Reasons for false knock?
Reasons for false knock? I have tried everything to stop my car from knocking at wide open throttle and I have come to the conclusion that it is FALSE KNOCK. What problems have you guys encountered that causes false Knock?
TECH Apprentice
Joined: Jan 2002
Posts: 364
Likes: 0
From: Princeton, IN
How much timing are you seeing at WOT? The max timing I mean. Where does the knock start? RPM? And stops?
It could be false but you might also be seeing real knock but the computer pulls timing before it gets bad “to the point you would not beadle to hear it”
Does your car use a little oil? Have you looked in the intake lately? What about the back of the throttle body? If you have oil build up in the intake you will have carbon built up on the pistons and heads. I’m sure you have already tried and looked at all this but you must stop the oil from getting in the intake or your knock will not go away.
My car has always had knock, I just recently cleared it up. I have had 4 or 5 different pcv set ups and I finally found one that worked for me. it took the car 2k to clear out all the oil but my knock slowly started getting better then one WOT run I had full timing. 30deg, I was use to 25 or 26 if I was lucky with my knock.
I will be switching to the LS6 PCV system over the winter but what I have now is working and was cheap.
a pulley can cause knock, if it's unblanced or is not flush to the motor.
It could be false but you might also be seeing real knock but the computer pulls timing before it gets bad “to the point you would not beadle to hear it”
Does your car use a little oil? Have you looked in the intake lately? What about the back of the throttle body? If you have oil build up in the intake you will have carbon built up on the pistons and heads. I’m sure you have already tried and looked at all this but you must stop the oil from getting in the intake or your knock will not go away.
My car has always had knock, I just recently cleared it up. I have had 4 or 5 different pcv set ups and I finally found one that worked for me. it took the car 2k to clear out all the oil but my knock slowly started getting better then one WOT run I had full timing. 30deg, I was use to 25 or 26 if I was lucky with my knock.
I will be switching to the LS6 PCV system over the winter but what I have now is working and was cheap.
a pulley can cause knock, if it's unblanced or is not flush to the motor.
the wierd thing is it just started happening. it was fine when I got it dyno tuned and now about 3 months later I have knock above 3500 rpms. Mike at rapid took the car all the way down to 14* of tinming at woT and it still knocked. I ran GM top end cleaner through it and that did not help, I do have an ASP pulley but I don't see how that would just go out of balance all of the sudden. I never heard of the PCV causing knock but I will give it a try. Dissonance what PCV setup are you running? I guess I could also try and mess with the pulley too. keep the ideas coming I will let you know how everything works out.
I am not exactly sure how old the pulley is because I bought it in the parts section of this forum. It didn't cause any knock on the dyno that is why I don't think that is the problem. Maybe it is working itself loose I have to check it this weekend.
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Verdad Gallardo If the pulley isnt doing its job being a harmonic damper it can set off the KR sensor. Y-pipe and headers banging the chasis can also trigger a false KR.
I just spent weeks and mucho $$$$ tracking down a KR issue come to find out it was the SLP pulley causing all my issues. Went back to stock and all KR is gone
I just spent weeks and mucho $$$$ tracking down a KR issue come to find out it was the SLP pulley causing all my issues. Went back to stock and all KR is gone
Anything that makes the heads or block
ring can be picked up as false knock. The
knock transducers are just microphones
basically, there is circuitry that gates the
detect to certain windows around each
spark to minimize the pickup of other
mechanical noise but any engine rattle
that is crank- or cam-synchronous can be
picked up. Stuff like valvetrain clatter from
bad lifters or bent pushrods is a possible
source.
ring can be picked up as false knock. The
knock transducers are just microphones
basically, there is circuitry that gates the
detect to certain windows around each
spark to minimize the pickup of other
mechanical noise but any engine rattle
that is crank- or cam-synchronous can be
picked up. Stuff like valvetrain clatter from
bad lifters or bent pushrods is a possible
source.
TECH Apprentice
Joined: Jun 2002
Posts: 301
Likes: 0
From: Fayetteville, NC
If the pulley is the culprit for the false KR, would you get it only with a load, or anytime. Mine is only with a load, I can screw with my throttle in neutral and no KR, but I too can't remove KR on the street. I am about to order a new stock pulley and try that route, myself.
TECH Apprentice
Joined: Jun 2002
Posts: 301
Likes: 0
From: Fayetteville, NC
Mine happens at many RPMs. Esp if i gun the throttle, or if I hold a steady throttle I won't have any KR as the RPMs climb, then as soon as it shifts and the RPS drop I get KR and I never move the throttle. This is mostly between 2500-4500 RPMs. Also if I floor it I won't have any KR till i get high in the RPMs then it hits KR. This sucks!! 
try going back to the stocker adn see if that help. the bolt is only 3.00+. Have you tried using some high octane or copied the low octane gas tables to the high octane tables to rule out the possibility of real detonation
so should i not get pulleys? that was on my list but i dont wanna have and kind of KR from that. and i want to do headers too? do i have to worry there? otr just make sure i have enough clearance?
No I am not sayng not to get the pulleys. 2 yrs ago there were a lot of issues with different companies and their pulleys. It should all be straight now and it is safe to buy pulleys as all of the issues that I and others had to deal with are now corrected
TECH Enthusiast
Joined: Jan 2003
Posts: 582
Likes: 0
From: Birmingham, AL
OK guys, help me out. After LT and Y install, I get KR at 4800-5100 RPMs at WOT. Nothing is hitting on anything that I can tell... Right at 4800 I get 3.9 and it gradually goes down but not before it robs me of power. Any suggestions? I've switched to stock MAF, took off the MAFT and neither helped the problem. I can't hear any knock.
here is a better guess, maybe. did u do plugs and wires when u did headers? if so i would pull the plugs and make sure they all look like they are firing good. but here is what my problem was. check all the wires make sure they are all clicked in ALL the way, plug gets one clicks and the coil gets 2 clicks, on 2 of my coils i only clicked it one time and it made the car run shitty, so give thsi a shot