Motor is back in, but I have an issue

[poconoracing]

2010 Legacy GT - 120k miles

 

Finished up my clutch repair today. What a PITA for a $10.52 clutch pivot ball. Clutch works fine. Since I had to bleed it anyway, I did the damper delete as well. Thank you for the pictorial reeg420!

 

Car idles fine. Drives fine as long as you drive sensibly. I did stretch her legs a bit after about 30 minutes of driving and it has an odd problem I can duplicate readily.

 

Approx 5500 RPM, Wide open throttle it falls on its face. It feels like its hitting a rev limiter. If you take it to the redline at half throttle it goes all the way to 6500, no issues. I'm thinking its a boost issue, since WOT would also be full boost.

 

No CEL, no residual driveabilty issue, Car seems completely fine otherwise.

 

I did a visual inspection and found one plug under the ABS module that is unplugged, but for the life of me I cannot find the other end. I'm hoping you guys might know where it goes.

 

Its on the passenger frame rail below the ABS module. I took a pic of the plug, as well as one a little father out to give you a sense of where it is.

 

Any help would be appreciated. I'm not sure this plug is related to the driveability issue, but either way I'd like to find it's mate.

[FLlegacy]

That plug has no mate on our cars, mine is tied up to the harness as well with nothing attached. It is probably for another trim line or the outback, or possibly a diagnostic connector.

[FLlegacy]

I would double check all the charge pipe fittings and the intercooler coupler, I would bet on a boost leak. Have you logged it to see what the AFRs look like?

[poconoracing]

That plug has no mate on our cars, mine is tied up to the harness as well with nothing attached. It is probably for another trim line or the outback, or possibly a diagnostic connector.

 

Figures. I spent 30 minutes looking for the other end!

 

Any thoughts on that driveability issue? It’s the weirdest thing. The only thing I did with the motor out was replace the plugs with ngk iridium. Same number as the plugs that were in it. I used your walkthrough and pulled the motor complete with the turbo and everything on it.

[poconoracing]

I would double check all the charge pipe fittings and the intercooler coupler, I would bet on a boost leak. Have you logged it to see what the AFRs look like?

 

Forgive me for sounding dumb, but the charge pipe is the black one that goes from the turbo up the passenger side to the intercooler, correct? Never had a turbocharged car before

 

I’ll check in the daylight again to make sure I got all those on square and the clamps are tight up to the throttle body. So you are thinking the boost may be pushing past the fittings once it gets up to 11 or 12 psi? The car is stock.

 

If that’s not it, check and see if the upstream o2 is going way rich when it happens?

Edited October 9, 2019 by poconoracing

[DrD123]

There are a lot of reports of counterfeit NGK plugs (they even have a page on their website on how to identify) - ebay and amazon have a lot of them - any chance there's an issue with the plugs?

[Fabsx]

That plug I believe is for the puddle lights under the skirts. If your legacy wasn’t equipped with it, that’s the plug.

And when it falls on it’s face, does the check engine pop up?

 

 

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[stewdogg]

Yeah, I feel like if it was losing boost at full boost you would hear the blow off. I have lost charge pipes on my diesels at work and they make a big bang when they blow off.

 

Almost sounds like a fueling issue because of no check engine light.

I would think bad spark would throw the engine light or cause a misfire.

[FLlegacy]

Yeah, I feel like if it was losing boost at full boost you would hear the blow off. I have lost charge pipes on my diesels at work and they make a big bang when they blow off.

 

Almost sounds like a fueling issue because of no check engine light.

I would think bad spark would throw the engine light or cause a misfire.

 

The bang would only happen if the fitting came completely off been there and done that one, lol. Most likely the throttle body coupler is loose or one of the gaskets is coming loose and would produce a farting sound when leaking and probably hard to hear in the car, it is a common failure point.

[poconoracing]

Plugs came from AutoZone, not saying they don't have their fair share of junk but I doubt they are counterfeit.

 

I gave it a good listen and really all I hear is what sounds like 'thup' as it falls on its face. I did not hold it at WOT after it started acting up. When I let off the throttle it runs completely normally. It accelerates fine at half throttle all the way to the redline. No CEL set or flashing

 

I'll disconnect and reconnect all the hoses between the MAF and the throttle body that I disturbed. Maybe one isn't quite right.

 

Any tricks to making sure these are airtight?

[dgoodhue]

The connections to the turbo inlet and outlet have gaskets that may fallen out. Your issue is likely a simple reassembly mistake. Edited October 9, 2019 by dgoodhue

[stewdogg]

That intercooler coupler was all messed up on my car. There's a pic of it in my thread below.

https://legacygt.com/forums/showthread.php/stewdoggs-2010-gt-269205p14.html

 

I didn't reuse the hose on my car, but the gasket pulls right off and you can use the hose on it's own without the gasket installed. The gasket is one of those things that I don't understand why it's there other than to create a possible issue in the future.

[poconoracing]

These are the connections I disturbed. I didn't see any gaskets here outside of the band clamps. I also don't see any on the parts fiche.

 

Should there be?

[coco26]

The most common one to have problems is the short pipe that connects to the driver side of the intercooler. It's not what you'd think of when you hear "gasket", it's more of a rubber flap on the inside of the rubber tube. The idea is that it seals to the ridge on the intercooler, but in reality, it either folds into the tube (it loops around the end of the tube and is supposed to be held in place by the hose clamp) or it gets torn and doesn't seal.

[FLlegacy]

this thread will explain it.

 

https://legacygt.com/forums/showpost.php?p=3438271&postcount=37

[poconoracing]

The most common one to have problems is the short pipe that connects to the driver side of the intercooler. It's not what you'd think of when you hear "gasket", it's more of a rubber flap on the inside of the rubber tube. The idea is that it seals to the ridge on the intercooler, but in reality, it either folds into the tube (it loops around the end of the tube and is supposed to be held in place by the hose clamp) or it gets torn and doesn't seal.

 

I'll pull it back apart and see what I have. I'll report back with what I find

 

Thanks all!

[poconoracing]

 

Ok so I’m thinking I shouldn’t be seeing this little bit of rubber?

 

 

 

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[FLlegacy]

Pretty sure you've found your problem. Easy solution is take the coupler off and remove those end "gaskets" and then reinstall it.

 

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[poconoracing]

Pretty sure you've found your problem. Easy solution is take the coupler off and remove those end "gaskets" and then reinstall it.

 

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I’m pulling the intercooler out, and removing the clamp and sliding the rubber piece off the end of the coupler? Then what, just remove that rubber ‘gasket’ underneath? Or am I removing the whole rubber ring just leaving the band clamp right on the coupler?

 

It’s dark now so I’ll tackle this tomorrow after work.

 

Thanks again.

[stewdogg]

I’m pulling the intercooler out, and removing the clamp and sliding the rubber piece off the end of the coupler? Then what, just remove that rubber ‘gasket’ underneath? Or am I removing the whole rubber ring just leaving the band clamp right on the coupler?

 

It’s dark now so I’ll tackle this tomorrow after work.

 

Thanks again.

 

Just pull the intercooler coupler out of the car (the short hose from the intercooler to intake) and grab the end that the clamp is on and pull it away from the opening of the hose. It should pull right off. There is one on each side of the coupler hose and I would remove both. You can then reuse the clamp and coupler hose.

[poconoracing]

Ok so I got home late again and I had to get into it. It's bugging me

 

Pulled the IC off and pulled the seal. pretty straight forward. There does not appear to be anything wrong with it. Pics below

 

Left it out, buttoned it back up and took it for a spin.

 

Same thing. 3rd gear at about 5000 rpm WOT it started doing its thing.

 

This time I held it down and after about 3 seconds the dash lit up like a Christmas tree. Always amazes me how subaru has every light flashing for a check engine. Set a P0303.

 

So I have a direction. Motor is hot now so I'll let it cool and check that coil. I did pull them all to change the plugs. Maybe not quite on right. I cleaned the connectors with electronic parts cleaner and put a little die electric grease on them to keep the crusties out. The coils did have a bit of rust on the metal part which I used a brush and took off. I used a little black rustoleum on the metal to slow down the rust. I may have damaged the coil somehow. I'll check the connector and pull the plug. If its on right and the plug is ok. I guess I'm buying a coil.

[FLlegacy]

Coils are a common failure due to rust.

 

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[poconoracing]

All the coils had some rust on them. Surface rust. None of the heat sinks were swelled up, that’s what I was looking for.

 

What exactly does the rust cause to fail? I’m curious.

[dgoodhue]

All the coils had some rust on them. Surface rust. None of the heat sinks were swelled up, that’s what I was looking for.

 

What exactly does the rust cause to fail? I’m curious.

 

The heats sinks when they rust don't cool, so they overheat and fail (I assume the coil itself, but there maybe other electronics).

[cww516]

Before you buy a new coil, did you swap 1 and 3 to see if the problem follows the coil? Surface rust is fine, you'll usually see the layers starting to peel apart before you actually get to a failure condition.