What to do about false knock?

[DarthMuffin]

I believe I have false knock on my SRT8. I'm seeing 6-6.5 degrees of ST knock retard, up to 3 degrees of LT ALWAYS, no matter what I do. Even with the stock tune, running good 92 octane gas with a bottle of octane boost in it, I get the knock retard. Running a diablo 91 tune with 10% extra fuel and -2 spark I get the same retard.

I've called the dealer and they won't touch it unless something is measurably wrong like a check engine light on. They say there is no published spec as to what is acceptable/normal knock retard (although I know everyone else gets zero, or maybe a few degrees only during a shift).

So, I'm going to try to tackle it myself. I figure the first thing I'll do is check the knock sensors. Maybe I'll just replace them, they can't cost that much, right? Anyone got a part number and can give me a torque spec?

Any other ideas? Will not torquing them quite so much make them less sensitive? Wrap the threads with teflon tape? I definitely want to stay on the "safe" side of things and make sure they're still doing their job though.

[MoPOWeR-349]

"...I definitely want to stay on the "safe" side of things..."

I'm no expert here and I'm sure the "Knowledge" will show up soon, but I would be very carefully with "just" adjusting timing and adding fuel. My stock SRT had about 3 ST knock retard and zero LT on the factory tune. With my new CMR tune I have about the same. I'm not sure if it will ever go away as the sensor may pickup phantom readings such as: valve-train chatter, aftermarket header/cats and shifting.

I'd recommend dyno time were the engine can be "properly" observed and adjusted appropriately. I also, believe you can adjust the sensitivity by reducing the voltage on the knock sensors or something like that. Someone will let you know how.

good luck...

[Dantra]

I seem to recall someones exhaust vibration causing something like this...was touching a xmember or frame somewhere.

Also remember Redfoxx having an issue with his knock sensors a while back. He may be able to offer some advice and parts numbers as well

[DarthMuffin]

Bump -- I hope Redfoxx does stop by. Just part numbers and a torque spec would make me happy and at least give me something to start with.

[Dantra]

According to my book, they torq at 15 ft lbs (or convert to inches)...make sure surface is clean

[uglyman8]

Have you thought about installing a catch can? That is what I am being told for my knock sensors also... But I am running cut outs and the different exhaust tone might be part of it. AND it only happens when the IAT gets above 80 degrees...Hope this helps...

[ForeignMuscle]

see what it does under conditions that should never induce knock, and that is your answer. get the tank realyl low and dump in some race gas.