False knock? Turbo L33

[amello7580]

Vehicle:
2003 Ram 1500 shortbed
L33 SBE
sloppy stage 1, yes 1
pac1218 springs, stock pushrods
Decapped Flex injectors
Stock ported fuel reg, 58psi base pressure
T4 Log manifold with crossover
VSR Billet 7875
VSR 44mm wastegate
Pump 93 from a "good" source
Poly engine and transmission mounts


IFR and VE scaled to get 210kpa (14.7psi) with 1.20 g/cyl for adjusting timing. Truck completely falls on it's face with the retard, I don't "hear" any knock and AFR's are very conservative, I have done a few different pulls at various afrs and timing changes but I still seem to get knock. I have messed with some of the knock settings so please take a look. I pulled 5% out of global and still get retard. It looks like false knock to me but I would like a second or third opinion. I haven't made det cans yet but will in the future. I should be around 11 degrees of timing with 14 psi of boost which is fairly conservative from what I have read.

Thank you in advance!

[ryan_axberg]

It looks like your running drive by wire, I would guess that it would be something with torque management. Maybe the spark retard vs torque reduction could be set to zero. Your knock sensors look like they shouldn't be very sensitive. Also you could set the knock recovery rate to something like .2 so then when it does retard timing it won't hold it so long and it will return a lot quicker to what you have the timing set to.

[amello7580]

Thanks Ryan, I'll try both and get back. The spark retard is still knock retard however as I am using the Knock Retard Channel. Judging by how it just comes in randomly under safe AFR and timing, I would say it is false knock since you only see 1 big spike followed by the decay. Can anybody who has has experience with false knock take a look and let me know if this looks familiar. Thanks again for community help.

[Davem3261]

I am having the exact same problem. My setup is very similar. 6.0 S475. What plugs are you running? Please post if you find out what was wrong. I will check out your tune later

[amello7580]

I am having the exact same problem. My setup is very similar. 6.0 S475. What plugs are you running? Please post if you find out what was wrong. I will check out your tune later

I am using the TR6 iridum, TR6IX I believe

[amello7580]

I am having the exact same problem. My setup is very similar. 6.0 S475. What plugs are you running? Please post if you find out what was wrong. I will check out your tune later

Knock sensor global was completely wrong, my original tune had a 1.0 value for anything in the 100kpa area, I "desensitized" them incorrectly. Going up in value desensitizes them, going down makes them more sensitive. Had to look through HPTuners online to get the right info.

"[ECM] 12955 - Knock Sensor Global Gain vs. RPM vs. MAP: Used to increase, decrease Knock Sensor sensitivity. Depending on model, a global load based gain for the Knock Sensor Level vs. Tip in TPS, Knock Sensor Level vs. Tip in RPM, Knock Sensor Level vs. RPM vs. Cyl tables. Multiplier value range is from 0 to 16."

^^ verbage sounds like the number in the boxes would be a gain multiplier which to a layman, i.e.: me, means that the higher the number, the more amplified the knock readings would be

Hope this helps, I used stock LS6 knock sensor data then correctly desensitized them by 5% (global) to help prevent spurious KR with the added noise from the engine and that worked fine, now im off to building a bluetooth det can solution so I can listen myself to be sure

[Davem3261]

Please post current tune. I would like to compare to mine.

[lukearmstrong1990]

what MAP sensor?

your VE numbers at tiny and your spark resolution is minimal?

[amello7580]

It's a 3bar OS. My engine ended up bending a rod at some point. Not sure the exact cause since there was no knock in boost until the piston started tapping the crank. I never pushed the truck too hard Stage 1 cam, 7875, 14psi, 11.2 afr and 12 deg timing, 93 oct. Gen 4 rods inside, all others were straight, never had the bottom end apart but I am leaning toward head gasket failure causing that cylinder to fill with some water and bend the rod slightly which was then exacerbated by some full throttle pulls on boost. Bore was 90% good so I slapped a new rod and piston in it and it runs great again. Take a look at this log though, it appears I have a knock sensor acting weird. Still need to dial in my idle with my new cam but It is looking pretty good otherwise.broken knock sensors perhaps.hplKnock.hpt

[steelmesh]

An effective method to determine false knock exists is to:

1) Pull a bunch of timing in the area of knock counts
2) Run high octane fuel (100+) temporarily. Probably get away with torco or boostane additives specifically

After you do 1 and 2 and there are no changes to the level of knock retard, then you can start desensitizing the knock sensor parameters and break out the detcans. If you are conservative with your changes to the knock sensor, the knock sensors will still function somewhat from what I have seen with the E67 and E78, but know that desensitizing the knock sensors increases the risk of engine failure (from reduced knock retard protection) especially if you don't know what the knock sounds on your particular engine. It might solve your power loss problem, so it could be worth the risk maybe.