04-19-2018, 06:24 AM | #1 |
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I have a misfire / spark plug issue
Hello all, it’s been a long time! Last week I started having an issue on my L99 with a very rough idle, misfires and backfiring. Yesterday I decided to pull the plugs and while the tips all seemed OK, the threads on 6 of the 8 had a lot of oil on them. See the attached picture. I’m guessing this is somehow my problem, however I’m not very mechanical. The car is six years old in November, but only has just under 13,000 miles.
Any suggestions here? What should I do or what should I be looking for? Someone mentioned to me it could be the valve cover gasket, however I don’t see any oil on the outside. And then someone also mentioned spark plug O-rings, however I can’t seem to find anything about them on the on l99. Thanks everyone and I look forward to the replies. Sent from my iPhone using Tapatalk Last edited by nyrfan; 04-19-2018 at 07:19 AM. |
04-19-2018, 09:21 AM | #2 |
Drives: 2015 Chevy Camaro 2LS Join Date: May 2017
Location: MWC, OK
Posts: 815
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hmm. looks odd that the electrode seems clean, but threads have wet oil, but not the terminal! were the 6 and 8 plugs seated properly? tight?
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04-19-2018, 09:44 AM | #3 |
Canadian
Drives: 2011 Camaro 2SS/RS Join Date: Dec 2013
Location: Lumsden Saskatchewan
Posts: 406
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Is there a leak from the valve cover by chance? And if not do you see any fluid from the exh. Manifolds at all?
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04-19-2018, 10:06 AM | #4 |
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Like I said only that the treads appear to be wet, but I’m assuming oil is getting onto the electrodes as I’m getting a lot of misfire and backfires. I see no oil anywhere around the valve covers or anywhere else for that matter, only in the treads. And yes they seemed pretty solidly in there.
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04-19-2018, 10:14 AM | #5 |
Canadian
Drives: 2011 Camaro 2SS/RS Join Date: Dec 2013
Location: Lumsden Saskatchewan
Posts: 406
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It could be possible blow by, it could also be the excess oil that is ingested through the pcv system that is routed back through the intake.
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2011 Camaro SS/RS
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04-19-2018, 11:53 AM | #6 |
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I don’t believe this would be blow by.
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04-19-2018, 12:12 PM | #7 |
Drives: 2014 2SS RS, 6 sp man Join Date: Feb 2016
Location: Marlton, NJ
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When you say backfire do you mean backfire into the intake manifold or an after fire in the exhaust? Backfire is usually caused by a lean condition or a valve stuck or damaged. After fire a rich condition such as lose of spark or overfuel. Weird about the oil only on the treads.
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04-19-2018, 12:26 PM | #8 |
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Any CEL? As there’s oil on both banks kind of rules out both VCs leaking. Have the vc, plugs, heads ever been out before? What’s the catch can look like?
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04-19-2018, 12:28 PM | #9 |
Drives: 2010 Camaro SS/RS Join Date: Mar 2014
Location: somewhere in MD
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check your valve cover gaskets. it'll just barely be leaking
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04-19-2018, 12:47 PM | #10 | |
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Quote:
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04-19-2018, 12:48 PM | #11 |
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I believe the plugs came out when I had the headers done. Nothing else was removed. CC pretty empty. Also I did get a flashing CEL, which means misfire, but it went off and AZ could not read any codes other then my O2 sensors which are tuned out.
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04-19-2018, 12:51 PM | #12 |
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If it's the VC gaskets, wouldn't I see oil somewhere? The engine is completely dry.
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04-19-2018, 01:40 PM | #13 |
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Maybe the plug seals are bad from not being torqued to spec from when the headers where installed? It might be worth while to put in new plugs making sure they’re torqued to spec and the seat threads are dry. Then check after a day or two to see what they look like. If oil is present then you know it’s not the plug seals.
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04-19-2018, 02:06 PM | #14 | |
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I have a misfire / spark plug issue
Quote:
Anyone know the torque specs for the spark plugs? Sent from my iPhone using Tapatalk Last edited by nyrfan; 04-19-2018 at 04:01 PM. |
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