Making slow progress on my '00 EJ22 into a '99 EJ25 OB. Engine and trans are in. In the process of swapping over the wiring harness off the 2.5 onto the 2.2 engine. Some of the items are simple plug 'n' play, but, obviously, some things are not. I'm in the early "digging in" stages of the harness swap. My repair manual is pretty useless on helping me identify some of the stuff. (I know the major engine parts and accessories, but some of this little stuff I can't identify at glance.) So, here are a few photos with some questions. Any constructive feedback is appreciated.

 

OK--this is off the '99 OB EJ25. Completely different from the EJ22 manifold here. What exactly does this control/monitor?

 

 

 

 

And this is off the 00 EJ22--different from the EJ25. What exactly does this thing control/monitor?

 

 

 

This is right below the part circled in the above photo on the 2.2--also different from the 2.5

 

 

 

 

And, here are the two intakes--EJ22 on top and EJ25 below. The major differences between the two are circled.

On the EJ25: the UFO looking thing on the driver's side is the EGR valve. The item just to the right of the throttle body is the IAC (idle Air Control) valve which controls how much extra air is let in at idle.

 

Not sure on the EJ22 manifold, but the top part looks like it may also be an IAC valve.

the top photo and passengers side gizmo is an idle air control valve.

 

often if the connectors are the same but it looks a little different, just plug it in and it will work just fine - they're not complicated sensors or anything, just solenoid-type stuff. so if it plugs in they have always worked for me.

 

but if the idle control motor simply swaps too, then just swap those.

 

that EGR and idle stuff might have the same connectors though, if so i'd just plug them in and roll. actually what i did was to remove the EGR stuff altogether. as an aerospace engineer introduced unreliability just doesn't make any sense, but i don't have to worry about emissions here.

You will be doing without the EGR valve

 

 

As for the IAC. Problem stems from he fact that the Phase II engines(in this case you're 2.2) will have 6 pins for the IAC (sometimes called the "bypass air control valve")

 

The earlier phase I engine (the DOHC 2.5) uses only has 3 pins.

 

I think it would be possible to use the 3 wires in you're phase I harness to connect to 3 of the Phase II IAC pins and give it minimal functionality.

 

I have been interested in trying to overcome this hurdle. It's the same issue that I've hit trying to put an SOHC forrester EJ25 into a 90 Legacy.

 

Read Mellow's write up about it in the USRM. He just left the Phase II IAC disconnected and it runs fine once warm. He unbolted the Phase I IAC and ziptied it onto the manifold so the connector had something to plug into, so no CEL. But it just dangles and doesn't control anything.

 

A good diagrahm of the Phase II type IAC is needed. Anybody got the wiring daigrahm for PHASE II engines?

Thanks for the helpful feedback!

 

 

The 3rd photo, the plugin says DENSO--what will it control?

the things on your 2.2 look to be maybe a map sensor and your IAC. Looks like somewhere along the line subaru moved it to the throttle body like the phase 2 ej25s.

 

what i would do it find you an older 2.2 intake with the IAC mounted to the side of the intake. then it would be a plug and play thing.

 

the only thought about that would be if the intake manifold mounting would be the same between the older 2.2 intake and the newer 2.2 heads. i know they changed the 2.5s between phase 1 and 2. if you take a picture of the underside of your 2.2 intake i can look at my pile of intakes and at least see if it's the same.

 

and what gloyale says about your egr you need to keep in mind if you have to go through any kind of inspection, with it unhooked you are going to have a check engine light on all the time.

I have been interested in trying to overcome this hurdle. It's the same issue that I've hit trying to put an SOHC forrester EJ25 into a 90 Legacy.

 

just use a 1.8 TB, they have the IAC mounted to the TB. I'm pretty sure the 2.2 ecu would run it, it's the exact same plug and the 3 wire kind, just in a different place