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Thread: Is changing fuel pump a noobie project?

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    Is changing fuel pump a noobie project?

    Hi guys 91 miata full of gas’s was on a drive about 30 minutes and the car died no power at all and I am having it towed home. I think the problem is the fuel pump but I am worried about accessing it in the gas tank bc I’m not a pro. Is this a huge job?

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    6,000 rpm - mere mortals would shift HarryB's Avatar
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    No, just a bit tedious. Disconnect the battery first. Need to remove the carpet behind the seats (on the parcel shelf), remove the access panel (a few bolts). Clean up the area over the fuel pump cover before removing it to avoid crap falling in your tank. Remove the fuel hoses and the connector, unbolt the panel, take it out carefully because the fuel sending unit might catch on it. Have a towel ready to not drip gas everywhere. It is worth replacing the in-tank fuel filter (get a genuine Mazda one) and the cover gasket as it will be perished by now. Fuel hoses may also crack during removal, so worth replacing those as well.

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    Individual-1 ☚ ☻ ☛ Agent☣Orange's Avatar
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    I would test the circuit first. Make sure the pump is working (or not) with the ignition on and if not, I'd check the fuse and then power at the pump. If it does need replacement, I'd do what Harry says but I would also take out a seat, maybe both just to give myself room. That parcel shelf panel is held on by 300 bolts so if you have a cordless ratchet, you'd surely save your hands and a lot of time.

    I think replacing a Miata fuel pump is very easy compared to other cars that have to go up on a lift, remove braces, exhaust and maybe a subframe just to drop the whole fuel tank before getting to the pump.


    No todo que es oro brilla.

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    6,000 rpm - mere mortals would shift HarryB's Avatar
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    Good tip on testing the circuit and if needed removing the seat, it is just 4 14mm head hex bolts. You do not need to remove the parcel shelf itself, there's a small access panel right above the fuel pump held on with 6 or 8 10mm hex bolts ;)

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    Oh I forgot about that! It's been a while. Had to google a generic image.

    Looks like 6 bolts
    C51F4381-F30B-480E-8134-769658E01D0F.jpg


    No todo que es oro brilla.

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    https://revlimiter.net/blog/2012/07/...-fumes-i-hope/

    This post isn't about changing the fuel pump, but it does get you there. The panels removed to service the fuel valves are the same ones you need to pull off to get the pump out. Just gotta remove 6 more screws or so.


    The fuel pump is the large item on the right with the hoses.

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    Admin / Pit Boss / Miataholic Phatmiata's Avatar
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    dont forget to change the fuel filter (under the car) since you are doing fuel system work

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    Ninja Messiah kung fu jesus's Avatar
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    Is changing fuel pump a noobie project?

    +1 Test the circuits 1st.

    Step 1: Park outside

    Step 2: Locate and put a fire extinguisher nearby outside the car.

    Step 3: Loosen gas cap to relieve the pressure in the tank. This prevents the golden shower.



    After you remove the fuel pump hanger, lay something (non metallic) over the hole in the tank. This cuts down the fumes and prevents stuff from falling in while you change over the pump.

    I have bought this for 3 separate Miatas. It’s a nice price, inclusive, and OEM brand:

    https://a.co/d/6durlPJ

    Every post above is very helpful.

    Only other caveats:
    Be gentle removing the fuel hanger assembly. The fuel level arm hangs out in space. Same with reinstalling it.

    The two Phillips screws at the base plate under the pump are JIS and a little soft. I have used visegrips clamped to the head of the screw in coordination with a regular Phillips screwdriver just to crack them loose to remove them.

    Check the wiring on the hanger (that goes in the tank) for shorts, burnt connections, etc. Check the connections at the top (outside the tank) for similar damage.

    If your hanger is crusty and corroded, source another used one. SNS Parts can get you squared away (if in the US)

    If you replace the pump and it doesn’t work, holler back. There will be a few steps to check where the fault is (pump relay or circuit controlling relay - they are different)

    Take your time. Good luck!

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    Idling - Listen to it purr...
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    Hi everyone I have replaced the fuel pump and the fuel pump relay and the car will not crank any other ideas? It seems that the engine is not getting fuel. Is there any other fuses I need to check?

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    6,000 rpm - mere mortals would shift HarryB's Avatar
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    When turning the key to the "on" position, can you hear/feel the fuel pump priming?

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    Ninja Messiah kung fu jesus's Avatar
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    By fuel pump relay, do you mean the one under the hood, or the big one up under the dash?

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    When I turn the key to on yes I hear the fuel pump priming and the relay I changed is under the dash, I didn’t know there was one under the hood. Where do I find the hood one passenger side?

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    If you hear it priming, it’s probs something else.

    Can you describe how it died initially and what it is currently doing (crank, no fire etc)

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