Knock sensor, see dealer.

[TRDon]

For the second time in as many times out, this message came up. I never had it except when the wire came off the sensor 2 years ago. I am still burning a little bit (less than 1/8 of old gas to 3/4 new gas) of last years gas and I did call PCM and I was told that excessive knock retard (he thought 7* or greater) or 0 retard will activate this code. I planned on erasing the code and getting some fresh gas and trying that, but also might have to get a new sensor if it comes to that. I might have my dealer put his diacom on it and see where it goes with the KR too.

I was just curious if anyone has had an issue like this and what happened with it. I have a gameplan unless someone else has a better idea in this situation, but always looking for more input.

[NautiqueJeff]

It is possible that when the boat was last winterized, the block plug with the knock sensor was overtorqued. The torque rating on that plug is very low if I remember correctly. Might be worth a check.

[svwc]

do NOT apply any type of pipe thread lube or tape
the knock sensor threads must short (ground) to the block

[WakeSlayer]

do NOT apply any type of pipe thread lube or tape
the knock sensor threads must short (ground) to the block

Same applies to temp sending units. Do check this.

[Sooner]

Knock Sensor

I had the same message show up this weekend. Which block plug has the knock sensor. Is it the round black one with the insert at the front of the engine?

[WakeSlayer]

On my 502, it is the forward one on the port side. There is a wire coming out the end, and it doesn't look like a block drain.

[CradGen2]

I normally only hand tighten the sensors. Maybe I put a little wrench on them but apply very little pressure. Haven't had an issue.

Maybe just replace the sensor. I can't imagine they are expensive, but I don't know that. Also it could have been dropped. I do know they are sensitive.

[AirTool]

They are fairly cheap...maybe 30 bucks or less.

For lake water cooling, hand tight is what I would do. The pressure in the block is low.

For closed loop cooling, I'd torque per spec if possible to reduce leaks/pressure loss. Closed loop systems are pressurized like your auto. Overtightening will damage it.

[TRDon]

PCM said the sensor was about $60. I cant imagine any of the sinerios you guys mentioned apply to me bacause I winterize the boat myself and the knock sensor was not touched since november of 2009. Last year I did it differently and put my boat in heated storage. I didnt drain the block, I just ran 6 gallons of pink stuff through it until I got it out the exhaust and then some. It might come to replacement, I am all for it especially if it works. I havent gotten that far yet.

[AirTool]

PCM said the sensor was about $60. I cant imagine any of the sinerios you guys mentioned apply to me bacause I winterize the boat myself and the knock sensor was not touched since november of 2009. Last year I did it differently and put my boat in heated storage. I didnt drain the block, I just ran 6 gallons of pink stuff through it until I got it out the exhaust and then some. It might come to replacement, I am all for it especially if it works. I havent gotten that far yet.

Was the boat subjected to freezing condition? it is unlikely but possible water stayed in the knock sensor and then froze. Since no water flows through it, it may have stagnant water in it.

Unlikely - but possible in a deep freeze. There is nothing around it but cold air.