One fouled spark plug?????????
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New User
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One fouled spark plug?????????
At least once a year my 92 F250 w/5.8L fouls a plug, the same one every time. What would cause this? ( I did replace the cap and rotor and wires about 2 months ago, The plugs were done about 6 months ago).
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Joined: Jun 2007
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Sounds like that one cylinder isn't firing for some reason. Is there anything touching the wire that may cause it disconnect from the plug? Is it a hard wire to put on and maybe you're not getting a secure connection? If cap & rotor are new and it's the same plug I can't see it being anything else.
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It's the one closest to the driver, I don't know the cyclinder order. I'm for the most part a sofa mechanic (watch a lot of tv shows and read on the internet about engines). I try to fix what I can, but like to know what's going on if I have to take the truck into the shop. When I say fouled plug I mean the plug is dry, is that right, or is a fouled plug wet??????????
Hotshot
Joined: Jul 2002
Posts: 14,285
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From: Bend,OR
that is plug 8 which is common to have problems for a few reasons. 1 is from a bad pcv valve and 2 from having the plug wires on 7 & 8 either touching or crossing each other which causes the spark to jump and hence fouls the plug. you might run some seafoam thru the intake and gas tank and replace the pcv valve. what brand/type spark plug are you running?
Posting Guru
Joined: May 2007
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From: North Reading Mass
I believe there was a TSB for relocating the PCV plumbing on the intake manifold. The mod basically reroutes the tube to a central position on the intake. You definitely want to do this mod or #8 will eventually fail.
regards
rikard
regards
rikard
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Hotshot
Joined: Jul 2002
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From: Bend,OR
first you need to pull those platinum plugs and install some motorcraft or autolite copper plugs. our fords do not like plat plugs not to mention platinum is not the best conductor of electricity. start the truck at night and look under the hood for your # 7 & 8 plug wires arcing. those wires must not touch at all, its a known issue.
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I'll change the plugs today and check for the arc tonight. When I pull the plug it's for the most part clean, it doesn't really look any type of combustion took place in the cyclinder. If it was not producing a spark shouldn't the plug be dirty and wet. Could the fuel injector be plugged?
Hotshot
Joined: Jul 2002
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From: Bend,OR
pull codes, www.fordfuelinjection.com has instructions using a paperclip. also check your fuel pressure at the rail with a gauge
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I'm taking the truck to the shop tomorrow, Blow head gasket and maybe a scratched cyclinder wall (#8 cyclinder). Thank you everyone for all the help.
Mike
I didn't check the compression. Going to let the Pros fix or replace the engine.
Mike
I didn't check the compression. Going to let the Pros fix or replace the engine.