oil fouled spark plug

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berry
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Joined: Sun Sep 02, 2012 11:29 am

oil fouled spark plug

Post by berry »

hello I need your help

four days ago I changed all spark plugs. one of these was oil fouled in cylinder no 5 on the driverside the nearest to the driver. chilton says that this indicates worn piston rings and/or bad valve seals.

what are your experiences with oily spark plugs?

is there maybe a relation to the bad idling?
watch here:
http://www.beretta.net/forum/viewtopic. ... 38#p108338

and to the oil in the intake?
http://www.beretta.net/forum/viewtopic.php?f=5&t=14161

thanks!
...cruising
92 GT 3.1 MPFI auto 57K white

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Koots
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Location: Goose Bay, Labrador

Re: oil fouled spark plug

Post by Koots »

Did you get around to changing your PCV valve or try cleaning it out?

I would just go ahead and replace the valve, but if it's easy to change out, then cleaning it is worth a shot to see if it will fix your problems. I've got a ton of Chevy/GMC trucks with V8 motors and all their PCV valves can be pulled in seconds. I still end up replacing them all anyway, because we get the benefit of super cheap, readily available parts for these vehicles.

If it's fouling just one plug, that cylinder might hold the key to why you are getting excessive oil/vapours in the intake. If you have a bad valve seal or bad piston rings, this would probably be the cylinder with the issue.

Once again though, a blocked up PCV valve can cause excessive pressure buildup in the crankcase, which will cause oil to pressurize it's way out of any weakpoint it can find. Most of the time it's the rear main seal or valve cover gasket, but it will find it's way through any place it can when the pressure builds like that.

Anyway, I better stop typing :beer:
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berry
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Re: oil fouled spark plug

Post by berry »

I see the reason of the oily spark plug and bad piston rings and/or bad valve seals is maybe a bad pcv-valve.

***
EDIT I didnt change the pcv yet but Im working on it. First I have to find out which parts I need to buy. Intake gasket and PCV...
***
...cruising
92 GT 3.1 MPFI auto 57K white

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Money pit Beretta
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Re: oil fouled spark plug

Post by Money pit Beretta »

You only need the upper gasket if the rubber hose that goes from the upper to the PCV breaks.
keep'em flying!
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berry
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Re: oil fouled spark plug

Post by berry »

I had to read it twice. first I thought I have to buy
a gasket for the upper intake anyway.

today I cleaned the pcv. watch the thread:
http://www.beretta.net/forum/viewtopic.php?f=8&t=13899
...cruising
92 GT 3.1 MPFI auto 57K white

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Rettax3
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Re: oil fouled spark plug

Post by Rettax3 »

Regarding the PCVs in our V-6s... They tend to be installed in the rear bank (I am specifically thinking of the MPFI engines) valve-cover... But then there is a breather-tube placed in the front valve-cover that runs directly into the intake before the throttle-body... Does anyone else get the feeling that the PCV is placed on the car just to give you something else to buy for it? Seriously, if pressure is building up in the rear valve-cover area, wouldn't it just 'flow' through the crank-case to the front bank's valve-cover and get expelled through the breather tube?
Sorry Berry, I'm honestly not trying to jack your thread, I've just been pondering this one for a while here, and thought maybe someone has a good answer for this...
1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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