• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

False KR vs Real KR

willie14

willie14

New member
So I'm in the process of tuning my car while I'm upgrading parts. I've just did my first log after my headers install which should of been done before. I'm reading 2* Kr between 13-15% throttle that does not stack on itself it just goes away. But when at WOT I'm at 6* kr which holds untill I let off throttle. Were wondering if my knock sensors are picking up my new headers vibrations so wondering if its all false. How is everyone distinguishing between real and false? Before I start upgrading more I feel I need to address this issue first
 




this tune will be in the trash when you top swap it. if your fuel trims are good then pulling timing will make the kr go away. no kr means its faster. kr takes your timing and kills it to save the engine.
 
be aware that the pcm may need up to 300 miles before trims will be learned. also be away that if the trims deviate far from 0 the pcm with test correct it back to the initial periodically for diagnostic purposes. this may result in kr that comes and goes even while under similar drive cycle.

if you are worried about vibrationional cause, you can look for powdered rust near close areas of the pipes if they are touching. check all mount condions and make sure its level across the core support and VC grooves (just look by eye with your head level with vc/core support)

if engine movment is the cause with the exhaust flexing the headers upward you can get it to do it sooner by temporarily remnoving the resonator mounts

but yeah na engines have the KR sensors at a tighter tq so they are more sensitive aside from the pcm file differences
 
Yes still NA for now. I'm aware were gonna have to retune after then swap, but id like to see what power I can make with what I have on there now
 
If I tuned down sensitivity of my KR sensors to not pick up so much if they're reading the header vibration will I have to worry about it not being able to pick up real KR?
 
you sound like you've been talking to zach howard. don't mess with the knock sensor sensitivity. an N/A timing table is so different than a supercharged table.
 


I never had to do that when I ran headers. I never thought they were too sensitive to begin with. And to comment on what 400SBC said, I thought I've read that both engine require a 14 ft lbs torque spec on the knock sensor, that's what is was if I remember right for my 2000 GTP.

If anything is rubbing on the headers or the o2 sensor it touching the firewall, that can cause false knock.
 
Not really, it doesn't harm anything.

If you were to look at any of the latest GEN 4 V8 computers or any of the recent GM V6 computers, the amount of predicted knock that is built into the computers is crazy. They run really high timing tables from the factory but they are retarding the timing on a regular basis and it's just normal. You'd never even know they are "knocking" because it's all a predicted number that the computer makes up just to keep things running how they want it. They also want you to be able to run 87 octane in everything now, another reason they do this stuff.
 
Fivefingerdeathpunch said:
I never had to do that when I ran headers. I never thought they were too sensitive to begin with. And to comment on what 400SBC said, I thought I've read that both engine require a 14 ft lbs torque spec on the knock sensor, that's what is was if I remember right for my 2000 GTP.

If anything is rubbing on the headers or the o2 sensor it touching the firewall, that can cause false knock.
Click to expand...

I know the later series 1 and the early series 2 had different part numbers for the naturally aspirated vs. Supercharged knock sensors.
for the series 2 from what I remember they share the same part number but the supercharged engines are only Titan to 19 foot pounds while they naturally aspirated engines are tightened to 26.
It's been a while but I swear that I've seen that in a GM Service annual
 
Ok False or real NA vs Boosted yea sure it does matter. I'm staying NA for at least a few months now so I can finish the body sea for now and this Is also my DD and a car in eventually gonna put on the track, but anyways I'm being NA for now I'm still losing 6* of timing @ WOT. Neather the less wed were going to fill up with premium and hook up the wideband and relog again. As for my current o2 sensor, I had another thread about bad car vibrations while being in reverse. I solved that issue by knocking more firewall clearance out but maybe its still not enough. I was told zzp's o2 sensor is smaller but if im going to hook the wideband up then I would just have to work out the clearance for that.
 


Well premium fill up and second log performed with still the same results, same 6* KR. tuned Down the knock sensors to same level as stock gtp setpoints and KR reading zero all the way thru throttle band. **** was just picking up too much headers vibrations so were gonna run thru the whole entire frame and see if we can ease up the vibrations a bit.
 
You must log in or register to reply here.
Back
Top