Idle RPM and rough idle

Sivvic

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When at stop in Drive with brake on RPM is 647-653 and there is rough idle. When I turn on headlights the RPM increases to 710-715 and rough idle diminishes. I know turning on the headlights increases electrical demand hence uptick in RPM. Is there any way to increase the RPM without increasing the load on the engine by turning on an accessory?
 

nd4sped

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This is a good video on the different things you can do to help resolve idle issues.

 


Glogo

New Member
Thanks I watched this and have tried all the suggestions. It did'nt resolve the issue of RPM just below the threshold of smoother idle that gets fixed when I turn on headlights i.e. more demand on engine to cause RPM to increase to sweet spot.
 

nd4sped

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So the Idle Air Control Valve is what controls allowing more air into the engine to raise idle when there is additional need to increase rpm, thus spinning the alternator more to provide more amperage when high power needs are required. This also includes when you turn on the AC or turn the wheel and higher pressure on the power steering is required.

If the IACV is faulty it can cause a number of idle issues, from low idle, high idle or erratic idle (jump up and down). A lot of times cleaning out he IACV resolves these issues. If you manually power the IACV while installed you can also verify its function.
 


Glogo

New Member
So the Idle Air Control Valve is what controls allowing more air into the engine to raise idle when there is additional need to increase rpm, thus spinning the alternator more to provide more amperage when high power needs are required. This also includes when you turn on the AC or turn the wheel and higher pressure on the power steering is required.

If the IACV is faulty it can cause a number of idle issues, from low idle, high idle or erratic idle (jump up and down). A lot of times cleaning out he IACV resolves these issues. If you manually power the IACV while installed you can also verify its function.
Is there an IACV on 2010 Civic with 1.8L?
 


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