shaky idle
09-14-2011, 07:38 PM
#11
Registered User
This happens to me ALL the time, seems like after I clean the throttle body it gets better for a bit (Not 100%) but within a week its back to doing it again. The idle drops below where its supposed to and then quickly gets back up.. Never did find a real solution.
09-15-2011, 07:27 AM
#13
Moderator
Clean the IAC valve.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. Just whip the shaft free with your finger, use no cleaner at all. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. Just whip the shaft free with your finger, use no cleaner at all. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
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TKY (04-03-2020)
09-22-2011, 01:39 AM
#14
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Clean the IAC valve.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. clean this out with cab cleaner, blow dry it. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. clean this out with cab cleaner, blow dry it. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
09-27-2011, 08:55 PM
#18
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Many thanks Billman!! I had previously tried to clean the IAC valve but did not take off the motor to clean the barrel. Thought my gas cap was the problem but quickly discovered that was not it. After cleaning the IAC valve as you described, my idle is back to normal. I did remove the computer backup fuse to reset the computer and after it relearned all seems well. Many of your tips and techniques have helped keep my S2000 running at it's best.
12-28-2011, 10:39 AM
#19
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Clean the IAC valve.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. clean this out with cab cleaner, blow dry it. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
You will need a special tool called a pentacle bit. It's a five point torx.
Remove the valve assy.
Take the electronic motor part off the valve with the pentacle bit. BE CAREFUL...there are 2 tiny special shaped spacer plates between the valve and the motor. Work on top of a clean towel, dont loose them. Put it aside. Don't clean it at all in any way. A light wipe with a dry rag is ok, but it wont need it.
The VALVE part has a rotary shaft inside that spins 360 degrees. if it is sticking, the ecu input to move this valve will lag, and you will get the idle dip/shake/come back up. clean this out with cab cleaner, blow dry it. Even add a drop of oil to each end to the tiny shaft bearings.
Spin that shaft with with your fingers till it spins free and smooth.
I used a dremel to slot the screw heads since I could not find a 5-point bit.
I then attempted to remove the rotary shaft by lightly prying on the end of it. DO NOT DO THIS. It's a brittle magnet which instantly broke into pieces. Major bummer. I'm assuming now Billman's instructions meant to just rotate the shaft to clean it, not remove it.
Anyone have an IAC valve to sell? I think the part number is "36460-PCX-003 VALVE ASSY., ROTARY AIR CONTROL" for my '04. Is the same one used on '00-'05? What changed in '06?
12-28-2011, 03:12 PM
#20
Moderator
I NEVER said remove it 
please read carefully. I likely have one laying around.
00-05 valves are all the same.
06-09 does not have an IAC valve, as idle is controlled by the electronic throttle body.
please read carefully. I likely have one laying around.00-05 valves are all the same.
06-09 does not have an IAC valve, as idle is controlled by the electronic throttle body.