P0505 - D16y8

Discussion in '6th Generation Honda Civic (1996-2000)' started by Chriscivic, Jan 1, 2017.



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  1. Chriscivic

    Chriscivic New Member

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    Hey all I got a p0505 code and I've tried checking other posts but can't find the solution.

    I replaced the IACV with a new one from Honda and no luck.

    I adjusted the idle through the set screw and air mixture screw no luck.

    Tps was properly calibrated and no luck. The car has trouble staying idle when cold, I have to give it gas to stay idling. When the code pops, the idle is erratic and idles around 1200 Rpms.


    I was just driving down the road and my thermostat was going little over mid way and back down and back up and back down.

    I'm running a skunk2 manifold and skunk2 70mm throttle body.


    Thanks for the help.
     
  2. boofoo

    boofoo Member

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    Any other CEL codes thrown? Does P0505 return after resetting the ECU?
     
  3. Chriscivic

    Chriscivic New Member

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    This is the only code thrown. It returns after resetting. Thanks
     
  4. boofoo

    boofoo Member

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    Do you have a low idle when the engine is cold and a high idle when the engine warm?

    By erratic, do you mean the idle speed surges?
     
  5. Sleeper0

    Sleeper0 New Member

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    Try burping the system you could have some air trapped and need to get them out


    Sent from my iPhone using Tapatalk
     
  6. Chriscivic

    Chriscivic New Member

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    Yes, low idle when starting in morning and then higher idle when it warmed up.

    I burped the system again, car thermostat is good now. Although I still get the code, I sprayed the throttle body gasket and it changed the idle speed. Would a throttle body gasket leak trip this code?
     
  7. boofoo

    boofoo Member

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    Yes
     
  8. Ep3po

    Ep3po Respected

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    How long ago did you do throttle body mod? Did you have this problem before the mod. I would expect that it is the junk2 tb causing the issue.you didn't buy it from eBay did you?
     
  9. Chriscivic

    Chriscivic New Member

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    Hey, thanks for the reply.

    I got the car after an auto to manual swap was half way done with it, and I had to swap to the 2 wire iacv due to I had to purchase the new harness and ecu. In a jam I ordered the skunk2 intake mani and throttle body right from their site. The throttle body gasket was replaced, and that resolved the low idle in the morning, and it seemed to resolve the problem for the most part. Although I don't believe I am there yet to say my problem is completely solved.

    At low rpms and drive in 1st, the idle will surge a little bit. Just a little.

    In the morning the RPMs sit at about 1800 rpm, then drop down to about 1000 and I believe it's just because I need to drop the idle down a little bit more.


    I do notice though that when I turn my heat on, the idle jumps from 1000rpm to 1200rpm. Is a 200 rpm jump normal when the heat is engaged?

    I'm going to drop my idle to about 700rpms, I believe that's about where it should be.

    What are the issues I'll see from when I set my idle, I fail to unplug the IACV?

    Update: today we have beautiful weather here in New York State, about 60 degrees out. My let my car warm up and it's currently idling at 700ish. Why such a durastic change in the cold?


    Thanks
     
    Last edited: Jan 11, 2017
  10. Ep3po

    Ep3po Respected

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    What year is the car? Sounds similar to a problem I had with a old Acura legend years ago it ended up being cracked vacuum lines it would throw the pgm-fi lite on the dash and idle very high like 2000 rpm or so. And was more of a problem when it was cold out than in the summer.
     
  11. Chriscivic

    Chriscivic New Member

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    The car is a 97 civic ex with a y8 in it, I've been driving it today and she's liking the warm weather right now haha.
     
  12. Chriscivic

    Chriscivic New Member

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    Code popped again yesterday, Started to idle at 1500 then popped the code. I unplugged the IACV, and the idle dropped down to 900.

    I reset the code, left the IACV unplugged then reset the idle to 500 RPM.

    What issues would I face if I was setting the idle with the IACV left plugged in?
     
  13. XpL0d3r

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

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    Cold air = more dense air = more fuel required to compensate. In order to better warm the car, the ECU controls the idle when cold, and won't use O2 sensor feedback to control the A/F ratio until the ECT reaches normal temperature.

    As for setting idle speed, you want to set it with everything plugged in, not left unplugged. IACV included.

    You mentioned earlier that you sprayed around the TB gasket and the idle changed? Sounds like that's your issue.
     
  14. Chriscivic

    Chriscivic New Member

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    Hw
    i ended up replacing the throttle body gasket, and that fixed the low starts in the morning, and reduced the amount the time the code pops. Although once in a while it pops
     
  15. boofoo

    boofoo Member

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    Did you torque the TB nuts/bolts to spec?

    What year Civic? Bone stock?

    Do you have an auto or manual transmission?
     
    Last edited: Jan 19, 2017 at 2:07 AM
  16. Chriscivic

    Chriscivic New Member

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    1997 civic ex manual

    Only aftermarket s**t on it is the intake mani and throttle body which are both skunk2 and yes tb bolts were torqued
     
  17. boofoo

    boofoo Member

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    Describe the current idle problem(s) when P0505 appears.
     
  18. Chriscivic

    Chriscivic New Member

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    It's easier to just show you.


     
  19. Ep3po

    Ep3po Respected

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    Like I said above 10 days ago I think it's the throttle body. Do you still have the stock tb on hand still? If you do pop it on there and see what happens.
     
  20. boofoo

    boofoo Member

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    Was the engine fully warmed up or cold in the video?
     


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