Sorry mrshorty but I did what 87 mentioned even beat the tank with the wooden end of a hammer, still nothing. This is way I'm asking about the pump test.

The crappy Haynes manual that I have is supposed to cover from Explorers from 1991-1995 but the wiring schematics in the back only cover the 1991 and 1992.

Question: On my Explorer there is some sort of electrical box on the left frame-rail just forward of the fuel pressure regulator. All of the wiring from the fuel tank area feed up along the frame-rail and into this box, does anyone know what this is?

 

The vehicle repair guides at www.autozone.com have wiring diagrams (the same diagrams from Chilton's manuals). See if those are any better. That said, I don't think there's that much difference in the fuel pump circuit between a '92 and a '93.

When I get home, I'll have to look at my '92 to see what's going on along the frame rail. One note, the fuel pressure regulator isn't down there -- the FPR is on the forward end of the fuel rail on the engine. Are you looking at the fuel filter (a "cannister" in the fuel line)? As I recall, the "box" just forward of the filter on my '92 is the RABS module, which doesn't have anything to do with the fuel system. As I recall, the fuel pump wires go behind the RABS module (or into a wire loom) and on up into the engine compartment on their way to the ground and (in a round-about way) to the inertia switch. Is this a possibility?

 

Seems to me that where the fuel pump grounds & what the ECA uses for a ground to ground the fuel pump relay are 2 seperate things.

According to the wiring diagram for my 87 pin 60 of the ECA is connected to the engine ground & pin 22 is wired to the fuel pump relay. Apparently pin 60 & pin 22 are tied together with the key in run & this closes the fuel pump relay. I think your 542 indicates a similiar setup but where exactly is the ground on yours is the question.
A GOOD wiring diagram would sure be helpful for this. Like mrshorty sez check out the AZ site & see if you can find that ground point on the engine.
Look for an ECA to engine ground.

 

I should have thought of this sooner, but here is a VERY SIMPLE little test-courtesy of Rockledge- that you can do to see if the ECA is grounding the fuel pump relay.
Take a look at www.superhighoutput.com/tech_view.php?id=5. Use the negative post on the battery for your ground.

This test point is in the wire between the ECA & the fuel pump relay. Let us know if your pump comes on.

 

I'm done testing and the problem seems to be the fuel pump. I applied an alternate source of energy to the pump wiring and I didn't hear a thing.

Anyone ever pulled the fuel tank in a 93 Explorer?

How difficult is this job?

Are there any known problems that I should know about?

 

The fuel tank removal is quite a pain however the Haynes manual covers it pretty well

The problem here will be the rotted retainer ears if you live in a salty area. Visit your local junkyard and find a new tank with good ears and get a new retainer ring and gasket when you buy your replacement pump

 

The tank is just about out and it wasn't to bad of a job, 6 bolts is all there was. The worst part was trying to remove the filler pipe from the tank, not much room to get your hand up there to work it back.

The only thing left to do is disconnect the fuel lines from the pump and I can't do that until I get some tool from Ford tomorrow. Hopefully by this weekend this thing will be running again. Total time for the tank removal so far is about 45 minutes.

Actually 91, I was supprised when I dropped the skid plate, the tank in mine is not made of metal, some sort of hard plastic. As for the retainer ring, it did look pretty rotted so it will be replaced. Does anyone know if this is normal or did Ford factory install non-metal tanks in the 93 Explorer?

 

Rod,

The 91-94's use a plastic fuel tank. The retainer ring should be replaced but the key here is if the metal tabs which hold the ring have failed the tank must be replaced. I I live up nawth where the salt lives and I replaced the pump on mine this summer. Biggest problem was finding a new tank as they are not available from ford any longer

took me about 2 hours total time

 

94 Explorer, similar problem, Please help or direct. I have a problem where the fuel pump runs but never stops. Sometimes I can on/off the ignition switch and finally I will hear the pump click/or relay throw and then the engine will fire. When all I hear is the pump and there is no click/or relay throw, the Explorer will not start for anything. The Ford Dealer, my own mechanic, side walk supertendants are all baffeled. I have replaced the relay. there is fire at the plugs, 40 lbs or there about, fuel line pressure. Any thoughts? Once person suggested that the PCM may be bad. Once I hear the click of the relay and the pump shuts off, the engine starts right away and runs great. Then it will work okay for a few times but within a time of day it will not start. Any suggestions will be appreciated.

 

Sounds like your PCM is whacked or it's being told that the engine is running when it isnt.
I'm looking at the PCM wiring diagram for my 95 Taurus & my guess is that the cam sensor/CMP is what signals the PCM that the engine is running & to turn the pump on. Has anyone tried removing the connector to the CMP to see if the pump turns off?

Have any trouble codes been pulled & do you have a wiring diagram?

 

No they have not, to my knowledge. So in other words, when it won't click, or stop the pump, something, maybe the CMP, the PCM does not know that the gas is there?
Where is the CMP? I have been unable to get a wiring diagram for the 94 Explorer, so far. If I can find the CMP I can do what you suggest. I do appreciate your response.

 

The CMP is where the distributor used to be.
Like I said I'm only guessing at how this works.
Best bet would be to start a new thread on this.
I have the Ford wiring diagrams for my 2 Fords, but I think it's Mitchell that also has good wiring diagrams & you might find it at your library.

 

In closing.

After spending $114.89 plus tax at my local AutoZone for the complete pump assembly and another $10.95 plus tax at the local Mercury dealer for the pump mounting ring every thing seams fine, my 93 is running again.

I'm still not sure what the problem was with the old unit other than a short somewhere within the pump assembly because after I removed it from the tank and plugged it back into the harness I turned the key on and off 3 times. On the first 2 attempts the old pump kicked in as normal but on the 3rd attempt I got nothing so my "fuel open circuit" problem was within the fuel pump assembly itself.

Anyway, the installation of the pump went in easy, (just hoping that I got the ring mount tight enough) and the re-install of the tank and skid plate was easier then removing it.

Finally a little advice for anyone attempting this themselves, if you need the fuel line disconnect tool, do not get the tool from Advanced that is the diameter of a US .50 cent piece, it will not work. The output/return lines on the 93 Explorer are 3/8" and 5/16" not the "one size fits all" of the Advance tool so be sure to get the tool that works for the different size lines. This is not a knock of Advance because I do buy from them for other issues, (plus they do sell Chilton manuals).

In closing, I would like to thank all that offered advice on this project, my first electrical issue of which I hate and I hope everyone has a very Merry Christmas and a happy New Year.

Happy Holidays folks!