knock issue

**copperpacecar** · 04-17-2011

my mods are...high compression block, xp cam, springs, speed daddy headers, gen 5, meth injection, northstar, 3.29 gears, and 3.1 pulley...problem is im getting bursts of knock at shift...itll hit 9 and drift down to zero but half the time it wont do it at all. took the timing down to 13 and ran the larger meth nozzle with very little difference. what could be causing this?

**redlinepontiac** · 04-17-2011

false knock maybe?

**copperpacecar** · 04-17-2011

ive heard of the term knock burst...i believe its that...and a 9 for false knock...thats a bit high but also ive never run 3.29 gears and this horsepower before

**redlinepontiac** · 04-17-2011

hm never heard of knock burst, lol time to google

**01gpgt01** · 04-17-2011

Knock burst is usually when your just entering boost. You get a degree or two. Being at your shift Id assume its maybe a lean spike. Or maybe false. take the blower belt off see if it does it. Add some octane boost. does it go down or disapear?

**copperpacecar** · 04-17-2011

well it spikes a nine at best and takes a few seconds, maybe three at most, to drift down to 0 where it stays. can false knock actually register that high and take that long to fall back? i first assumed false with as hard as the tranny shifts but the number seemed really too high for false and took to long to disipate unless im wrong as im very new to this setup

**copperpacecar** · 04-18-2011

took her out again and it also does it everytime i enter boost but for some reason it only flares to 4 now and settles almost immediatly and i did about ten hard pulls with it...also seems to have a coil pack goin as it studders just a little at wot

**Fivefingerdeathpunch** · 04-18-2011

Why and the fudge is your timing so low?
I think its more than a false knock or whatever issue.

**01gpgt01** · 04-18-2011

Whats your AFR? Studder at WOT sounds like a lean issue. One thing id suggest is droping PE to 27 28 percent. that way its fueling right before you hit boost

**copperpacecar** · 04-18-2011

thanks for the responses guys....first afr is 10.5 at wot. Second the cranked the timing that low because of the knock...my first run without the meth my timing was 18 and it flared a 13 on the knock scale...i ran it down to 13 and added the meth and now its down to what i stated earlier...i figured the studder was a coil pack acting up and was gonna buy a new one and rotate them around to see if i can find the bad one as my resistnces are all withing range if not ill try the wires

**Bio248** · 04-19-2011

why dont you tune it without the meth first, then add the meth in and add timing/boost? it doesnt make sense that youre throwing all these variables at it and making it difficult on yourself.

also, with a 10.5 AFR youre running too much meth. way too much. think of it as a secondary fuel. you dont want a crappy AFR, ever.

**copperpacecar** · 04-19-2011

i was gonna tune without the meth bio but with the knock where it was and still is im hoping it buys me some time to figure out whats wrong before i blow the motor again...also found a very small leak on the front header...could this cause that much knock?