2004 Honda Civic LX weird startup behavior when engine is hot
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2004 Honda Civic LX weird startup behavior when engine is hot
So i have a really annoying idle or startup problem with my 2004 Civic LX. When i start it up in the morning while the engine is cold i don't have any problems, it idles high at about 1200 rpms and settles slowly to about 800 rpms while it reaches operating Temperature. But if i start it up while the engine is hot it first surges to about 1200 rpms and then drops to around 350-400 rpms for a few seconds. After that the Engine idles fine. That being said, i don't have any idle problems on traffic lights or stop signs it's just an annoying behavior when starting it up with an hot engine.
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Re: 2004 Honda Civic LX weird startup behavior when engine is hot
First
I would try shutting it down when hot by pulling the fuel pump fuse. After couple of seconds the engine will stall out, then turn key off and reinstall the fuse in that order. You want the fuel system depressurized.
Now wait your “normal amount” time that a restart would fail and then put key in, turn to run, but wait a couple seconds before turning to start.
If it starts without issue, drive for a minute or two, shut down, normally and restart with normal delay to see if acts up, if it does repeat pulling the fuse to verify that solved the issue.
Next steps would be to get a better than basic code reader that displays live data and get reading for your map and temperature sensors and report back.
I would try shutting it down when hot by pulling the fuel pump fuse. After couple of seconds the engine will stall out, then turn key off and reinstall the fuse in that order. You want the fuel system depressurized.
Now wait your “normal amount” time that a restart would fail and then put key in, turn to run, but wait a couple seconds before turning to start.
If it starts without issue, drive for a minute or two, shut down, normally and restart with normal delay to see if acts up, if it does repeat pulling the fuse to verify that solved the issue.
Next steps would be to get a better than basic code reader that displays live data and get reading for your map and temperature sensors and report back.
If you think a good mechanic is expensive, try hiring a bad one
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Can u tell me how to do a idle relearn? I usually just disconnect my negative battery terminal for a few minutes but i read that there is a way where u rev the engine to 3000rpms for 5 minutes.
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The forum search button works wonders...
At the bottom of the first post.
https://www.civicforums.com/forums/3...e-posting.html
At the bottom of the first post.
https://www.civicforums.com/forums/3...e-posting.html
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I guess I'm just going to clean my iacv and do a idle relearn afterwards. Because i haven't cleaned that at all since i own that car.
no i don't have a Check Engine Light. If you think a good mechanic is expensive, try hiring a bad one
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Well i used to have a CEL when i disconnected my AIT Sensor to test if that is the reason for my problem. That being said, my CEL Works. I went to Advance Auto to get a code scan and well surprisingly no codes present. I'm gonna get some throttle body cleaner now and start cleaning it.
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Just wanna let you guys know that my idle is fixed now. There was a lot of gunk in the IACV. Thanks for your help. While i was doing the repair i discovered a broken engine mount which would describe the vibrations during idle.
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