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Old 01-26-2008, 01:35 PM   #1
drmx
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Member#: 95773
Join Date: Sep 2005
Chapter/Region: MAIC
Location: Carlisle, PA
Vehicle:
15 WRX WRB Base
90 300zx Twin Turbo

Default ring failure ?

Perhaps someone can confirm my theory. Car starts and runs fine, idles a bit high at first then smooths out. If I remove the oil cap when the engine is cold you can feel it pushing air out and it stalls after a few seconds. Once the engine warms up and cylinder tolerances are reduced - removing the oil cap doesn't cause a stall, but a lower/rougher idle and I can still feel it pushing air out.

I'm also having to add a 1/2 quart of oil every other week or so. I don't drive it much but always short distances so it rarely warms up fully. About every 5-10 starts it puffs a big smoke cloud like oil was sitting in the cylinder.

Does it make sense that the rings aren't sealing properly? I will be doing a compression test after work tonight and will edit with results.
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Last edited by drmx; 01-26-2008 at 02:01 PM.
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Old 01-26-2008, 02:40 PM   #2
flstffxe
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Member#: 155358
Join Date: Jul 2007
Location: Coon Rapids, MN
Vehicle:
2008 Forester
Steel Silver

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rings, valve seals, potentially even a cracked but not yet broken piston. part of it could also be a plugged pcv. compression test as mentioned also a leak down test would be good to do.
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Old 01-28-2008, 07:33 PM   #3
drmx
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Member#: 95773
Join Date: Sep 2005
Chapter/Region: MAIC
Location: Carlisle, PA
Vehicle:
15 WRX WRB Base
90 300zx Twin Turbo

Default

PCV valve seemed ok, rattled when I shook it, also swapped it out with another known good one and checked all its related hoses to the block for clogs...all clear.

Compression test results:
#1 - 220 #2 - 200
#3 - 210 #4 - 215

Cylinder 2 pushes a lot of air out of the plug hole when cranking and seems to make a loud whooshing noise with every pulse of air. None of the other cylinders seem to do this.

I'm pulling the intake manifold off now as I noticed there is oil leaking from the area of the cylinder 4 runner. The manifold was recently off to merge EGR wiring in after the swap to pass state emissions testing. I don't see how that would affect this problem but I can't say I recall this happening prior to that.
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Old 01-29-2008, 12:02 AM   #4
PhilSine
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Member#: 130489
Join Date: Oct 2006
Chapter/Region: MWSOC
Location: Superior, WI
Vehicle:
02 WRX Wagon (WRB)
98 OBS-T, 91 Legacy SS

Default

Are we talking the EJ18 or EJ22 engine here?

If its the EJ22 I'd redo my compression test if I were you as over 200 psi is quite high. According to my local mechanic, 185 psi is what you should expect from an EJ22 and that's a 98 EJ22 with 9.7:1 CR vs yours which is said to have 9.5:1 CR. One key thing is to do the compression test on a warm engine and with all spark plugs removed and at least the coil disconnected.

Plus or minus 10% across all cylinders is healthy regardless of what you're getting for readings so long as they're not dreadfully low.
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