Freight and throw it on the test port. You should be at 30 psi or better.

BTW, premium gas makes no difference unless you are pinging. There is nothing better about 91/93 octane vs 87. Switching to a station with higher turnover in gas will help more. Fuel is fresher and has less of a chance of getting water and debris from the tank in it from sitting.

 

[RedDer]

That makes sense., forgot to mention that i did replace the fuel filter. I seemed to have wondered off the fuel system trail just because the pump sounds like it is doing the job and the symptoms i described are like clockwork. As if some kind of condition occurs that the computer does not like. Maybe temp., or i read somewhere that at start up the computer (is that the PCM?) Anyway, starts out one way then maintains fuel trim using just the o2 sensors and the MAF. I may be barking up the wrong tree but i have to believe it is a sensor/computer mis hap and not mechanical just because of how it does the same thing at the same time. Obviously it has the potential to run like it did because after i get it all primed up i can roll normal for that short time. If i do not roll and let it idle it does the same thing. All systems perfect then "blam" all systems not. Both are at the extremes....BTW much thanks for your response and you are right, i might have to spend that 20 on troubleshooting but would rather put it toward the solution.

 

[MrQ]

Unfortunately, most solutions are found by troubleshooting and eliminating possible issues and that costs money and time. Your O2 sensors are telling you that there is not enough fuel, ergo check the pressure.

When you are putting your foot in it, the fuel pump is forced to run longer, building up enough pressure in the system to support WOT and as that pressure drops when driving normally the engine starves, all indications of a weak fuel pump.

 

[roscoe 0202]

had a bronco II that the egr read low finally found bad fuel pumps no fuel no egr pressure
roscoe

 

[RedDer]

Ok..i will get a fuel pressure reading but if there is another theory as to why it decides to get weak at the same time every time. That does not sound like a mechanical problem to me but i suppose it could be weak and it takes that long to finally recognize etc...ok i will keep you updated. Thank you for your help. Please do not give up on me.

 

[RedDer]

Ok so i went to autozone to barrow the fuel pressure testing equipment. Not sure if i was doing it right because my readings are nowhere near what i expected. If you all can make sense of it then maybe i did it right. Here is what i got and how i got it. They gave me a brand new $150 test kit. Following the ford directions there was an adaptor that went on the Schrader valve (the one that looks like a tire valve) then the gauge to the adaptor. At first there was no pressure. Understandable since i released the pressure via that valve. I then energized tbe pump with the ignition and still nothing. Few more times still nothing. I should mention the directions stated that the procedure was to check pressure at an idle. So i started the engine being at the phase of rougb idle but still has rpm when pumped up. Anyway it had a bleeder valve on the gauge that i had to a gas gas can. I proceded to bleed it and noticed tbe rpm went up and was not so rough. Then i started to get a reading of btwn 10 and 14 psi. Only at an idle. No change when i hit the throttle. The only time it would get a reading was at idle. Hence the procedure instructions i guese. Now after giving this many attenpts to make sure of the readings and consistancy. Since it seemed to rimun better I took it for a drive. It sputtered a some but drove 90 percent better. Without pressing my luck i shut it down for the night. Today is the same symptoms however when i bleed the schrador valve it seems to start and run better for a short time .Also being under the hood today while it was running i noticed a cycling sound that got faster and faster and at a point of being for sure noticable and the engine at that point got worse until it was not going to stay started. I could not pin point if it was the egr assembly, the dpfe or the part that is past the throttle control. I am tired and just learning all this stuff. Anyway it was in the small area where the egr is. Also the round drum on the driver side fender, that is vacume related was making a noise i have not heard before. Well that is what i got. First of all is it possible i did the gas pressure test correct? Not sure why i got so many 0psi readings when there had to be pressure. Thank you in advance for your knowlege and willingness to share that with those who have no choice but to do it ourself.

 

[MrQ]

Glad you were able to check this. You have a weak fuel pump and it needs to be replaced. Reading is way low. 30 PSI minimum, 40+ when the fuel pressure regulator vacuum hose is disconnected. You would probably have to cycle the key a few times while not running before you got pressure at the rails, thus the 0 PSI.

Dropping the tank requires a long 16mm for the front two bolts on the gas tank, a short 13mm, 8mm, 7mm, assorted sizes of quick disconnect tools, long extension, wobble, jack and patience. A second pair of hands is always welcome with this job.

Remove the spare. Lift the explorer and put it on jack stands as high as it will go so the tank will slide out, (put them under the frame just before the forward leaf spring perches so the axle will drop a little bit making it easier to get to the two lines on the rear of the tank.)

Remove the two filler hoses going to the rear of the tank. Loosen the hose clamps and work them off.

Put your jack under the rear of the tank to support it. Towards the middle of the tank there will be a plastic strap. it has a long 13mm bolt that is over the top of the driveshaft bolted to the frame. Use the wobble and long extension to remove it (if you want you can unbolt the driveshaft from the rear axle to get more clearance. You will need a 12 point 12mm deep socket).

Drop the tank a little bit so as to reach the plastic evap line (DO NOT drop all the way, the plastic EVAP hose will break if stretched too far.) Remove the green evap line connector by squeezing the two tabs and pulling it off. Disconnect the electrical connector to the pump.

If you can reach the quick disconnects for the fuel lines remove them now, if you can't you can drop the tank a little more, just don't put any tension on the fuel lines. There will be a lot of fuel coming out of the lines so keeps some rags handy.

Lift the tank back up to its original position to take the strain off the two bolts on the front of the tank and remove them. Drop the tank again as far as it will go (you may have to slide it off the jack to get enough clearance) and slide backwards. (depending on how much fuel is in the tank a second pair of hands on the front of the tank may be required.)

Slide the tank off the jack once the front of the tank is on the ground if you haven't already. Move the tank to the passenger side to get it off the strap, then lift the strap out of the T-slot in the drivers side frame rail and slide it and the tank out from under the explorer.

Remove the 6 8mm screws holding the fuel pump sending unit in. Remember the orientation of the fuel lines! Carefully work the sending unit out of the tank, the fuel level float will not come out with some careful maneuvering so DON'T FORCE IT. Once out make sure the sock is still attached to the pump. If not, it's probably floating in the tank and you will need to fish it out.

Loosen the hose clamp holding the fuel line to the pump and remove the electrical connector from the pump. Use the 7mm socket to remove the bolt holding the pump retaining strap in place. Slide the pump out of the sending unit.

Install is the reverse of removal. Orient the sending unit as you took it out. Don't forget to install the evap line before lifting the tank all the way up. And push the tank up as far as it will go once done to get the strap bolted back in.

 

[MrQ]

Forgot to mention, it might be a good idea to remove the rear driver's side tire. You can get to the fuel lines a lot easier.

 

[RedDer]

What are your thoughts on cutting an access panel on the floor directly above the pump ? Wondering if that might be easier.

 

[MrQ]

I thoroughly discourage it. Cutting right above the fuel lines through the body is a really bad idea, not to mention a big risk. One spark after a fuel line is cut can be disastrous.

Doing it the right way may take longer, but is ultimately safer.

Also if you have to have quick access to replace fuel pumps all the time... then there is a much bigger problem.

 

[RedDer]

It is a fairly new pump and my problem started when i ran out of gas. I am just wondering if the sock or line is clogged or did it affect the fpr. I do not have the resources to drop the tank but if i have to then i will figure something out. Is there a way to blow out the lines via tha 3 lines that go to the tank?

 

[roscoe 0202]

new parts don't mean good parts that is why they come with a warranty
roscoe

 

[MrQ]

It is a fairly new pump and my problem started when i ran out of gas. I am just wondering if the sock or line is clogged or did it affect the fpr. I do not have the resources to drop the tank but if i have to then i will figure something out. Is there a way to blow out the lines via tha 3 lines that go to the tank?

If the sock is clogged the pump might have burned up...either way you are going to have to get into the tank.