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carbon (fuel) fouling spark plugs

allenhudson91

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Joined
July 11, 2009
Messages
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City, State
Birmingham, Al
Year, Model & Trim Level
1993 4.0 XLT
I have a 1993 Ford Explorer XLT 4.0. My spark plugs are carbon (fuel) fouling on the passenger side of the engine. I have no idea what could be causing it. Any ideas? message me if you need any more details. I believe it has something to do with either the fuel or the spark on the passenger side of the engine.
 



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YBCold

Explorer Addict
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January 4, 2009
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City, State
Las Vegas NV
Year, Model & Trim Level
91 ×∟┬
maybe the injectors are stuck open?
 






glfredrick

Explorer Addict
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January 25, 2003
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City, State
Louisville, Kentucky
Year, Model & Trim Level
86-98 Ranger STX
Which plugs are you running? It takes a double platinum plug -- and preferably a Motocraft to deal with the lost spark system in these trucks.

I'd check for leaky injectors next.

Have you run a compression test? While we have the advantage of being able to plug scanners into the newer vehicles, there is no substitute for the tried and true tests.
 






shaggymane

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March 4, 2008
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City, State
topeka, kansas
Year, Model & Trim Level
91 navajo
Which plugs are you running? It takes a double platinum plug -- and preferably a Motocraft to deal with the lost spark system in these trucks.

I'd check for leaky injectors next.

Have you run a compression test? While we have the advantage of being able to plug scanners into the newer vehicles, there is no substitute for the tried and true tests.

Would you explain about that lost spark system or link a thread?
he's in a 91. I thought that complex spark stuff started later, like Gen II?

Those double plats in mine fouled so I went to champs.
 






glfredrick

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City, State
Louisville, Kentucky
Year, Model & Trim Level
86-98 Ranger STX
Get rid of the Champion spark plugs... That is about 90% of your problem. Find some Autolite or Motocraft double platinum plugs of the proper heat range for your engine and run them.

The lost spark (called waste spark by Ford) is used on all the Explorers. Essentially (in simple form) it is one set of coils that fire one bank of cylinders on the positive side and the other on the negative side -- thus the need for double platinum plugs (factory uses different plus on each bank of cylinders, but that is expensive and a lot of work to procure).

Here's a site that explains it in more detail:

http://rockledge.home.comcast.net/~rockledge/RangerPictureGallery/DIS_EDIS.htm

After reading the article, you'll understand why the proper spark plugs (the ones designed by Ford to operate with the ECM) are critical.
 






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