need some help with spark knock

[Supraboy89]

this one has me puzzled i am not sure if it is the 102degree heat or what. ok car runs great but when the motor warms up and when i start to hit about 2 to 3 pounds of boost i get spark knock. when i go wot it goes away. now i run 93 octane all of the time i have the timing set to 10degrees there is no check engine light on checked for codes no codes. all of my sensors work good engine starts up fine and runs great. when i drive for about 20min and the motor is good and hot i get the spark knock. no signs of overheating i have a bran new raidator new stat all hoses are new. i run the car with the afm screw backed out for more boost but i set it back to stock and it still has spark knock? please help me if you might have an idea thanks.

 

[WhtMa71]

What plugs do you have? Might have to go a step colder or maybe to some iridium plugs.

 

[IwantMKIII]

i'm getting the same thing on my new motor, except it happens only at an idle. anywhere from 0-25Hz. I put in the octane booster and new feul and that seemed to help the problem somewhat. I don't know why im getting it either, i have NGK R plugs too.

 

[Nick M]

The basic information you supplied isn't normal. Either it isn't knocking, or if it is there is, you should have a 53. If you don't have codes, the only thing would be to have a knock sensor that makes a signal, but a weak signal. But I haven't seen that too often. If you have a 52, the engine changes operating parameters, and that makes it very difficult to detonate.

When and how are you hearing your knocking noise? Under load, detonation and a collision of flame fronts is worse.

It would be benificial to check the output with your meter on Hz scale, or better yet a DSO.

 

[3p141592654]

Find a long hill and drive up it while its pinging lightly. The ECU should adjust the timing and you will hear the pinging subside after about 10 seconds. After that it usually will be gone completely for a a few days, then start to come back. Around here, there is a freeway with a long uphill section (118 Santa Susana pass) that was perfect for this test.

I had something like this for years. The solution for me was to rebuild the engine and decarbonize the pistons and combustion chamber. That cured the problem completely.

 

[IwantMKIII]

Find a long hill and drive up it while its pinging lightly. The ECU should adjust the timing and you will hear the pinging subside after about 10 seconds. After that it usually will be gone completely for a a few days, then start to come back. Around here, there is a freeway with a long uphill section (118 Santa Susana pass) that was perfect for this test.

I had something like this for years. The solution for me was to rebuild the engine and decarbonize the pistons and combustion chamber. That cured the problem completely.

As my computer 'learns' of the knock (i assume mine is like his), it actually makes it progressively worse and works its way up the RPM range......weird. I found simply resetting the ECU fixes it best. Lasts about 1/2hour or until you turn off your car.

 

[IwantMKIII]

delete

 

[Supraboy89]

thanks guys for your input . this problem has been a mine teaser to try and solve. to answer what redEj8 asked yes i am running iridiums.