1992 Ford Explorer spark plug wires

Tiny
MOSESLO
  • MEMBER
  • 1992 FORD EXPLORER
  • 4.0L
  • V6
  • AUTOMATIC
  • 200,000 MILES
What can happen if you didn't connect 4, 5, 6 spark plugs wires in and start vehicle as
Thursday, June 11th, 2015 AT 6:23 PM

7 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,873 POSTS
Your ignition coil pack has three coils that each fire two spark plugs, one on each side. If either spark plug is disconnected, neither of those two will fire, so the engine won't run. Spark is going to try to jump from the disconnected wire to the engine block. If it is successful, the mating spark plug might fire. That could allow the engine to try to run on one, two, or three cylinders. Carbon-tracking will develop in the spark plug boot(s) where the arcing occurred. That carbon-tracking conducts current and once those wires are reconnected, will allow the spark voltage to be shorted to ground rather than jump the gap on the spark plugs. You can end up with a misfire that won't clear up until the spark plug wires, and possibly the spark plugs are replaced. Those misfires may not show up right away. That could take a few miles to a few days.

If spark was not able to arc to the engine block, there may be no problem now. Just reconnect the wires and see how the engine runs.
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Thursday, June 11th, 2015 AT 6:51 PM
Tiny
MOSESLO
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Thank you I shut vehicle off right away disconnect battery just left alone tryed find what it can do I thank u very much and boots where away from plugs at time
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Thursday, June 11th, 2015 AT 7:25 PM
Tiny
MOSESLO
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Bty any chance is 142536 right firing order I got explorer 92 xlt4x4 4.0l ohv
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Thursday, June 11th, 2015 AT 7:28 PM
Tiny
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"boots where away from plugs at time"

That is the problem. The wires must be connected to the spark plugs to cause the current to go through the spark plugs and jump the gaps where it is intended to go. When the wires, with the boots on the end, are disconnected, is when the spark can't get to the spark plugs and it looks for an alternate path. That alternate path is the undesirable path where it arcs to the engine and leaves the carbon-track behind. Carbon conducts current poorly, but better than a spark plug, so from then on it may follow that carbon-tracking and bypass the spark plug. That's when the misfires occur.

Here's a diagram from Mitchell ProDemand online service manuals:
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Thursday, June 11th, 2015 AT 9:59 PM
Tiny
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What do you suggest
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Friday, June 12th, 2015 AT 1:50 AM
Tiny
MOSESLO
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  • 30 POSTS
Thank u so much for helping hooked it all back up it started right awsy
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Friday, June 12th, 2015 AT 9:58 AM
Tiny
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What do I suggest for what? You haven't indicated there's a problem.
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Saturday, June 13th, 2015 AT 6:19 PM

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