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Problems with P0505, two codes showing up?

Discussion in '6th Generation Honda Civic (1996-2000)' started by Erny, Jan 11, 2018.



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  1. Restotech

    Restotech Respected

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    Suspected external vacuum leaks can be identified by spraying carb, or throttle body cleaner in the suspected area and the idle will increase drastically.
     
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  2. Erny

    Erny New Member

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    Thanks, only knew about soap and water lol
     
  3. Restotech

    Restotech Respected

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    You can also pinch vacuum hoses, using needle nose pliers, going to the intake and the idle will drop lower if you find the ciurcut introducing to much air
     
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  4. Erny

    Erny New Member

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    That's so simple I feel like it should've crossed our minds at some point haha, thanks for the tips.
     
  5. boofoo

    boofoo Respected Registered VIP

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    I agree with Resto on checking whether the throttle cable is adjusted too tightly. The cable should have some slack. However, that would not throw P0505.

    Did you replace the IM and TB gaskets and torque the nuts and bolts to spec?

    Do this test:
    1. Remove air intake.
    2. Start engine.
    3. Use your finger to cover the hole leading to the IACV.
    4. Does blocking air entry into the hole cause the idle speed to drop substantially?
     
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  6. civteck

    civteck Respected

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    Iv seen even the best looking vac hoses have slight cracks that bleed air. Try this trick with the engine warm and steady idle, high or not, the engine should rev if a vac leak is sprayed. Go around all hoses and gasket surfaces. Did you set mechanical timing after swap? At this point with info provided 1) vac leak 2) iac sticking 3) timing. Let us know what you find

    Sent from my boujea ass phone
     
  7. Restotech

    Restotech Respected

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    I would try this first. I have used this method and found too much air through my fitv.
     
  8. XpL0d3r

    XpL0d3r What Civic? Staff Member Registered VIP Registered OG 5+ Year Member 10+ Year Member

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    You kept the IACV on the manual, right? Making sure, because if you swapped the one over from the automatic, 99-00 IACV's are different between auto (3 wire) and manual (2 wire).

    I agree with the others on checking your throttle cable. Pull your intake and take a look at the throttle plate. Make sure it's fully closed. I know you said you cleaned the IACV, but if the throttle plate is dirty, clean that up too.

    I had a P0505 issue with my RSX last year, along with an idle higher than normal. I cleaned / replaced IACV, checked the cables and hoses, etc. It turns out the TPS was off calibration.
     
  9. Erny

    Erny New Member

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    So I'm kind of putting some puzzle pieces together because the original motor over heated for a pretty substantial amount of time and either that or something else warped the Intake Manifold and wasn't seating on the gasket right and therefore caused a vacuum leak.
     
  10. Erny

    Erny New Member

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    it wasn't extremely warped or anything severe we ran a bead of rtv around both sides of a new, cheap O'Reilly gasket. Waited til it got tacky and tightened the nuts and everything looks nice and sealed. Going to wait for the RTV to finish doing its thing to test it tomorrow afternoon.
     
  11. Erny

    Erny New Member

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    I've also found that a 12mm ratchet wrench makes removing the manifold much easier.
     
  12. Restotech

    Restotech Respected

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    From my experience, gas eats or softens most forms of rtv or silicone. Due to the injectors being so close and gas passing by the gasket I wouldn't think this would be a lasting solution.
     
  13. boofoo

    boofoo Respected Registered VIP

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    Use a torque wrench to tighten the IM and TB nuts and bolts to spec.

    If the problem persists, do the IACV test I mentioned.
     
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  14. Erny

    Erny New Member

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    So the leak is still there but it's a lot smaller than it was, i saw someone was selling the whole head and I was wondering if it would be worth it just to get a new head gasket in there aswell as get rid of the leak, or should i just get a new IM
     
  15. boofoo

    boofoo Respected Registered VIP

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    IACV TEST!

    Did you use a torque wrench?
     
  16. Erny

    Erny New Member

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    problem solved! The IM support was loose and causing the manifold to tilt downward & didn't let the gasket seal right, torqued everything down and tested with carb cleaner, everything is running fine so far. thanks for the help guys!
     
  17. XpL0d3r

    XpL0d3r What Civic? Staff Member Registered VIP Registered OG 5+ Year Member 10+ Year Member

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    It appears that this was the solution to the problem. ;)
     


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