This car has begun to surge badly at idle, idle irregularly and too fast > 1200 RPM. I suspect the electronic air control valve (EACV) is dirty because it has never been removed or disassembled since the car was built. The car now has 270,000 miles and has been well maintained. However, once I removed the EACV I could not see anyway to disassemble it in particular to clean the internal piston and the cylinder in which it runs. The EACV is a DENSO 138200-0310 (M5A) and the Honda part number is 36450-PW1-GO1. The Denso EACV appears to be identical with AIRTEX 2H1108, which is listed as an aftermarket substitute.

Does anyone know if that Denso EACV can be disassembled and if so how?

 

Yes, u must disconnect 2 coolant lines that connect to it. You'll lose a little coolant when u do this. There would be 3 screws on the top to remove and I think people say to use brake clean to out the part.ive done this last summer. Don't lose the two rubber gaskets. One gasket is under the lid when u remove the 3 screws. The other one is a figure 8 shape where the the holes are. Some personal people recommend replacing the gaskets but I just used the old ones

 

I just soaked the whole unit in brake clean. I couldn't get the internal piston out either. After cleaning it, the car doesn't surge any more