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Fuel Pump Blues with some questions

Discussion in 'Stock 1991 - 1994 Explorers' started by Mudboy, August 2, 2011.

^^Searches ExplorerForum.com^^





  1. Mudboy

    Mudboy Active Member

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    About a week ago when my girlfreind went to start the vehicle she said she wasn't getting any fuel and it wouldn't start, I went out there and it fired right up. Over the past month or so it has been slow starting. There were also a few times where the thing would start and run real ruff for about 15 seconds before clearing out. Slow starting to me sounds like either one of three things. Fuel Filter plugging, fuel injector sticking, or fuel pump not putting out enough pressure. This weekend I was going to change the fuel filter out since I havent done it since I bought the vehicle and have ran the tank pretty low a handful of times. One thing i did do over the weekend was shut off power going to the fuel pump after the vehicle was sitting for an hour or so and it fired up after its 5 seconds of cranking or so. That should be telling me that it held fuel pressure and none of the injectors are leaking by. Well thats by previous conditions.

    When i first bought the vehicle the previous owner told me he had to wire in a toggle switch due to fuel pump issues. I never bothered tracing the wires until yesterday when I couldn't get the vehicle to start. They went into the wire that supplies power to the inertia switch( I believe green and yellow). So what it was wired up as was a shut off switch which made no sense to me. I cut out the butt connectors, checked to make sure the switch wasn't tripped and decided to bypass the switch by cutting the other wire (Red i believe) and splicing the two together. still nothing. At this point I was starting to run out of daylight so I ran to the parts store real quick and grabbed a relay and a test light. The aftermarket relay which matched the ford # was a 5 prong compared to the factory 4 prong, however the connector had room for the 5th prong but that port was just a dummy with no wire going to it. I figured this should be fine. I plugged it in and still nothing. The next thing I did was take the test light and made sure I was getting power to the back of the relay at the port were the green and yellow wire that feeds the inertia switch had power. It had power so at that point i believe I provedc out that the relay was good and supplying power to the inertia switch. Next thing i did was unplug the inertia switch and checked to see if i was getting power to it. This is where it started to get weird. With the key off i was getting a very dim light on the test light, when cranking the light got brighter which i expected. I just don't understand why there is a small amount of power going to the inertia switch even with the key off. I'm guessing this why the previous owner wired in a toggle switch because A) the pump waws always running B) it was draining his battery.

    Am, i correct when I say that the fuel pump circiut consists of this is this order. 12 volt source from battery to 30 amp fuse to relay to inertia switch to fuel pump? Am I missing anything? also should it be 12 volts all the way to the fuel pump.

    Sorry for writing a book but I figured I'd be descriptive.
    Thanks.
     
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  3. Mudboy

    Mudboy Active Member

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    . The 5 prong relay is fine as long as the 5th prong does not get power to it. I should only expect a short life of this new relay since it is not motorcraft. The EEC Relay could be bad, so I will check that when I get home. the EEC itself could be bad, I may have to fine an alternitive way to turn the fuel pump on. There is a test port for the fuel pump # 6 pin of the VIP connector (trapezoid shaped) that I should be able to run a ground too and it should turn the fuel pump on. If that doesn't work I will run a hot wire to the one wire coming out of the inertia switch since it's a straight shot to the battery. Fuel Pump and EEC relays should be 30 AMP. Found a print that i can actually view from work showing the VIP connector. (can't view photobucket pics from work due to firewall). Should get 13 volts going to the pump during the first few seconds after turning the key on.

    So after a few hours of searching I got most of my answers i believe. So when i get home. i will test both the new and old relays along with the EEC relay. I will measure the voltage at the back of the relay then down at the inertia switch. If all tests well i will ground out pin 6 of VIP connector. If that doesn't work I will run a hot wire as close to the pump connection as possible (drivers side frame rail behind tank). If that doesn't work then It will be fuel pump time. Looks like if thats the case, I'll be doing the hole in the floor option.
     
  4. Mudboy

    Mudboy Active Member

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    Anyone have a preference of brand name? or any to stay clear of? oh yeah Motorcraft is not an option it costs more than a third of what I paid for the vehicle lol
    Looks like rockauto has:
    SPECTRA PREMIUM $83.79 complete with strainer and sending unit, 12 month warranty
    AIRTEX $84.79 complete with strainer and sending unit, no mentioned warranty
    RETECH $77.79 complete, reman, bench tested, 12 month warranty
    CARTER $110.79 complete, bench tested 12 month warranty
    DENSO $133.79 not much info, 12 month warranty
    BOSCH $176.79 complete, new technologys, 12 month warranty
    MOTORCRAFT $346.79 complet, bench tested 12 month warranty
     
  5. Roadrunner777

    Roadrunner777 Well-Known Member

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    I just installed Airtex, it does include a 12 month warranty, but you must purchase a fuel filter at the same time and, apparently on the honor system, install it.
     
  6. Mudboy

    Mudboy Active Member

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    cool, thanks for the reply. i have heard horrible stories on teh Airtex. I hope it's just from people that don't believe a cheap part can be any good. Anyone got some extended time on their airtex?
     
  7. Mudboy

    Mudboy Active Member

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    checked all power with my Fluke, everything looked good. I figured for the hell of it I'd kick the tank and see if that worked, sure enough, kicking the tank made the pump come on. I believe this is a sign that I will be replacing a pump in the near future. How long do I have from a previously expierienced kickers opinion?
     
  8. Mudboy

    Mudboy Active Member

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    Alright. Fuel Pump completeley died last night. Not this weekend but the folowing I'm going to replace it. I need to know some opinions on what pump to order though. What have you had good luck with, what has dies in a few months. I'm going to drop the tank, clean it and cut the access panel as well.
     
  9. mange1234

    mange1234 Active Member

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    I suggest that you pull out the PCM and check it. There are three capacitors in the PCM which leak electrolyte and corrode the board.

    It is very easy to pull the PCM (in the kick panel on passenger's side) and the cover come off easy with removel of two small screws, exposing the solid state circuit board. Inspect the three 47 micro Farad capacitors. It it will be obvious, right away, if one or all are leaking or burnt.

    I had fuel problems, went to the PCM and saw the problem right away. I had one bad capacitor. Soldered in a new one from Radio Shack, and Explorer runs fine now.

    Good luck.

    Mike in Virginia Beach
     

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