Welp community, I'm 0 for 2 on 'quick' clean procedures. I followed the various guides available, given the car is a 2005 with 147k+ miles and having issues with idle drop. I replaced the PCV, then went after the IAC. I cleaned/brushed it out, reassembled everything, and started up the car. For the first 30 seconds or so, there are no issues. After that, the idle cycles every second between 1,500 and 3,000 RPMs or so. I saw a comment from Billman250 from another IAC post where indicates this is almost always a stuck IAC rotary valve. I pulled the assembly back apart to see if it was stuck. It's not acting 'stuck', but it also doesn't look like it's closing all the way. I reassembled and still had the issue. Took it apart a third time and took a few pictures and a video of the rotary valve.


Any feedback would be fantastic, as the next step is to grab a torx screwdriver and pull the motor assembly apart. Thank you.

 

Idle relearn procedure ?

 

Because it's such a consistent, cyclical surge in idle, and only started happening after i cleaned the valve assembly, I'm assuming it's something with the valve assembly itself and no related to the learning ECU. That said, I'm willing to try anything, so after I put the valve assembly back together i'll give it a shot.

 

Did you remove electric motor from mechanical rotary valve while cleaning?

 

Not yet, that's what I'm doing today. I've got to find a 5 point screw head as the torx size T20 is 6 point and doesn't fit.

 

Yep you will need a tamper proof torx bit set. Had to special order a set on Amazon. It really makes the job easier and then you truly are able to clean the IACV

 

I've had the problem with the idle bouncing to 3k and back down every second. I couldn't determine exactly the issue but it seemed to happen sometimes after cleaning the idle air control valve. What I ended up doing was driving on the highway and doing very hard pulls to the top of third gear. After highway driving and pulls I would pull off and exit and the idle would be stable. Not really scientific at all but give it a shot. My guess is that it had something to do with ECU relearning something..

 

https://www.s2ki.com/forums/s2000-un...-895678/page3/
https://www.s2ki.com/forums/s2000-un...stment-928403/

I followed Billman's and Ado's instructions from the above threads. At least for me, a Torx T20 did NOT fit. My screws had some kind of special security 5-point star fitting. I took the IAC assembly to a local hardware store. The only 5-point they had was part of an expensive 148-piece set. The guy I talked to was cool. He pulled the piece out of the set, and I bought a small thing of light oil and fixed it in the store. I pulled the motor off the IAC housing, taking note of the orientation of the valve assembly, and made sure the spacers were there. Then I tried to spin the shaft. Although it would turn, it was extremely sticky. I put a couple drops of oil in the bearings and spun/wiggled the shaft several times. Shortly after the oil worked its way into the assembly, the shaft was free-spinning. I put the motor back on and gave the guy the 5-point piece back. That process took all of 3 minutes.

I'm assuming that blasting the TB cleaner in the assembly shook loose some dirt and/or blew out some grease which resulted in binding up the shaft in the bearing. I put the assembly back in the car, and problem solved. I went back afterwards and did the ECU reset process for good measure. The car has never idled so well since I've owned it!

Thanks all for the input.

 

Great to hear and solid info for the community, perseverance in solving the issue is so rewarding.

 

Splitting the halves and freeing up the shaft is the only way.

No cleaner of any kind is needed. Using cleaner can actually add to the sticking of the valve, as the clearance is very close.