IAC problem?

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Tommio RS
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IAC problem?

Post by Tommio RS »

OK.

So my car has had this intermittent hick up when warming up for some time now.
Like 3 years.

No this hick up is constant every time i drive the car....

It will run leaner and leaner until that car is fully warmed up then it will run perfect.

No issues at all.

Prime example
viewtopic.php?f=19&t=53374&hilit=lean+idle

My car runs JUST like that!

He stated he swapped the intake for the ej20g manifold

I dont think there is any cross ref. for the OE part number 22650AA111

BUT maybe a jdm wrx/sti unit may work on the ej22t intake manifold?


I have replaced the following already:

MAF
CTS
02 sensor

my next step it buying a new iac......NOW this guy is not easy to change OR cheap to get.

Its extremely tight in that spot because of my GT28 turbo.....
I really dont want to pull the intake off.........

Any thoughts??

Tom
93 Legacy Turbo AT Sliver Stock, Ultra Rotty Body
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Legacy777
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Re: IAC problem?

Post by Legacy777 »

What engine management are you using?

Do you have a wide band O2 sensor? If so, what are your AFR's during warm up?

I think we need to try and separate poor warm-up performance and AFR's running lean. If the AFR's are where they should be then a new IAC valve may help your problem. If the AFR's are lean then changing the IAC valve probably won't make a difference.

What you could try is replacing just the top electromagnetic portion of the IAC valve. If you're running the stock ECU you can use Vikash's scan tool to set the IAC valve duty % in the normal range so it's calibrated properly.

The other thing you can try doing is unplugging the electrical connector on the IAC valve and see how the engine runs during warm up.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

Engine management is the Rob Tune ECM with the 550 tune on it.

I do have the AEM wide band 02. The sensor is located 2 feet down the down pipe.

Im NOT kidding when i tell ya this.

The car will run 12.8 to 13.8 AFR before the car enters closed loop.
When it hits close loop it will bounce from 13 to 20/ pinning my gauge.
The moment the car is finally warm the AFR is around 13 to 14 depending.
ALL these AFR's are at idle!

Its a clone of:

viewtopic.php?f=19&t=53374&hilit=lean+idle

I replaced the factory 02 sensor and that made my AFR at idle while warming up bounce from 14.8 to 15.8 AFR.
My old factory 02 was dented and had rattling bits in it!
Was totally shot.

Now i replaced the factory 02 because when i unplugged it from the car, it warmed up perfect! rock solid AFR.
About 12.8 to 13.8ish.

Thats why i swapped out the factory 02 for a new 02.

Now i have this bouncy idle AFR with poor throttle response.....Like before but with better AFR

ALSO if i could scan my ROB Tune ECM with a scan tool i would NOT be in this pickle.......

I have all the OEM scan tools subaru has ever made and none will work. I know that.....That has been discussed in another thread i made.

It just sucks when you have such a nice clean car and its not running right.....
I feel ashamed driving the car when its in this state. Its TOO dam mint for this!

I have a lead for a used idle air control valve for $150
I also have a lead for a NEW oem unit for $340 all in........

I have swapped many a IACV on 95-99 legacy and outback because they were know for poor idle and such.

Also to swap the IACV on a EJ22T looks to be not fun.....
I dont want to remove the intake mani if i dont have to.
I do have a sea of swivel cheater sockets of the micro variety.

I really dont know.

Thoughts???
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Re: IAC problem?

Post by Legacy777 »

Hmmmm

So what happens if you just unplug the stock O2 sensor completely and run without it? I believe you said it warms up normally and everything is fine; is that correct?

If that is correct you've got something going on with the O2 sensor and/or how the ECU is interpreting the O2 sensor data. Are you running a 3 or 4 wire O2 sensor? Do you have anything surrounding the stock O2 sensor? Is it in the stock location just after the turbo? Have you checked continuity between the engine block and body of the O2 sensor, as well as between the negative lead of the battery and engine block and O2 sensor body? Have you checked all the wiring from the ECU to the O2 sensor?

The first thing I'd do is rule out a wiring problem with the O2 sensor wiring, including the heater circuit. With the 3-wire sensors the sensor grounds through the body and exhaust system. If that is not a good ground that could be throwing things off. 4-wire sensors have a specific sensor ground which can be wired up to a good separate ground if needed.

That's what I'd try.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

Ok.

Well i know the 02 is a 3 wire, so it does not have the heater circuit in it.
I have a custom made stainless steel heat shield that does NOT touch the 02 sensors body.
02 sensor is in stock location up by the turbo, just straight up not sideways.


In terms of grounds to the 02.....
There could be a wiring issue at the sensor, maybe. will have to check on that.
Ground going to the engine are all stock other than one that i added on the intake manifold on cylinder 4.
My exhausts only points that touch metal at all are on the transmission and the turbo itself.
My exhaust also has NO flex joint or wax donut behind the transmission........I have been wanting to fix that for years!

Also to note.

I do have group N motor mounts, and that makes the car vibration much MUCH more!
Know that i think of that.....It seems to have gotten worst since i swapped those mounts in?


Im going to start with the basics for the 02 sensor wiring i guess for now.
I cant start the car currently also. I have my AWIC getting powder coated this next week.
Should have much time to scope out the 02 by then!
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Re: IAC problem?

Post by Legacy777 »

Some comments:

The 3-wire O2 does have a heater circuit. One wire is for the sensor, one wire is the positive lead for the heater, and one wire is the ground lead for the heater.

For 4-wire O2 sensors it has all the wires that the 3-wire has, but has one more wire where the sensor grounds through vs. grounding through the O2 sensor body.

Do check for continuity between the downpipe and engine and negative post of the battery. The exhaust should ground through the engine since the exhaust studs touch the headers. However if things are very rusty that ground may not be very good.

I've got full group N mounts on the engine & trans. It's possible if there's a bad ground or loose wire the added vibration could make things worse.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

Ok.

So i have checked continuity from my down pipe to my battery ground terminal. I have 1.2ohms.

I disconnected the 02 sensor from the wiring loom and checked the black white wire for continuity, which i did.

I tested continuity between the black white wire and all other wires on the 02 sensor loom.
I have not continuity between any other wires......?
I know one of them is signal the other should be a power of sorts.
Looks like a white red wire and just a plain white wire. cant find a stripe on that one....

Am i to have continuity between any other of those wires??

Also i did a continuity test also on the wires in the same manner with the key on. I KNOW to not do that!
I did it any ways just because.

I think i might start to dig up what voltages i should be seeing on these wires.

Thanks

Tom
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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

Ok.

So i performed the same continuity tests on my other stock 1993 legacy ss.

It has the same exact results of continuity, and that car runs mint. for a stocker.

So that leads me some where i guess.....

Back to checking other things.
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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

OK.

Im starting to rule out the 02 sensor.
everything looks to be OK on that section.

Now could a faulty 22012aa020 sensor assembly vacuum/ Sorta MAP senor cause this poor idle condition??

It now idles at 14.6-15.8 AFR all the time after warm up, does not go away.......
It now also when just cruising at any speed in any gear with have the same AFR 14.6-15.8 or higher!

I grow scared of it.

BUT if you give it some beans/boost, the AFR is drop into the 12 area.

And NO. I have NOT FLOORED IT!!!! Just enough to get some boost.

Also an odd little side note:

This motor was swapped out of my test mule rusty legacy which did this same odd idle dancer before.
My rusted mule car has a near minty 55k motor in her and its perfect.
So im leaning towards that some sensor on the motor that i swapped into my good leggy is pooched.
Wild guesses.....Idle air control or TPS or some atmospheric deal.

ALSO. If i disconnect lets say the maf sensor, what sensors is the car using to stay running? same with the 02 or tps or iac????
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Re: IAC problem?

Post by Tommio RS »

OK.

More testing have been done.

The info:

With 02 sensor unplugged.

Unplugging the 02 sensor seems to make the car run MUCH less lean.
The car does not bounce into the 15's AFR like this when cruising.

The car still will some times have a "hiccup" when you get out of boost for a bit.
It will run mega lean then slowly scale back into a more safe zone.

Some times when the car is warming up it will idle a bit funny and run sorta lean like
15's AFR


With the new 02 sensor plugged in:

Runs lean all the time other than when in boost.
It basically changes map's and does NOT care about things.

The more info:

Tested ALL 02 sensor wiring on the car.
I have signal at the ECM and at the 02 sensor.
I have source power at the 02 sensor 12+V.
I have ground every where i try at the 02 sensor.

Deductive reasoning leads me to one part.
The Idle air control valve.

So im going to get a new IACV soon.....

Will keep you peoples updated.


Two concerns regarding the IACV
Does the IACV do ANYTHING at off idle cruising speeds?
Does the IACV become"less" effective when the car is in open loop/02 sensor unplugged???

Notes about the discoveries:

From what i see about the 02 sensor reading and data i have found,
the 02 sensor and circuit i working 100%
The car is actually trying to compensate for an air fuel ratio error.
The only thing i can see that could cause an inconsistent AFR is the IACV.

Sorry for the long winded explanation...

Tom
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Re: IAC problem?

Post by Legacy777 »

Tom,

Sorry for my MIA status.

Did you end up swapping the IAC valve, and if so did it help?
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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Tommio RS
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Re: IAC problem?

Post by Tommio RS »

Legacy777 yes I have JUST swapped out the IACV.

I could NOT find a good used or new IACV for a ej22t so i had to find some other replacement.

I ended up finding a guy who was parting out a ton of JDM cars like wrx/sti's/twin turbo legacy's.

I risked it all with a 22650aa132 IACV.

looks like this:

http://auctions.c.yimg.jp/images.auctio ... 830344.jpg

Of coarse its bolts to the intake manifold BUT 2 of the 3 hoses/connections are in the wrong spot.

So i just got longer hoses and such to make it work.

Also the electrical connector is facing the intake now. Making it impossible to unclip the connector.

So how does it work you thinks????

I took it for a ride and all seems well so far.

I think my long term fuel trim is going to take some time to smooth out but on the hole, MUCH better idle and cruising AFR's.

I will take a picture of the sorta ghetto rigging for the valve install.

Will keep posted on this because this problem is just MADNESS to repair and fix and diag.


NOTES on removing the IACV:

I NEVER removed the intake manifold from my car.
I used mainly just my snap-on cheater swivel 10mm socket to do most of this job.
I would recommend that you remove the intake OR if your car is stock you might be able to do this.
It took me about 3 or so hours of pure fighting to remove the pig..... And working on cars IS my job!
Also my best guess, as long as your subaru of any year uses this shutter door style IACV and you can bolt it onto your intake manifold, you can use it.
Your hook ups look to be all wrong but if you ghetto rig them, it should work!
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Re: IAC problem?

Post by Legacy777 »

Glad to hear it's running better. I'd recommend resetting the ECU to clear all the long-term fuel trims.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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If you need to get a hold of me please email me rather then pm
Tommio RS
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Re: IAC problem?

Post by Tommio RS »

OK.

Sort of update.

So the car does idle OK I think basically all the time now which is good!
I see anywhere from 12ish to 14.2 AFR now.

But now I still have this lean cruising AFR.....

It keeps bouncing around running lean all the time when warm.....making the car run way WAY to hot.......

I have a video of how it used to idle right here:

https://www.youtube.com/watch?v=Du29iyMwucQ

If you notice at the 1:26 mark an on, the AFR goes from like 14.6-15.7ish

This is the EXACT dance it does when cruising. Its hard to film this when driving. So i posted this video instead.

Notes about the video:

The car is dead cold 1st start of the day.
I never touch the gas at all in the video.
This is before my IACV install
The car does NOT idle like this anymore.
The car cruises like this now!
The car cruised like this before I installed the IACV.



How to get car to cruise poorly/NOTES:

Drive car until warm
AFR when cruising get higher and higher until hot
Need to be in 3rd gear or higher and over 2000 rpm
A speed over 40km
Unplugging the 02 sensor drops the AFR's into the 12's and 13's AFR, so safe

Picture of the IACV install:

Image


I have removed the TPS from the car.
It makes some bad sounds when turning the TPS
It creaks and squeaks and might rattle a bit.......
If I work the throttle linkage with the TPS in, it sound bad.
If I work the throttle linkage with out the TPS in, no noises
I think the TPS sensor is dead also........OR has a dead stop

Any thoughts?

Tom
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Re: IAC problem?

Post by Legacy777 »

Tom,

My first suggestion is if you know or have a pretty good idea you have a bad component (TPS) you need to fix that. Trying to do any troubleshooting until that is fixed is pointless and futile. Have you run though the TPS diagnostic test in the FSM? If not, do that. See if you can find a used TPS (non-turbo & turbo are the same) and calibrate it per these instructions.

http://main.experiencetherave.com/subar ... sting3.jpg

Reset the ECU to clear learned fuel trims and see if the problem persists.
Josh

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Re: IAC problem?

Post by Tommio RS »

Ok Legacy777. I will try the ecu reset and perform the full TPS diag. and calibration this weekend.

Just need to bring home my multi meter and feeler gauge set to start.

Will report back again with findings.

Tom.
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Re: IAC problem?

Post by Tommio RS »

OK.

Performed the TPS calibration the best i could.
All the feeler gauge numbers see to be with in spec.

I swapped the TPS from my beater to my good car.
Still runs the same........

I noticed when i removed my turbo inlet pipe, you know the one that cracks all the time.
It was cracked!
So i replaced it with a NEW one!

Image

Here are some crappy videos i made on my cell phone of exactly what it does:

Video one is me driving at 40mph and the AFR is bouncing all over the joint......
car is HOT at this point. Ignore most of the video after 10 seconds.
https://www.youtube.com/watch?v=WsAWBdIuotc

Video two is after the same drive and the car is idling in my garage.
AFR is lean then drops to mad rich to compensate.
https://www.youtube.com/watch?v=BIMzHaaKc-E

NOTE:
This odd AFR dance really only happens IF i have been driving for a long time and she is HOT
or
I give it some good beans and push some boost.
Then it will dance.......

Thoughts????
This is driving me insane by the way.
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Re: IAC problem?

Post by Legacy777 »

Hmmm

Honestly, I have my suspicion it's ECU related. Or at least I'd see what I can do to eliminate it as a possible source of the problem. At this point I think you just need to check every sensor against what the FSM states as well as all the wiring from the sensors to the ECU. Also check the engine/ECU ground and make sure you don't have a ground differential. If you do (or have done) all of that and still have the issue then I'd really start leaning towards the ECU, or at least trying to rule it out as a possible cause.
Josh

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Re: IAC problem?

Post by Legacy777 »

Also, in your second video what is that thing to the left and down of the steering wheel with the green up arrow and white number 19?
Josh

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Re: IAC problem?

Post by Tommio RS »

Thanks legacy777 for the fast reply!
The device on the left of my steering wheel is my GFB electronic boost controller.

I'm going to now for sure do a full system wiring check and and ecm wiring check/inspection!

If all else fails.....Haltech is in order...... sorry Rob Tune.
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Re: IAC problem?

Post by Legacy777 »

Yeah, the wiring is very important and is why I did a full check on all my wiring before doing my stand alone so I wasn't chasing phantom issues.

Keep us posted
Josh

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Re: IAC problem?

Post by Tommio RS »

Have not checked out my wiring yet due to too much other work, BUT this hit me like a TON of bricks!

My turbo flows too much air.
Its sounds stupid i know.

Just hear me out.

I have the Rob Tune 550 tune/ yellow top injectors.
Im suppose to have the TD05 turbo or something like that.
I have the mythic Garrett GT2860RS on my car.


Some turbo tide bites on CFM:

JDM TD05 505 cfm
Turbo info found:
http://bbs.legacycentral.org/viewtopic.php?f=2&t=52682

Garrett GT28060RS 500-600cfm
https://www.turbobygarrett.com/turbobyg ... r#GT2860RS
My exact turbo but subaru modded.
Unable to find a real good source of CFM.
Also dont know how to calculate CFMs.



So what does this all mean.

My car is set currently for 18psi of boost.
Im going to set the boost to 14psi about and see if that fixes the problem.

The problem really only happens when i beans it anyways.....

End result of this post.

Turbo makes too much air flow at higher boost number causing the green label MAF to max out, causing lean issues.

Turning down boost and reporting back ASAP!

Tom
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Re: IAC problem?

Post by Legacy777 »

I agree with that assessment for the high boost situation. It shouldn't really be an issue for idle or lower flow issues.

You can hook up a multimeter to the MAF signal & ground leads at the ECU to watch the MAF voltage and if it peaks at or around 5v then yup, you've likely found your problem.
Josh

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Re: IAC problem?

Post by Tommio RS »

Well......
After much testing and part replacement.....

I think my ecu/ tune on the ecu is messed up.

I swapped 3 MAF sensors
one had 20km
one had 130km
one had well over 200km

Car ran the same on ALL the MAF sensors

I checked voltage on my MAF wires including the signal
Every thing "seemed" ok just jumpy.

I replaced my fuel filter, thermostat and spark plugs ard re gaped them to .28.

None of those parts "looked" off from my eye.

I personally just think the Rob Tuned ECU is trying to compensate for something thats not there.
OR
My car seems to just runs perfect?

I have the cars 02 sensor currently unplugged and totally removed from the car and stuck a bung in place of it.

The car seems to run better in open loop by a little bit.

When the car DOES have the 02 plugged in, it has the odd lean dance still but HOLY MAN!
It runs hard. like REALLY HARD.
I think that's due to the fact that the cars running lean and on the edge of....You know.
I gave it FULL beans on once just to see.
Once you punched it, it went normal rich like.
BUT if you kept into it, it would creep into lean UNDER BOOST.........Not good.

Something is out of wack with the air flow meter and the ecu.


So....Im sad now.

I have found an odd cross road i would have never thought i would cross in my build, but here i am.

Which leads me to this.

Stand Alone ecu's

I have narrowed it down to two companies:

Haltech Elite 1500 because knock control!
Simtek MY93-96 4 Plug....No one over seas has heard or seen this product BUT its plug and play!

I basically NEVER want to see another MAF on a higher performance car i own ever again.


I have on order this beautiful gem on a harness to make life easy already.

http://bbs.legacycentral.org/viewtopic.php?f=19&t=55345

In terms of tuning a stand alone ecu.
I have no real idea on tuning.
I Know how to pull the rom off my current rob tuned ecu. But i dont think that would help at all that much really.....
I would have gone stand alone years ago, but my city of Winnipeg BLOWS for anything AWD and JDM.

My final though as typing this up is to try the following on my car:

Install 02 sensor
Disconnect battery to clear memories
Drive car around and not all that hard/fast for a day or so.
See if ANY codes are on the ecu system by doing the CEL light dance. I dont have EVO scan or whatever.
Go from there really.

If nothing come out of that, Im buying a stand alone and just ending the entire problem.

Sorry for the late reply but things take time when ruling out issues.

Thanks for read if you made it this far.

Tom
93 Legacy Turbo AT Sliver Stock, Ultra Rotty Body
93 Legacy Turbo MT Silver Rob Tune 550cc Lowered GT28 AWIC 4.11 05 Leg GT rims Mint body
95 Chevy Corvette MT ZR-1 Black X Brace Chipped
94 Legacy Turbo AT Blue Stock SOLD
06 Pontiac G6 AT Green Stock SOLD
Legacy777
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Re: IAC problem?

Post by Legacy777 »

Tom,

I've been a bit more MIA than usual, but am glad I hopped on the BBS today.

Probably one of the biggest lessons I learned in regards to stand alones is that you really need to have local tuning support for the ECU you want to use. Most any tuner can setup fuel & timing tables, however when it comes to configuring the ECU and ECU's that have more advanced features the tuner really needs to know and understand how the ECU works or you will not get the most out of it. My car has gone to three different tuners, one in Houston, one in Dallas, and finally one in Santa Rosa, CA....and it's been out to Santa Rosa twice; the second time was after I rebuilt the motor.

So before you buy a stand alone I'd encourage you to reach out to local tuners or whoever you want/think you'd like to do the tuning and see what software/ECU's they use. If none use what you plan to get you almost need to get a commitment from them to learn the software or you just won't be happy with the results....I can almost guarantee that based on my experience. The alternative is to find a remote tuner that can work with you remotely and/or with sending logs back and forth and maybe even driving or shipping the car.

Going down the stand alone route is not a cheap or easy option, but can provide a lot more flexibility and control if you're willing to pay for it and have the time to invest.

I like your suggestion of going back to stock and see if any codes comes up. Also, I don't recall if you mentioned this before, but have you tried a different robtuned ECU?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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