C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Spark Plug Fouled Out...Need Help

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Old Oct 20, 2007 | 05:25 PM
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Default Spark Plug Fouled Out...Need Help

Hi, I have a spark plug that keeps fouling out. I think Ive seen somewhere that you can buy an extender to keep ot from fouling out???? Is this true, and are there any other tricks to try and keep it from fouling out. Thanks guys, Zak.
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Old Oct 20, 2007 | 05:50 PM
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Yes, but that is a hack, temporary, repair. It is best to change plugs until you can get to fixing it. If it is fuel fouled, you need to fix it ASAP, as you are also diluting your oil. That puts you on the edge of a disaster. Otherwise it is oil and unless you have a low mileage engine that shouldn't need repair, it is really a time for an overhaul. You can check and diagnose where the oil is coming from, but unless it is valve stem oil seals, which really shouldn't foul plugs very quickly, it is time to yank it.

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Old Oct 20, 2007 | 08:32 PM
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Originally Posted by CFI-EFI
Yes, but that is a hack, temporary, repair. It is best to change plugs until you can get to fixing it. If it is fuel fouled, you need to fix it ASAP, as you are also diluting your oil. That puts you on the edge of a disaster. Otherwise it is oil and unless you have a low mileage engine that shouldn't need repair, it is really a time for an overhaul. You can check and diagnose where the oil is coming from, but unless it is valve stem oil seals, which really shouldn't foul plugs very quickly, it is time to yank it.

RACE ON!!!

Our mechanic said it was the valve seals, but he BS the price. He said we needed a valve job and he wanted to charge us $1500. I can go get a crate 350 for that much. What do you suggest I do? Its only the #5 cylinder my mechanic told me. Thanks, Zak.
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Old Oct 20, 2007 | 08:43 PM
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You have a couple of choices. Number one, do a cylinder leak down test to determine if there are any compression leakage problems and where. If you find none, you can gamble the $20.00 for seals, $10.00 to $20.00 for valve cover gaskets, and a weekend to change the seals yourself.

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Old Oct 20, 2007 | 08:50 PM
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CFI in his other thread I suggested he check plug wire then compression first. He never mentioned what kind of fouling or if it was smoking. Just a couple of cheap easy checks.
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Old Oct 20, 2007 | 09:16 PM
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Originally Posted by arandy
CFI in his other thread I suggested he check plug wire then compression first. He never mentioned what kind of fouling or if it was smoking. Just a couple of cheap easy checks.

Well its not smoking, and my mechanic said it was the valve seals. How difficult a fix is this? Im 16, can me and my Dad fix it relatively easy? Thanks, Zak.
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Old Oct 20, 2007 | 09:36 PM
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If it was valve seals the car would smoke upon startup after sitting for awhile. After it's running it'll stop smoking. When the seals get really bad, the back plug on either side will oil foul. I had a 78 Z-28 back when I was just outta high school and I carried a box of plugs and a plug wrench in the glove box because one would finally get so fouled it wouldn't fire at all. Did make the car sound like it had a nice cam in it right before it fouled out completely.
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Old Oct 20, 2007 | 09:49 PM
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So what do you guys think I should do?
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Old Oct 20, 2007 | 09:55 PM
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check your plug wire first
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Old Oct 20, 2007 | 10:10 PM
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Originally Posted by Pryderei
check your plug wire first


Ill do that tomorrow...Thanks guys, ill let you know how its going tomorrow.
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Old Oct 21, 2007 | 11:42 AM
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Is the plug wet from fuel, or oily? Fuel could be bad plug wire, distributor cap, stuck injector.
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