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Reading voltage on inertia switch

the pump will not prime, the pump will run as long as you have the wire hooked up.

Are we sure it is a + signal that is sent through the inertia switch people?

I would have to check but I think I remember the computer output to the fuel pump is a - signal??
Sorry for the confusion......
 



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Yes "we" are sure.... the motor has a ground on one side and the only way to get it to run is to get it 12v on the other. As for color, sorry can't help you as my 96 diagram wiring color is different..... it DOESN'T really matter, if you aren't sure..... try any and all connector contacts at the switch since putting 12 volts on the side going toward 12volt (ie. battery side of the switch) isn't going to do anything.


Added: from the diagram post in this long thread and from my chilton, it would appear that you want to be on the PK/BK on the connector at the inertia switch. but as I indicated try them all, it won't hurt anything. Use your test light to make sure you are seeing a voltage being sent into the wire.
 






Its pouring here but as soon as it stops I will give it a go! Thanks again!
 






The fuel pump connector is attached to the side of the frame, the inner side, inside channel, behind the tank, where the frame goes upward to the rear end. It's above and slightly forward of the rear end.
 






To recap:
1. TCHD has inserted a jumper at the inertia switch
2. She has put a test light on the jumper
3. The light indicates a +12 volt signal for 1-2 seconds
Ergo:
1. Wire(s) good from EEC to relay to inertia switch
2. Wire to pump, connector and pump itself is unknown

Most likely problem
1. Pump
2. Pump Connections
3. Wiring to pump

Recommended course of action:
Unless there is skill and access to a time domain reflectometer, troubleshooting all 3 requires access to pump. As long as tank is down; change the pump. The float will go bad next year anyway.
 






Finally the conclusion to this very long thread! i was able to attach the wires directly from battery to inertia switch with no results. with help I was able to replace fuel pump but the skid plate is now scrap metal. I wont be offroading anyway. After replacing the pump she fired right up!! Yayh....not so fast. after running for about 10 minutes I turned it off and now my starter has taken a poop! But I dont think I will need to start a thread for this repair....at least I hope not. Thanks to all who helped and for hanging in all the way to the end of this thread.
 






Glad to hear your fuel problem is solved...Unfortunately in many cases the problem is known from the start, but you need to drill down and eliminate all possibilities before biting the bullet and replacing a $$$ part...
 






I have been watching this with nothing to add until now
None of the women in my life would have given this much effort, even faced with necessity. You are to be commended !:thumbsup:
 






Thank you for your encouragement and comments. I love my explorer, but I love my kids more and this vehicle is our livelihood. Without it we would not survive. I cannot afford to have someone else do it so I must rely on myself and alot of help from great mechanics on this sight. being a girl sometimes makes little difference when you gotta get to work and pay the bills. Thank you to all who have educated me and given me confidence. I just hope i never have to change another fuel pump...ever!
 






Why not? Now you know how to do it?
The first pump always takes all day, now you have the confindence and the know how to replace any fuel pump on any vehicle in a matter of hours :)

I was in the same boat as you about 12 years ago when I first got my BII, except I dont have kids. But I did have a BII that needed ALOT of work, no $$$ and limited tools and knowledge, but what I did have was a Prodigy online internet account and modem.......here we are many years later and I wouldnt trade my BII for all the gold in the world (yes I would but shhhh she doesnt know this)

Job well done!
Before you go replacing your starter, what are the symptoms?
Also consider a used or rebuit starter, the factory gear reduction starters are $$$$$
Many times it is the solenoid or wiring to the starter way before the actual starter goes bad.....
 






Congratulations!

Not only have you changed the fuel pump, but you have specialized experience that you can use to answer someone elses fuel pump questions.
And for twenty bucks you can become an explorer elite and get into the secret forums and learn the secret handshake.
 






It may be just the heat ( heat index is 105) But it is only starting some of the time. I am pretty certain that it is the starter and not the wiring.when it does start it is a sluggish start like battery is low but it is new battery. I have had starter trouble before on another ford. I hasnt gone out completely but I will replace it anyway before it does. I was able to get a starter off of a junked explorer for no $.
 






OKAY but here are some things to think about:
Our starters use two solenoids (at least up until 98), the fender mounted unit and a solenoid built right into the starter.
this is why your starter gets two wires to it, one is the small signal wire and the other is the large 12V+ feed directly from the battery.
the starter gets its ground - from the engine block

So the large + wire from the battery is very important to good starter function, I have seen them melted, I have seen them, corroded, etc. It's not a bad idea to check.

The ground strap that goes from the battery, to the frame, and then on to the engine block MUST be in good shape, otherwise, of course the starter will act weak.

the + and - battery cables on these trucks can cause all sorts of issues, and they deteriorate with age. They are not expensive or really difficult to replace, so they are worth at least checking. Many times the corrossion is internal of the wire insulation and hard to find just by looking.....Just FYI

If the starter can only pull 10.5-11 volts from the battery + cable, it will act just like a dying starter......
 






My positive battery cable is corroded but I am not certain how far back. I have cut into the insulation and found that it is corroded inside about 2 inches back from the terminal. I have been putting off replacing it because something else is always needing repair. However I think that this will be next on the list and since I have the starter already I will just replace it at the same time.
 






good idea :)

You can build your own cable using parts from West Marine/ Radio Shack/Stereo shop etc

Or you can get a universal cable from the auto parts places and make it work.
West Marine has saved me alot of $$$ when it comes to power and signal wires for my vehicles
 






I am certain now what it is the starter. Went to fire it up and got a solid click. I tapped on the starter with rubber mallet and it started up. So... as soon as this heat wave is over I will get to work on it. I have not heard of west marine, are they online?
 






Congratulations on the pump repair, that is a big task.

The battery cables, keep an eye on them. The biggest problem with cables, other than surface corrosion, is the practice of cutting the end off. The cheap store terminals that let you bolt the old cable onto them are temporary only. Please be sure that you have battery cables with permanent ends. If you have those mentioned, throw them away, replace the whole cable. Regards,
 






Hi I too am a girl .. Just so you known.. I also am having the same problems .. I did all the cross checking as previously mentioned .. I realized After changing my fuel pump ( thinking that's the problem ) my fuel pump would not turn on .. I remembered a wire that I had disconnected during the change of the pump .. come to find out it was for the inersia switch .. Now I can hear my fuel pump turn on but shortly after she shuts off .. There is power in the inersia switch .. I'm guessing the problem is between the inersia switch and the plug under the truck .. Your advice ... What to do next ... !?!?!?!?'
 






Hi I too am a girl .. Just so you known.. I also am having the same problems .. I did all the cross checking as previously mentioned .. I realized After changing my fuel pump ( thinking that's the problem ) my fuel pump would not turn on .. I remembered a wire that I had disconnected during the change of the pump .. come to find out it was for the inersia switch .. Now I can hear my fuel pump turn on but shortly after she shuts off .. There is power in the inersia switch .. I'm guessing the problem is between the inersia switch and the plug under the truck .. Your advice ... What to do next ... !?!?!?!?'

The pump only runs for a second each time you turn the key on. It runs full time after the engine begins to crank.

The inertia switch virtually never fails, only check the connector wires near it for damage. If they haven't been hurt, by say a big foot kicking them, then they will be fine, and leave that plugged in.


FYI for PATS vehicles(98+ Explorers), check to see if the key is being read by the anti-theft system. Turn the key on and find the dash light which reads "THEFT." That light should never blink/flash. If it flashes after turning the key on, then the key code has not been read, and the system shuts down the pump and ignition. That light is supposed to stay on when the key is turned on, and go off after the engine starts.
 



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Hi Liliu, are you still having problems with your fuel pump? I read through your other posts and you indicate you changed out our full pump correct?

You indicated you can now hear the fuel pump turn on for a few seconds (which is normal).. The fuel pump will remain ON as long as the engine tachometer is sending RPM info (basically if the engine is moving the computer will leave the fuel pump on, otherwise it shuts off 2 secs after the RPMs reach Zero).

When turning the key from OFF to RUN (not start) the fuel pump will come on for 2 secs.. This should pressurize the fuel lines going to the fuel rail(s).. If you find the shrader valve you can press it in slightly to see if gas comes out (wear glasses)..

We can help with your issues provided we have a better understanding of what the problem is and what you've done or check so far.
 






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