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  1. #1
    FEP Power Member gmatt's Avatar
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    Default fuel pump question

    '86 LTD, 3.8. had a no start situation this morning. Engine cranked without starting. Turned the ignition to the on position, did not hear the pump prime. Couple hours later, tried again, started right up and I did hear the pump. I was going to check for voltage at the pump with switch on, but since it started I figured it obviously had power. So now I'm wondering why no power earlier? Ignition switch? I'm thinking no since it cranked. Relay or ecm? Something else? Any ideas or insights are appreciated.

  2. #2
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    I love intermittent electrical problems that you can't recreate and diagnose. Are you having any other ignition switch on power issues (turn signals not working, radio, HVAC, etc.)? Just because it did crank doesn't mean the ignition switch isn't failing. It could be a lot of things and I wouldn't rule anything out just because it started working again. It may have had power at the pump when it worked, but that doesn't mean it had power there when it didn't work. Relay, fuel pump, wiring. I like to start with the simple/easy/cheap stuff, but it's hard to know what direction to go if you can't get the failure to repeat. You can start by checking electrical connections and wiring. Pull the relay and physically check it. I've had issues with Ford fuse boxes where everything looked great on the top, but on the back/bottom were corroded wires making intermittent connections.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
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  3. #3
    FEP Power Member gmatt's Avatar
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    Name:  P1370847.jpg
Views: 65
Size:  286.2 KBIt has started ok several times since this morning, but i swapped out the pump and filter since I had new ones on the shelf. The terminals on the old pump were pretty corroded.

  4. #4
    FEP Senior Member
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    Sooo bad fuel pump and now everything is good?
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  5. #5
    FEP Power Member gmatt's Avatar
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    Been driving it with the new pump for a week. 50 to 90 miles/day Highway, side streets, no problems. It may be my imagination, but it seems to run better. Not that it was running bad before all this.

  6. #6
    FEP Super Member gr79's Avatar
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    Good deal. It has to run better with a new pump for whatever reasons.
    Starters, alt, fuel pumps, relays stick, batteries, brakes, tires, wear out slow or quickly.
    Spare known good relay wont hurt having around.
    Wiring, connections, grounds, can and do deteriorate over a 34 year span.
    The unseen faults that show up on the road.

  7. #7
    FEP Power Member gmatt's Avatar
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    Quote Originally Posted by gr79 View Post
    Good deal. It has to run better with a new pump for whatever reasons.
    Starters, alt, fuel pumps, relays stick, batteries, brakes, tires, wear out slow or quickly.
    Spare known good relay wont hurt having around.
    Wiring, connections, grounds, can and do deteriorate over a 34 year span.
    The unseen faults that show up on the road.
    I was thinking the pump wasn't getting a full 12V with the corroded terminals. And yes, I have a lot of spare parts on hand.

  8. #8

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    I was going to guess ECU because I have one that works perfectly except it won’t run the fuel pump relay .....
    -- James

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  9. #9
    FEP Power Member gmatt's Avatar
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    Quote Originally Posted by erratic50 View Post
    I was going to guess ECU because I have one that works perfectly except it won’t run the fuel pump relay .....
    Hopefully I don't have to worry about that. An ecu is not in the cards.

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