Fuel injector repair

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Gloria&Suzanne, Jul 19, 2026 at 11:17 PM.

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  1. Gloria&Suzanne

    Gloria&Suzanne Junior Member

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    The rubber seals are getting worn and the pintle caps are cracked/missing. The first time around, I did not know that there's a way to prevent gasoline from oozing out of the rail during the job, which I caught the leaks with shop paper towels. When I reassembled them after cleaning them and the ports out, the engine ran smooth at idle, but I immediately noticed a gasoline odor. I realized it was because I seated them too loose. I overcorrected this by tightening to 20ft/lbs and put small, thin metric universal rubber O-rings at the base of the nozzles to get them to seat then tight enough that they couldn't move. I was doing this in an attempt to do a temporary fix until the fuel injector parts would arrive, and I'm worried I may have ended up damaging some of the pigtail connector metal prongs in the process of struggling to unplug them, even when pressing on the tabs. When I reassembled it and did a test run, it loudly misfired the moment the engine came on, so I turned the engine off immediately. What was my most likely mistake? Can even something as seemingly trivial as small O-rings on top of the cylinder port grommets cause such a bad misfire?
     
    #1 Gloria&Suzanne, Jul 19, 2026 at 11:17 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    I doubt you're misfire is caused by the o-rings it may be caused by the leak past the o ring big looking atctailmwen it's live and pressurized you may see the leak. When the injectors are fitted to the rail and the spacers are applied under the bolts in the rail tabs and tightened . The fuel injector should be able to spin by your two fingers .
     
    #2 Tombukt2, Jul 20, 2026 at 1:05 PM
  3. ChapmanF

    ChapmanF Senior Member

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    The only things I'm thinking you could have been "tightening to 20ft/lbs" would be the bolts that hold the fuel rail to the head. Because the rail sits on solid spacers beneath those bolts, overtightening them (once the rail is all the way down on the spacers) doesn't really affect the injectors at all. They're sitting there snug in their little O rings and all you've made different is a couple overtightened bolts.

    For the seal to be good, the grommets and O rings just have to be good, and carefully not damaged when reinstalled to the rail:

    [​IMG]
    [​IMG]

    There has been at least one old thread here where someone did not get the O ring ends of the injectors quite properly inserted into the rail (as in the drawings above), and then thought they would simply be pushed in the rest of the way as he tightened down the fuel rail bolts. That led to at least one injector being crushed and needing replacement.

    It's possible that adding something to the grommet beneath the injector, raising its height, could lead to a similar result, but I haven't seen your situation so it's hard to say.
     
    #3 ChapmanF, Jul 20, 2026 at 1:16 PM
  4. Gloria&Suzanne

    Gloria&Suzanne Junior Member

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    I did not smell any gasoline and even a small amount of gasoline can be easy for the nose to detect.
    It's okay for it to be able to spin while in place? I must've overtightened it with the O-rings then. Three electric connectors wouldn't snap in all the way. If the misfire persists after I fix my mistakes, then, it will be time to call in the pros, so I'll have it towed to the mechanic.
     
    #4 Gloria&Suzanne, Jul 20, 2026 at 3:16 PM
  5. Gloria&Suzanne

    Gloria&Suzanne Junior Member

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    And an extra O-ring that wasn't supposed to be there.
     
    #5 Gloria&Suzanne, Jul 20, 2026 at 3:19 PM
  6. ChapmanF

    ChapmanF Senior Member

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    As you saw in the repair-manual drawings I pasted above, it's not only okay, it's a necessary post-assembly test to make sure you've done it right. :)

    (Well, I guess I didn't paste anything that says it's still twistable after the rail is installed, but it generally is.)
     
    #6 ChapmanF, Jul 20, 2026 at 4:44 PM
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