Question about Knock

-H- · Oct 10, 2009, 04:39 PM

I am getting 1.8 counts of knock and I am concerned about it. I'm experiencing it at strange times though. It's not while I'm boosting. Under max boost the most knock I've gotten is .30. I'm pulling the highest knock under 1000 rpms and at very low speeds. Almost when I'm coming to a stop or when I'm coming from a stop.

What could be causing this? Should I be worried, or is normal? How can I fix this?

Thanks

mrubino83 · Oct 10, 2009, 05:01 PM

are you data logging? How are you measuring the knocK? evoscan?

-H- · Oct 10, 2009, 05:20 PM

data logging with Cobb AP.

rafa341 · Oct 20, 2009, 12:58 AM

ive seen the same thing have u figured out why

mrubino83 · Oct 20, 2009, 12:28 PM

bump. I would like to find out more about this too.

-H- · Oct 21, 2009, 10:45 AM

I've found from mutiple logs that when the most amount of knock happens it's at a very low rpm like sub 800 and little to no vehicle speed. I've driven it really hard and pushed up to 27.5 psi of boost. I've found that under hard driving there is virtually no knock. It only really happens at random right before idle or after idle.

I've stopped worrying about it since it's well below 3 counts of knock and if timing is getting pulled it's not while the engine is under any kind of strain. I only encounter any measurable knock when the car is not being pushed and there is no throttle.

UT_EvoX · Oct 21, 2009, 10:55 AM

This is completely normal. I've seen up to 12 counts of knock in EvoScan under low load/low RPM conditions. Nothing to worry about, probably isn't even legitimate knock anyway as I've tried to negate it with pulled timing and it still persists.

WickedWhite2008 · Oct 21, 2009, 01:15 PM

Quote:

Originally Posted by -H-

I am getting 1.8 counts of knock and I am concerned about it. I'm experiencing it at strange times though. It's not while I'm boosting. Under max boost the most knock I've gotten is .30. I'm pulling the highest knock under 1000 rpms and at very low speeds. Almost when I'm coming to a stop or when I'm coming from a stop.

What could be causing this? Should I be worried, or is normal? How can I fix this?

Thanks

My guess is your running too lean comming and going in and out of closed loop from open loop.

mrubino83 · Oct 21, 2009, 03:04 PM

bump. good theories.

tephra · Oct 21, 2009, 04:23 PM

yeh i've been seeing some very odd knock as well.

hunting for the cause/solution...

-H- · Oct 22, 2009, 12:55 PM

Mine is less than 3 counts maximum when it does happen. I'm starting to wonder if the weather has anything to do with it.

Does anyone know if the knock sensor could possibly pick up elements outside of the engine and it's components?

tipoytm · Oct 22, 2009, 01:18 PM

I'm experiencing this too (see the other thead Tephra recently started).

verkion · Oct 22, 2009, 02:29 PM

Quote:

Originally Posted by -H-

Mine is less than 3 counts maximum when it does happen. I'm starting to wonder if the weather has anything to do with it.

Does anyone know if the knock sensor could possibly pick up elements outside of the engine and it's components?

Yes...it will pick up on lots of things. I don't think the knock filters are written very well.

verkion

-H- · Oct 24, 2009, 07:56 AM

I've read that weather fluctuations like extreme heat or cold can cause the engine to act differently since the tune was most likely made for a baseline condition.

Plus the quality of gas, ie low octane can cause the engine to act differently.

I'm going to wait for a warm day and go fill up on 93 oct and put some octane booster in and see what the data log looks like.

rafa341 · Oct 25, 2009, 01:35 AM

good info