Acura MDX SUV Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1
Hi everyone, I just bought a 2006 MDX with 159K miles.

I'm trying to figure out what this part is on the left (passenger side) of the engine. I haven't had any problems with the car, I'm just curious.

It is Denso part # 012010-1010 also known as Honda part number 17150-RCA-A01.

It is called the "Bypass Valve Actuator Assembly".

I've been trying to figure out what it does but I haven't found any answers on the web.

The SUV runs perfectly, I'm just curious about it.

Is this similar to an "idle air control valve" (IAC or IACV)? I read that the 2003-2006 MDX does not have an IACV since it has a drive-by-wire throttle system.

I attached two pictures of the part.

Thanks for any info you can provide.
 

Attachments

·
Registered
Joined
·
3,338 Posts
That is the IMRC motor (Intake Manifold Runner Control).. Almost all J-Series Intake Manifolds are/were 2 Stage meaning there is a different air chamber charge in the low rpm Vs high rpm... When you pass a certain RPM threshold that motor opens up a butterfly in the manifold and allows it to breath air from both chambers this in and VTEC allows for a higher HP output while adding low end torque.

FYI: 2 Stage Intake Manifolds were equipped only in Sports Cars before, The first brand to commercially use it was Porsche.

Before updating the IMRC design the Motor hanged from behind the Intake Manifold and was actuated by a wire:
 

·
Registered
Joined
·
3,338 Posts
Explained a little bit more:
If you see the design of the Intake Manifold you can notice there are 2 distinctive "humps" in it, One in the front and One in the Back..
Those chambers feed 3 cylinders each. This method creates back pressure meaning it can add some low end torque but at higher RPMs it creates a restriction.. So in order to feed more air the butterfly sits in the middle of both chambers, When the engine raises the RPM that butterfly opens and all 6 cylinders can get all the air. If that IMRC motor failed it will mean the engine will choke on the higher RPM.
 
1 - 5 of 5 Posts
Top