Honda Civic SiR
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Honda Tips and Tricks
This page contains some of the tips and tricks that are useful
for general maintenance of your Honda. At the moment there are
only instructions on how to set the idle.
Setting the idle correctly on a Honda Civic (or any Honda) is
important. If the idle is not set correctly the car will either
idle too low, or it will idle too high causing the idle to surge
up and down.
Instructions to set the Idle
- Warm the car up to operating temperature. This is generally
determined when the radiator fan turns on if the car is
- Unplug the IACV valve on the back of the intake manifold.
This needs to be done because the IACV valve is what the ECU
uses to dynamically control the idle by allowing more or less
air to bypass the throttle plate. Be careful not to burn
- Set the idle to 600rpm using the idle control screw. This
screw controls the static amount of air that bypasses the
- Turn the car off and plug in the IACV valve.
- Reset the ECU.
This needs to be done because the ECU will have thrown an
ECU error code.
- Restart the car. The idle should be running nice and close
There are other things that can affect the idle, but these are
much less likely.
- The throttle plate is worn or is not closing far enough and
and is letting too much air past. If this is the problem then
you would not have been able to adjust the throttle down to
600rpm with the IACV valve unplugged. Check the adjustment of
the throttle stop to make sure that the throttle plate is
- The voltage of the throttle position sensor is not correct.
It should read 0.5V when the throttle is closed and 4.5V at
WOT. This is not easy to test. Refer to your Honda Service
Manual for instructions.
- Other gremlins, which I haven't remembered...