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05micablue
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Alright. So I've been looking at this issue and searched the forum for hours last night to no avail.

 

Hello all, I just bought a 2005 Legacy GT.

 

So. Here's what happens.

 

Driving along keeping it out of boost, it drives fine. Idles fine. Runs a tad rich, which im guessing is from the Cobb intake that was put in, knowing the car has a MAP sensor. It was already modified. (Has an aftermarket boost guage and mufflers as well, I couldnt find anything else.)

 

Under WOT, it seems to have inconsistent boost. My gauge shows between 7 to 11-12 psi. I'll pull once and pull 7, and I'll pull again and get 11-12. Odd. Also feels like power wavers a bit during accel. Now here's the fun part.

 

Under WOT, once I rev to 5k, it falls on it's face. Revs to redline when parked and not really making boost. It stops accelerating at 5k, and starts making a tick tick tick sound. Stayed in it last night and got a flashing CEL for about 30 seconds, then it shut off.

 

Am I dealing with timing? Boost leak? Some alien magic? I'm new to the subaru world and turbo cars, so excuse my buffoonery.

 

Thanks guys. Happy Saturday

 

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Essential diagnostic equipment:

- OBDLink Bluetooth dongle and BtSsm Android app (alternatively VAG-COM cable and FreeSSM Windows app)

- Smoke machine ($65 on eBay)

 

Diagnostic tasks:

- Find out full list of mods

- Find out type of tune

- Use SSM to view fuel trims, timing pulls, misfires, etc.

- Smoke test intake & boost control hoses

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Essential diagnostic equipment:

- OBDLink Bluetooth dongle and BtSsm Android app (alternatively VAG-COM cable and FreeSSM Windows app)

- Smoke machine ($65 on eBay)

 

Diagnostic tasks:

- Find out full list of mods

- Find out type of tune

- Use SSM to view fuel trims, timing pulls, misfires, etc.

- Smoke test intake & boost control hoses

No tune that I know of.

 

Injen catback exhaust

 

Cobb SF intake.

 

So, I'm leaning more and more towards a boost leak. The car has 183k miles on it. Doesn't leak fluids. Doesn't smoke.

 

Mat it, takes a second to come on boost. Sometimes I get wastegate pressure, sometimes I get 10psi, but the power seems to come and go. Like for a split second the boost pull is there and it's gone the next.

 

Will not rev past 5 grand in gear, or it knocks (ticking and cel flash)

 

I'm going to look at the piping when I come home on Wednesday. Maybe try and spot a leak.

 

Kind of running on a budget and really didn't know what I was getting myself into, also pretty much desperate for a car at the time.

 

Sorry for any regurgitation.

 

 

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Either a boost control leak or a boost leak can cause those symptoms. So can other boost control problems, torn inlet, etc.

Ask around if a buddy can loan you a smoke machine.

Running that intake on a stock tune is no bueno and can damage your engine. Best bet is pick up a stock intake for $25 from a boneyard. The aftermarket intake gains you nothing but noise and an overly lean mixture.

A VAG-COM cable is $10 on eBay.

If you are unable or unwilling to spend the price of a tank of gas on the tools essential to repairing and maintaining this finicky, gas-guzzling, high-performance machine, you would be well advised to sell it and buy a Civic. A porly-maintained LGT will get really expensive, really fast.

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Just re-read the first post; a few notes.

- How did you determine the car is running rich?

- The MAF sensor, not the MAP sensor, is used to calculate the mixture.

- Tick-tick-tick sounds and flashing CELs at WOT are no joke.

- Cars with boost gauges rarely have no other significant mods. You would be well advised to have a buddy who knows these cars take a good look around.

 

If you want this car still running 1000 miles from now, be smart and stay out of boost till you properly diagnose and repair these problems.

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I'm very willing to fix! Let me say that right now.

 

Yes, I'm staying out of boost. I do NOT WANT to blow this motor up. I'd rather spend a few hundred bucks finding a boost leak than a few thousand replacing a motor.

 

I had the same idea as you as far as getting a stock intake for the car. Super cheap, and I can always re-install the Cobb intake later.

 

I bet some kid owned this who thought it was "fast" and ended up blowing a turbo line somewhere and then sold because he didn't know how to fix it.

 

I'm going to look into this stuff in the next week or two, stay out of boost, be nice to it, all that good stuff.

 

Thanks for the information!

 

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Smelling rich can be a mixture problem (SSM will tell you more) or a cat problem. If you're certain it has the stock downpipe, there's still the possibility it's been gutted. Of course, if there is a cat issue but no P0420, then the tune is not stock.
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The boost issue sounds like limp mode to me. Since you have a 2005, buy a VAG-COM cable on eBay and get LearningView (look in the tuning forum).

 

Check your spark plugs for signs of cracking on the porcelain (in reference to the the 5k rpm and flashing CEL). I had an issue where the cracked porcelain caused an intermittent misfire.

 

A stock car will not smell of exhaust. Did you pass emissions with OBD-II scan or an actual tailpipe emissions check?

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VAG-COM will be ordered on Thursday!

 

It passed emissions with OBDII scan.

 

I will go ahead and do plugs when I get back. Cheap insurance.

 

I'm just confused why I didn't get a CEL if it's misfiring.

 

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I will go ahead and do plugs when I get back. Cheap insurance.

Don't start firing the parts cannon with zero diagnosis. There is as yet nothing to point to the spark plugs, and for all you know they could have been replaced right before you bought the car.

 

For the price of a set of spark plugs, you can get a smoke machine and do some actual problem solving.

Edited by relative4
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Is there a table I can look at to see what the normal values are so I can find issues with VAG-COM?

 

Really appreciate the help guys.

 

Gonna get this ironed out hopefully in the next short while.

 

I'll report back with any issues I may have

 

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Alright. Dumb question because I can't leave it alone.

 

Since there is a Cobb SF intake on this thing, shouldn't I be checking to see if it has a tune flashed to it?

 

If not, should I flash a stage 1 before checking for boost leaks? See how it runs, go from there?

 

Thanks

 

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If you have an AccessPort, then you should absolutely flash a Stg1 tune that accounts for the SF intake (if I remember correctly, Cobb still carries a Stg1 + SF tune for the '05-'06 LGT).

 

These cars are _very_ tune sensitive. The wrong tune will easily kill your motor outside of closed-loop, and logging will help you much more with diagnosis than just performing tests or throwing parts/money at it. But there's a decent amount of time/effort required to learn how to log and what to look for that most people aren't interested in.

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Don't touch tuning until you can source the issue. Use LearningView to diagnose your using your AF learning table.

 

DO NOT RESET THE ECU during the troubleshooting process. Any codes or learning will be stored. A reset will clear everything and you'll be back to square 1.

 

That being said, the Cobb intake has been known to cause headaches. If you don't have an AccessPort, I recommend going open source tune (RomRaider) using the VAG-COM cable. There are several tuners that can get you tuned for less than an AP.

Edited by compsurge
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Alright folks. Enough speculation. I have some information for you.

 

I have some codes!

 

Also the top mount is leaking around the bottom passenger side corner.

 

Going to replace plugs, and change the intercooler, and also check fuel pressure to make sure everything is alright. ff503eff2739c977275e55d3f9cb5a2d.jpg

 

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