I just go the car back from the shop with a new head gasket. The car ran fine for 2 or 3 days then it starts knocking pretty loud and I get a code P0326 - "Knock Sensor 1 Circuit Range/Performance (Bank 1)". It knocks all the time ad speeds up when the RPMs go up. My first thought is fouled spark plugs which I will check tonight, I have replaced them recently but something could have happened from the gasket change.


Any one have any other ideas if it's not the plugs?


I did a lot of searching and couldn't find any info on constant knocking.

 

The right fuel? The right range of spark plugs?
`Carbon deposits?

 

My code reader reads freeze date. Thought I would share.


Trouble code: P0326
Engine Speed: 3329 RPMs
Calculated Engine Load: 92.2% (looks like I was accelerating)
Manifold Absolute Pressure: 24.5 "HG (not sure what that means)
Coolant: 199 Deg. F
Short term Fuel Trim Bank 1: -3.1%
Long term Fuel Trim Bank 1: -1.6%
Fuel System 1 loop Status: closed
Fuel System 2 LS: n/a


Not sure what that all tells.


Also, the place lost the intercooler cover. I didn't notice it until the knocking started, not sure this would cause that issue though (BTY, they are replacing the part)


FYI, I put in a full tank of 91 octane and added an octane booster.

 

From: http://www.obd-codes.com/p0326


Knock sensor connector is damaged
Knock sensor circuit is open or shorted to ground
Knock sensor circuit is shorted to voltage
Knock sensor has failed
Moisture in knock sensor connectors
Incorrect fuel octane
PCM has failed

My guess: The shop either damaged the sensor or forgot to plug the harness connector back on.

The sensor is located underneath the exhaust manifold between cyls 2 & 3.

 

the cover IS important...
it matches up with the hood part of the diverter....and forces air through the intercooler...
Guess the new headgasket could have failed from a bad install...maybe the old gasket was not scraped off....
In both cases...I'd being it back to the shop...and say fix it!! And get a diverter!!
I might get it towed in.....especially if the KNOCK is loud or bad.
Constant knocking is a possible sign of a failed motor...internally...so do not mess with it. get it back to the shop.

 

Turned out to be the spark plugs. I think the shop put in the wrong octane or it was left over gunk from the bad head gasket, or both. The old ones were fried, bad. I put the new ones in and as soon as I started the car the SES light was off and now the car sounds fine.


Hopefully that was it and there isn't some other underlying issue. Time will tell.

 

Beware: this "knocking" is not innocent, you can get a hole in cylinder.

 

Typically when a "knock" happens the spark plug takes the brunt of it...be it ping or knock...
Be VERY careful...a broken sparkplug might be more of a symptom than a cause...
I just wonder WHY you would think a shop would gas up your car??? I'm confused.....

 

When I dropped the car off there just happened to be 1/8 of a tank and when I got the car back there was 1/2 a tank.


The knock is gone with the new plugs. I'm thinking they got fouled from the bad head gasket (now fixed). If they foul and the knock comes back then that means there is something else going on.