Serioussn95

iTrader: (1)

hey guys, I am killing myself trying to figure why and the hell I have so much knock in this truck. ANY HELP is greatly appreciated. mods are listed below. I have pulled damn near all of the timing out of this thing and it is still knocking its *** off. The scan is just a normal part throttle scan a few miles down the road. Motor is fully built using 93 pump octane. It does still have stock injectors and (newer) fuel pump. VE/Maf is tuned within 3% but injector duty cycle is topped out at WOT so we are in the process of doing pump/injectors. The knock sensors are new but its possible they could be bad, I've even seen it throw knock at idle with no load on it???? Would switching to a Non projected tip plug help as well? Anyways, any help with the tune/scan is greatly appreciated.

02 Silverado crew cab
Iron block forged 370 (wiseco flat top/scat h beams)
Tick stage 2 turbo camshaft 231/231 .630"/.605" LSA115+5
243 heads 10:6:1 compression NGK TR6 plugs
ls9 gaskets
arp headstuds
BTR .660 spring kit
trunnion upgrade
Stock injectors and truck intake
stock manifolds, no cats, flowmaster 44 out the back

Fresh 4l80e HD2 shift kit
Circle D 2800 billet
33s 3.73 gears

warriorpluto

iTrader: (2)

Let me know what you find out. I have the same problem except with a stock engine and stock tune

Luke19901

would suspect that codes P0325/P0327/P0332 are logged causing excessive retard

your knock sensor gains are quite sensitive.

also reduce your PE TPS to 20% across the board and set enable MAP to 65..... being a heavy truck it doesn't appreciate 80kpa+MAP at 1800ish rpm and no enrichment. that's causing knock

Serioussn95

iTrader: (1)

Thanks Luke. Had a friend look into the tune to make some corrections and all is good now. Turns out the knock sensitivity was way high and due to the valvetrain/piston combo it was recording false knock like crazy. pretty much put the timing back to stock , reduced sensitivity and played with the knock retard (out of PE) and it runs great. I think I was being overly cautious since I built this motor as well as being the tuner. This is one of the big motor builds ive done so being used to working with stock/bolt on motors seeing all the knock scared me.

scoob8000

Just a quick FWIW that I learned a few weeks ago. Not your issue, worth having in the back of your mind. Any current or pending (second error reported), even without the CEL lit can cause the PCM to pull the max timing that you are allowing in knock retard. Turns out I had P0332 set to second error even though I don't have a b2 KS, so the code was always there and soon as I'd enter PE I'd see max retard. Gen3 PCM.

Serioussn95

iTrader: (1)

great info scoob, thanks for sharing that