No check engine light but code stored?
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From: Paola
No check engine light but code stored?
I just got a sct x4 tuner for my expedition and figured I would check if there were any codes stored. I got a p0325 knock sensor code. The truck runs fine, and every time I drive it and then get home I check to see if the code comes back. I keep clearing it but it keeps coming back. I added some heet to the gas tank and recently changed an ignition coil on cyl 5 for a misfire.
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Joined: Sep 2006
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The sensor is located about even with cylinder 5 coil position down under the intake manifold on the side of the head.
Did you pull lead off or loose?
The sensor is a special crystal that responds to mechanical shock in the form of spark ping or knock.
It generates a voltage back to the computer.
This in turn retards the ignition timing as long as it detects ping or knock.
Excessive knock is dangerous to pistons, rings, bearings etc because it is an unwanted mechanical shock to those parts.
A missing knock sensor can be heard under high engine load as pinging or like marbles shaking in a can.
It comes about because the cylinder is fired 'to soon' in the crank rotation when the piston/rod relationship is to near a straight line when combustion occurs.
In a straight line relationship the piston/rod cannot move 'in response' to the cylinder pressure developed at time of combustion and is heard as a knock or ringing of the block parts.
The only way they moves is from the crank rotation already in progress by other cylinders.
Good luck.
Did you pull lead off or loose?
The sensor is a special crystal that responds to mechanical shock in the form of spark ping or knock.
It generates a voltage back to the computer.
This in turn retards the ignition timing as long as it detects ping or knock.
Excessive knock is dangerous to pistons, rings, bearings etc because it is an unwanted mechanical shock to those parts.
A missing knock sensor can be heard under high engine load as pinging or like marbles shaking in a can.
It comes about because the cylinder is fired 'to soon' in the crank rotation when the piston/rod relationship is to near a straight line when combustion occurs.
In a straight line relationship the piston/rod cannot move 'in response' to the cylinder pressure developed at time of combustion and is heard as a knock or ringing of the block parts.
The only way they moves is from the crank rotation already in progress by other cylinders.
Good luck.
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