MR2 Owners Club • Question on Rev 3 ISC/IACV hoses
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Question on Rev 3 ISC/IACV hoses

Posted: 25/04/24 11:01
by lista
Hi all, I am wondering where the hoses in the linked image (at the bottom) go to/come from?

My car now has 4a-ge silvertop throttle bodies, all is connected aside from I don’t have an ISC/IACV. I was going to use one from a 4a-ge silvertop or blacktop, but I’m really struggling to get ahold of one. I am wondering which hoses on the diagram are for air?

Am I correct in thinking 1 and 2 are coolant lines, and 3 is an air hose which then would feed back into the throttle body and thus the manifold? My plan would be to make a plate to block coolant lines as they have been rerouted now, include a hose for air to pass back through as it normally would (I think), and mount the unit near the head for the heat to actuate the spring. But I’m struggling to find info on the lines, unless I’m just looking in the wrong BGB, which I very well might be.

Also wondering if this is feasible or I just try to get ahold of a silvertop/blacktop IACV, as I believe the connection is plug and play, and I don’t need to worry about coolant lines. While I appreciate I don’t necessarily require an ISC/IACV with the throttle bodies as I can set them to be open to keep an idle, I’m quite keen to work one in if I can.

Any advice on this? I feel like I’m just confusing myself at this point :facepalm:

Pic here:



Edit: I should mention that I have an airbox over the throttles, they aren’t open.

Re: Question on Rev 3 ISC/IACV hoses

Posted: 04/05/24 12:35
by chrisE
On my rev 3 turbo I've capped off 1 and 2...

3 connects the the air hose just after the air filter but it doesn't matter where exactly before the throttle plate.

It appears the same would apply on the one in your photo.