Just a few questions i need some help with.

[87LimitedT]

What exactly causes knock not enough fuel to much my scan master usually starts showing when it starts to rev high or when it gets close to shifting sometimes from 2 all the way up to 7 point something it will stay for a little and go it sometimes sputters when flooring it to the O2volts usually at idle will jump from mid 500s to high 700s when flooring it jumps from high 600s to high 700s on the O2 I no im running a little rich I sometimes get a huge puff of black smoke when I floor it a guy at work said it could be false knock that something could be loose and could be hitting or tapping n something that is causing it to show I could use some help.

 

[jerrad]

Knock is mostly caused by not enough octane for the boost/timing that your car is running at.

 

[87LimitedT]

well i usually use the 94 at Sunoco and i have a turbo tweak street chip if that helps any could i just be running to much boost.

 

[my1stgn]

the computer sees knock as any vibration in the bottom end. It is usually caused by the fuel/air misture igniting before it is supposed to ignited (via the spark on the spark plug) If it ignites before it is supposed to, it will push down on the piston (which is still coming up) and this will cause a vibration that the knock sensor sees. So the car will retard timing to ignite the air/fuel before it self ignites. So if the air/fuel mixture ignites because it is too hot in the cylinder, this excessive heat can be caused by too much boost (compressing air causes heat) or too little fuel (fuel also cools the air before it ignites, a lean mixture will burn hotter than a rich mixture)

Also higher octane fuel burns slower than lower octane fuel. So if you increase octane, the chance of it pre-igniting lessens because it burns slower and will not be likely to igniting, pushing the piston down before hand. Therefore, slower burning fuel (higher octane) will make more power by adding timing or adding boost.

 

[IATurboBuick]

thats an awesome response. thanks

 

[GNRick]

What exactly causes knock not enough fuel to much my scan master usually starts showing when it starts to rev high or when it gets close to shifting sometimes from 2 all the way up to 7 point something it will stay for a little and go it sometimes sputters when flooring it to the O2volts usually at idle will jump from mid 500s to high 700s when flooring it jumps from high 600s to high 700s on the O2 I no im running a little rich I sometimes get a huge puff of black smoke when I floor it a guy at work said it could be false knock that something could be loose and could be hitting or tapping n something that is causing it to show I could use some help.

That has to be one of the longest sentences I've ever read! Not to be sarcastic, but if you want help here, you should make it easy on the people who can help you and not force them to have to correct your grammar AND think of a response. Anyway, I hope you get your problem fixed.