This works w/all the non-EGR EJ22's (most manual cars from '95-98, and any '90-94 EJ22) and should work on the non-EGR JDM EJ25's, too,  and doesn't require drilling/tapping the driver's-side cylinder head. (You'll need to get a single-port exhaust header/y-pipe for the '96-'98 EJ22.) BUT REQUIRES an EGR-equipped intake manifold ('95-98) from another EJ22.

 

EGR = Exhaust Gas Recirculation valve

 

Edit: Also, the EJ18 from the Impreza should work. (Thanks to Matt167 for the reminder.) But be aware that it gives up 50Hp/Torque to the EJ25.

 

This modification eliminates the EGR pipe that originally attaches to the EGR valve on the IM and the driver's side cylinder head.

 

See pic (from EJ25, but same idea on EJ22):

 

This REQUIRES an EGR-equipped intake manifold ('95-98), but changing the intake manifold (IM) isn't that tough, esp. w/the engine out (remember - the EJ22 SOHC and '96-'99 DOHC use different IM's- not interchangeable!). I don't know of anyone that's successfully bypassed the EGR valve by using a resistor or any other electrical modification.

 

I've put over 2K miles on this and not had an issue. NO CEL/Check Engine Light. Car's MPG is still the same.

 

Installation info:

 

Overview of what I did: I ran a hose from the EGR valve and T'd into the IAC hose so the EGR valve sees flow...it doesn't care where it's from apparently.

For the EGR valve connection, I found 2 fittings @ the ACE hardware store that fit together. I believe it's 3/4 that screws into the EGR valve on the IM, then a 1/4 barbed fitting. Put some thread tape on to seal it...it screwed in tight w/out any issues:

 

I then ran short piece of PCV hose into a 90° elbow. PCV hose is same ID as the breather hose on the valve covers.
Here's the EGR-side installed:

 

From the elbow I ran another piece of PCV hose to a reducer fitting w/a short piece of PCV hose from the T-fitting in the IAC hose, as the IAC hose has a larger ID than the PCV hose I used.

 

Final installation:

So far, I've not had a CEL and car runs the same as before. (Don't tap into  the breather hoses as you'll have blue smoke out the tailpipe! )

 

EDIT: I did this same mod on my '96 Legacy (bought 8/2015) when I used the EJ22T heads (no EGR port), and on 10/25/16 I got a P0400 EGR code. I cleared it and it came back next time I drove the car. I replaced the BPT - back pressure transducer - that sits on top of the EGR valve and has 4 vacuum lines connected - 3 on top; 1 underneath. No codes after a week's worth of driving. I used a TOYOTA part that I PullandSaved months/years ago. I guessed this was the issue, and it takes about a minute to swap it out.

Thanks again for the input from everyone on here and to member 987687 for the idea.

Td

Edited March 3, 20179 yr by wtdash

dude, nice hit!  i have put 60,000+ miles on my EGR vehicle with non-EGR engine, when reset the light comes back on within 30 miles so with 2000 miles on it this looks like you slam dunked it!

well done for doing it and well done for posting detailed description.

 

looks like one could cut the EGR pipe close to the valve and slide/clamp hose to it?

Edited April 18, 201312 yr by grossgary

dude, nice hit! i have put 60,000+ miles on my EGR vehicle with non-EGR engine, when reset the light comes back on within 30 miles so with 2000 miles on it this looks like you slam dunked it!

well done for doing it and well done for posting detailed description.

 

looks like one could cut the EGR pipe close to the valve and slide/clamp hose to it?

Thanks!

 

Yep...just cut it, loosen nut @ EGR Valve, swivel towards the IAC hose (if needed), tighten nut, clamp a hose on it, and T into the IAC. Eliminates the need for the 'fancy' fitting and saves a few $$.

 

TD

Edited April 18, 201312 yr by wtdash

that is amazingly simple - if i had an EGR intake manifold i'd do it...unfortunately i swapped mine to non-EGR intake....

 

i have a non-EGR intake, non-EGR ECU, clipped the ECU EGR wire(s)...and still have check engine lights...must be some wonky wiring on the body side or input via the auto trans or something.

the number of potential ej22s to swap into ej25 cars just doubled.

 

thanks for the pics and the write up.

 

well done.

 

sad that it ihas taken this long to find a solution.

but exciting that there is a solution.

EJ-18's too. Not that anyone would really want to swap in an Impreza EJ18 into an EJ25 car, but it'll get a car back on the road if the EJ22 supply dries up.

EJ-18's too. Not that anyone would really want to swap in an Impreza EJ18 into an EJ25 car, but it'll get a car back on the road if the EJ22 supply dries up.

Thanks...added to original post.

i think all ej18s have EGR.

i think all ej18s have EGR.

Not all but most. I was at a junkyard and spotted a really clean engine. No EGR which was a no-go for my swap, but I also checked the data plate and it was an EJ18.. 5spd car, '95 or '96 Impreza IIRC.

Edited April 22, 201312 yr by matt167

And the SOHC intake manifolds (IM) are all interchangeable from the EJ18 and EJ22, AFAIK.

 

Another point...I wonder if the EJ18's EGR is the same as the EJ22's? The EJ18 were mostly OBD1 and the EJ22 EGR are ALL OBD2/OBDII, and the the OBD2 ECU's may not like the older OBD1's EGR sensor/wiring/etc.

 

 

Anyone know?

 

Edit: My 'info-gathering' suggests that the '96+ OBD2 EJ18's did NOT have EGR as they were only used w/the 5-speed transmission -just like (most) EJ22's. There are NO OBD2 EJ18 Intake Manifolds w/EGR thru the '97 model year.

Td

Edited March 3, 20179 yr by wtdash

the IM on the 95 ej18 is taller than the one on the ej22 (it is also obd1), and therefore the EGR pipe is longer.

 

i'm not not 100% about the ej22 wiring on the ej18 IM. the obd1 / 2 line may be a defining differnce.

i know the IM will swap, i have done that. but i'm not sure the TPS is the same and so i don't know if the connector will swap.

ej18s, 93 - 95 at least, do not have a knock sensor, so that wiring is not usable in a swap.

 

but if the 97 ej18 IM is compatable this would be another source for an EGR intake.

better check that out.

Edited April 22, 201312 yr by johnceggleston

The TB/TPS and the Idle control valve is different between the EJ18 and the EJ22/25 at least for a 1996 Impreza ( just checked on Rockauto ).. Other thing is the ports on the EJ18 heads are smaller, so using an EJ18 EGR manifold on an EJ22 will reduce port flow.

 

As long as the Throttle Bodies swap, should be able to put an EJ25D wiring harness on an EJ18 manifold ontop of an EJ22E of any year ( correct sensors added of course ) and have it run correctly, minus the port flow issue that could possibly nix 10hp or better.. That would be a heck of a frankenmotor tho.

Edited April 22, 201312 yr by matt167

Another point if someone has to do an ej18 swap with the wiring change is that the ej18 block still has the threaded hole to instal a knock sensor into.

The TB/TPS and the Idle control valve is different between the EJ18 and the EJ22/25 at least for a 1996 Impreza ( just checked on Rockauto ).. Other thing is the ports on the EJ18 heads are smaller, so using an EJ18 EGR manifold on an EJ22 will reduce port flow.

 

As long as the Throttle Bodies swap, should be able to put an EJ25D wiring harness on an EJ18 manifold ontop of an EJ22E of any year ( correct sensors added of course ) and have it run correctly, minus the port flow issue that could possibly nix 10hp or better.. That would be a heck of a frankenmotor tho.

 

The ports on EJ18 and EJ22 heads are identical.  So are the valves.  Quench volume of the chamber may be a hair different, but it's not even visible really so it's a small difference.

 

It's a myth that they are smaller.

U is if you can use a '95+ OBD2 EJ22 engine wiring harness on an EJ18 EGR-equipped IM? 

 

I've never personally done any work/swaps on an EJ18 - EGR or not - so no idea.

 

Td

 

yes, i did it years ago to the legacy LSi in my sig and it's far easier than swapping wiring harnesses.

simply bolt the EJ22 intake manifold right on top of the EJ18 and install a knock sensor, done.

the EJ18 manifolds are ugly and convoluted anyway.

 

some have an exhaust port i think on the passengers side head that needs covered up but that's cake and takes 5 minutes for someone doing an engine swap.