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spark plug issue

 
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Old 20 Mar 2011, 05:31 pm
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Default spark plug issue

A few weeks back the number 2 spark plug blew out of the engine. My husband replaced the spark plugs, but it is still misfiring and missing. We had an auto store do a free "check engine light test" and it said there were problems with the num 3 spark plug and the knocker sensor. What and where is the "knocker sensor". Do you know about how much one costs?
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Old 20 Mar 2011, 05:47 pm
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Default Re: spark plug issue

Welcome to the forum.

I'm sure there's heck a lot more to your story because spark plugs just don't "blow out of the engine" unless it wasn't tightned down to spec in the first place (don't ask how I know- 67 VW bug ). Hopefully, you checked all the other plugs?

As far as the codes saying there were problems with #3 plug, like I said before, I hope you took out and checked ALL the plugs and tightened them down to specs.

The knock sensor if you have an earlier model PT is threaded into the front side of the cylinder block, near the starter. Remove the battery for better access.

The Knock Sensor: (from Answers.com on the Internet)

It allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.

A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.

The knock sensor responds to spark knock caused by Pre-detonation of the Air/Fuel mixture. As the flame front moves out from the spark plug ignition point, pressure waves in the chamber crash into the piston or cylinder walls resulting in a sound known as a knock or ping. This is caused by using a fuel with a low octane rating, overheating, or over advanced timing. Sometimes it can be caused by hot carbon deposits on the piston or cylinder head that raise compression.

As far as price. I've seen them anywhere from $17 to $50.
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Old 20 Mar 2011, 10:05 pm
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Default Re: spark plug issue

True!

You might have your husband check the plug wires, they lose resistance when
old, and plug / boots can get carbon tracked.

So he was able to just thread a plug back in?
Good for you!
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Old 20 Mar 2011, 10:19 pm
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Default Re: spark plug issue

Quote:
Originally Posted by CREWZIN View Post
Welcome to the forum.

I'm sure there's heck a lot more to your story because spark plugs just don't "blow out of the engine" unless it wasn't tightned down to spec in the first place (don't ask how I know- 67 VW bug ). Hopefully, you checked all the other plugs?

As far as the codes saying there were problems with #3 plug, like I said before, I hope you took out and checked ALL the plugs and tightened them down to specs.

The knock sensor if you have an earlier model PT is threaded into the front side of the cylinder block, near the starter. Remove the battery for better access.

The Knock Sensor: (from Answers.com on the Internet)

It allows the engine to run with the ignition timing as far advanced as possible. The computer will continue to advance the timing until the knock sensor detects pinging. At that point the computer retards the ignition timing just enough for the pinging to stop.

A knock sensor assures that you're getting as much power and fuel economy as is possible from your engine.

The knock sensor responds to spark knock caused by Pre-detonation of the Air/Fuel mixture. As the flame front moves out from the spark plug ignition point, pressure waves in the chamber crash into the piston or cylinder walls resulting in a sound known as a knock or ping. This is caused by using a fuel with a low octane rating, overheating, or over advanced timing. Sometimes it can be caused by hot carbon deposits on the piston or cylinder head that raise compression.

As far as price. I've seen them anywhere from $17 to $50.
That's funny,I had a spark plug blow out of my '67 Beetle.
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Old 22 Mar 2011, 09:23 am
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Default Re: spark plug issue

Spark plug wire resistance "increases" as the wires age (deteriorate).

Jerry
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Old 22 Mar 2011, 10:26 am
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Default Re: spark plug issue

So do spark plugs' resistances!

Modern (and older- See 3'ft+ wires on the '66 440) systems are easily able to
overcome this resistance, however, spark takes the path of least resistance ...

Don't get into the less resistance is better lie, wires must have 'suppression' to
avoid electrical interference. 'Flyback' has and will destroy electronic switches
in engine controllers. Stay with wires that meet factory specifications.
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Old 22 Mar 2011, 10:46 am
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Default Re: spark plug issue

I was simply commenting about your "spark plug wires lose resistance as they get old" in the post above! As wires age and deteriorate they don't "lose" resistance, their resistance increases. My comment had nothing to do with anything else you said in your last post. The rest any good mechanic knows. "Ignition 101" from the early 60's when my brother and I started our speed shop.

Jerry
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Last edited by wwpptc; 22 Mar 2012 at 06:50 pm.
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Old 22 Mar 2011, 10:49 am
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Default Re: spark plug issue

Interesting if you test the plugs, how high they get.

Do you remember the solid core wires?
How you could 'hear' them go by on your television?????
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