Wet spark plug

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papaabo
Posts: 2
Joined: Fri Apr 05, 2013 10:21 am

Wet spark plug

Unread post by papaabo » Fri Apr 05, 2013 12:13 pm

I have a 1999 3.1 lumina and is misfiring on cyl #4. I put new spark plugs and verified that spark plug is good I even switched plugs. New cables and cable is good verified continuity(switched also) coil checked and switched and is good. Compression all cyls @ 150lbs +/- 5lbs. Still cyl #4 is wet with gasoline. No check engine lite on. Fuel injector on cyl #4 reads 12.4 omhs. Is reading within specs?
There is no vacuum leaks.no water leaks.No jumping sparks (checked at night also.) Could it be related to fuel injectors or what?

Thanks

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ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: Wet spark plug

Unread post by ProTech » Sun Apr 07, 2013 7:36 pm

Well, everything you've checked seems to be ok. The compression might be just a tad lower than normal, but not by much so I wouldn't worry about that. Since all the ignition components seem to be functioning correctly, and if indeed you are getting good spark on the cylinder that is misfiring, it would pretty much have to be a fuel injector that is either stuck open, or just spraying too much fuel. The ohms reading is good, but that doesn't mean it can't be bad.

If you're absolutely sure that it's fuel on the spark plug, that is really the only reasonable answer, a bad fuel injector. If it's an oily mix that is fouling the spark plug, you might be burning excessive amounts of oil due to worn piston rings, valve guide leaks, etc.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

papaabo
Posts: 2
Joined: Fri Apr 05, 2013 10:21 am

Re: Wet spark plug

Unread post by papaabo » Tue Apr 23, 2013 4:09 pm

I cleaned all injectorrs and it is running smooth,BUT I am only getting 25mpg avg. I use to get about 28mpg. Would it help to changed valve guide seals like you recommended? Thank you very much.

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ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: Wet spark plug

Unread post by ProTech » Tue Apr 23, 2013 6:11 pm

You're complaining about a 3mpg difference? That's not really to big of a differential from what you were getting. Weather, gasoline quality, driving habits can all vary that number by a few mpg, so it's nothing to worry about. Changing valve stem seals, IF they are leaking, is not going to get you 3mpg more. Just drive it and be happy with the 25mpg you're getting.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

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