meier motor sports Posted June 13, 2012 Share Posted June 13, 2012 so you bent up a spark plug and think its a vacuum leak? never seen a vacuum bend the electrode of a spark plug. usually it has to bang on something Link to comment Share on other sites More sharing options...
Lardo420 Posted June 13, 2012 Share Posted June 13, 2012 so much vacuum that it bent the electrode. like -400psi vacuum Link to comment Share on other sites More sharing options...
bmx045 Posted June 13, 2012 Share Posted June 13, 2012 spec b combustion can sometimes blow the plugs right out of the head Link to comment Share on other sites More sharing options...
specialB Posted June 13, 2012 Author Share Posted June 13, 2012 OK, updates!! So I stopped at auto zone to pick up my leak down tester...which didn't turn out to be a leak down tester at all but a compression guage. Love when incompetent people work at auto part stores, I even asked him if the tool had two gauges and a regulator on it and he said yes. So, without any other options I grabbed the compression tester and headed to Subaru to pick up my plugs. Get home and pull all the plugs and go about trying to test my compression. Tester turned out to be a piece of garbage all together as it did not have an O-ring where the male end connects to the spark plug hole. A shitty seal left me reading 60psi on one of the non issue cylinders. So, unhappily I put it all back together with new plugs and made sure they were gapped right. Not so much voila, but it is definitely MUCH better. At first startup the idle was smooth no issue and no hiccups revving in neutral when before it was popping and backfiring like crazy. Took it down the block and it stalled at the first stop sign. From then on the idle was rough whenever i'd come to a stop and then it would come back up to normal after about 5-10 seconds. After warmed up I tried getting some power down and that was non issue, car pulled strong and hard like usual, only thing I noticed was downshifting I would get a little hesitation trying to rev match. Car didn't throw any codes the whole time I had it out and it didn't read any roughness in cylinder three. I did notice however that she was not hitting target boost. Where she was supposed to be touching twenty it never rose much over 17.1psi. I'm beginning to get a feeling I have a vacuum leak somewhere, maybe melted a hose or something that afternoon or idk what. Working on getting a good and proper leak down tester so I can rule out any issue with the rings or valves in cylinder three. Go back and read people please. I want to believe the bent plug is due to bad detonation and a history of several misfires on that cylinder slowly ruining the plug. I'm thinking there is a vacuum leak now on top of this as last time I had one I was experiencing the same rough and fluctuating idle and random hesitation without throwing any codes. Link to comment Share on other sites More sharing options...
bmx045 Posted June 13, 2012 Share Posted June 13, 2012 bro. that spark plug doesn't lie. something physically hit it, and it happened when you were dogging it with that X5 Link to comment Share on other sites More sharing options...
specialB Posted June 13, 2012 Author Share Posted June 13, 2012 i'm just baffled as to what. There was no loud pop or anything when it happened car just started shaking. 100% the piston did not hit it, and the plug isn't getting any oil on it so I can believe (not fully) that the rings are fine, but maybe a piece of valve broke of like you said bmx but only a leak down will confirm that without pulling apart the motor Link to comment Share on other sites More sharing options...
bmx045 Posted June 13, 2012 Share Posted June 13, 2012 when my plug bent i heard nothing as well, just a CEL and shaking car. priorities for you would be leakdown test, do you still have a cat in the up pipe? Link to comment Share on other sites More sharing options...
specialB Posted June 13, 2012 Author Share Posted June 13, 2012 Catless uppipe Link to comment Share on other sites More sharing options...
bmx045 Posted June 13, 2012 Share Posted June 13, 2012 bizarre. it had to have been something of good size. look at the chunk missing of my piston then look at my plug, then look at your plug. Link to comment Share on other sites More sharing options...
specialB Posted June 13, 2012 Author Share Posted June 13, 2012 I wish I had a picture off my piston I could upload but it loss nothing like that and your plug was barely touched. Maybe when I leak down I'll put the piston at BDC and scope it again Link to comment Share on other sites More sharing options...
specialB Posted June 13, 2012 Author Share Posted June 13, 2012 http://i3.photobucket.com/albums/y89/Max00racer/2012-06-13_17-39-24_747.jpg Link to comment Share on other sites More sharing options...
specialB Posted June 14, 2012 Author Share Posted June 14, 2012 Got the tester hooked up and this is what it read: http://i3.photobucket.com/albums/y89/Max00racer/2012-06-13_18-37-37_807.jpg I think this is a decent reading. I also did a compression test on both cylinders. The issue cylinder read 135-140 and the non issue one read 145. Managed to take a picture of the boroscope image: http://i3.photobucket.com/albums/y89/Max00racer/2012-06-13_18-24-06_375.jpg Only thing I see is carbon on the cylinder. The rings look shiny and ok. I reset the ECU like seven times testing compression because every tine you do the car doesn't start right away allowing me to crank the motor without it starting. Put it all back together and the car is now running fine...go figure. Waiting to run into more hesitation. Have to take a good hour drive tomorrow see if all stays well. Link to comment Share on other sites More sharing options...
Spec B Posted June 14, 2012 Share Posted June 14, 2012 what are those 2 black pointy-ish things on the boroscope photo? Looks like they are peeling off the edge.. Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 Those are called the piston valve reliefs. They are cast with the piston. Atleast as far as i can see with the poor pic quality. OP. did you manually crank over the crankshaft with your hand like you were suppose to for the leakdown? Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 Its difficult to see where the border of the piston crown is in that pic, sometimes the reflection off the cyl wall plays tricks with the eyes Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 And FWIW. You shouldnt be able to see the rings when looking down at a piston if you do, youre missing the top ringland, like i was. Link to comment Share on other sites More sharing options...
specialB Posted June 14, 2012 Author Share Posted June 14, 2012 Their the cut outs for the valves everyones pistons have that Link to comment Share on other sites More sharing options...
specialB Posted June 14, 2012 Author Share Posted June 14, 2012 Those are called the piston valve reliefs. They are cast with the piston. Atleast as far as i can see with the poor pic quality. OP. did you manually crank over the crankshaft with your hand like you were suppose to for the leakdown? Yessir I did, used a piece of heavy gauge wire end felt when it was at TDC and I believe it was on the compression stroke because if the exhaust valve was open if believe it would be flowing more. Maybe it is the walls making a reflection where i'm seeing something shiny around the edges. What was your leak down with no ringland bmx? Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 You just crank the crankshaft with your hand and a 22mm socket until you see the other gauge creep up, you dont necessarily need to know TDC because technically your highest reading would be during that position. After i mangled the plug, i replaced the plug and the leakdown was only 10% loss. Drove fine for a week until i blew the lower lands(from the missing protection of the crown that was suppose to be there). I did not scope it. The shiny curve of the piston is alarming as id expect the entire piston circumference to be gunked and carboned. I cant really tell due to the pic quality. When you get a hot spot on the piston it will show a shiny circle or spot, and from there is where the piston can crack- this is from a lean spot that gets super super hot and destroys the anti det protective layer off the piston coating and breaks the silica strewn aluminum straight through. Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 My lean spot- http://i1240.photobucket.com/albums/gg489/bmx045/2f948c19.jpg Link to comment Share on other sites More sharing options...
specialB Posted June 14, 2012 Author Share Posted June 14, 2012 I have a nice long commute ahead of me tomorrow so maybe I'll scope it again tomorrow night now that the thing is running nicely. All that misfiring and studdering probably left a lot of unburnt fuel and residue in that cylinder. Link to comment Share on other sites More sharing options...
WhiskeyTango Posted June 14, 2012 Share Posted June 14, 2012 I have a nice long commute ahead of me tomorrow so maybe I'll scope it again tomorrow night now that the thing is running nicely. All that misfiring and studdering probably left a lot of unburnt fuel and residue in that cylinder. I wonder how the long commute is...i bet its longer when he is stranded on the side of the road Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 I'm still looking at that boroscope pic, im on the edge of whether or not that is a missing crown piece, i want to say it is, but the reflection off the cyl wall makes it tough. I think he's going through the identical thing i went through. look at the black border of the piston, then look at the lack of thickness of the shiny portion, i think the reflection is of the top compression ring shining back at the camera. the crown doesnt look as thick in that edge of the piston in comparison to the rest of it. i'll find moar pics of mine Link to comment Share on other sites More sharing options...
WhiskeyTango Posted June 14, 2012 Share Posted June 14, 2012 the engine is fucked plain and simple. Link to comment Share on other sites More sharing options...
bmx045 Posted June 14, 2012 Share Posted June 14, 2012 either that or the reflection is simply from a lean spot that burned away the dark layer off the piston. but the symptoms and series of events don't justify a simply lean spot burn-off. Link to comment Share on other sites More sharing options...
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