t2d2

iTrader: (8)

I don't know why it never occurred to me until now when various IAC Valve discussions have come up... Conventional wisdom is that the '95 (and '96?) IAC Valves are not serviceable because they are a sealed, one-piece unit, unlike the earlier '92-94 version that can be disassembled.

While doing some porting and shaving of my '95 intake plenum to eventually put on my '94 SC400, I realized there's a good chance the '92-94 IAC will work on it. Has anyone tried it? The mounts are a perfect match. (As is the electrical, I believe, but that would only be an issue if using the '95 IAC on my '94.) The part I'm unsure of is whether the plenum has any differences to account for the different IACs?

Here are a couple pics to help. I couldn't find a good shot anywhere of what the IAC tube looks like on the '92-94 plenum. I think the tip that extends on the valve to block the tube is shaped a bit differently, so it's possible there's a difference where it seats in the respective tubes.




Upside down, looking at the tube into the '95 plenum for the IAC Valve.




'92-94 IAC Valve on top (less the valve itself), '95 on bottom.


If it turns out they are interchangeable, that could be a big help to people with the one-piece valves that have problems requiring cleaning to troubleshoot.

t2d2

iTrader: (8)

Here's another pic I had lying around of the '92-94 valve.



You can see it has a much more rounded/tapered tip than the very flat/broad tip in the '95 IAC pictured previously. I'm thinking either one will work, with the only difference being how far the valve has to modulate in order to open or block the tube, given the different tips. Of course, another wild card is whether that difference affects the ECU.

t2d2

iTrader: (8)

One more picture, to compare against the first one in post #1:



Supposedly a '93 plenum on top and a '95 on bottom.

That's the best comparison I've managed to find. Unfortunately, the shading makes it tough to tell if there's any difference at the seat of the tube.

t2d2

iTrader: (8)

I finally have a '92-94 and '95 plenum side by side, and it turns out the seat of the IAC tube is indeed different.



'95 on top, '92-94 below.


The '95 has a very squared up seat that protruded further into the tube, while the '92-94 has a sloped one that doesn't protrude very far (it almost looks smooth until cleaning it up a bit). Whether or not that means the much more common '92-94 IAC valve will work on '95-96 plenums is still an unknown, but I'm less confident now that it's a viable alternative to people in need.

It's odd that the plenums aren't identical as thought, despite keeping the cold start injector mount around because it's an otherwise "identical" item.