haggi961

Hey guys,
I have some crazy false knock problems well I think it’s all false knock but can’t work out why.
Anyone else have something similar problems when you came across mapping the car? The spec of the engine is:
Harrop Supercharger HTV 1320
Le9 2.4 oem crank
75mm ls4 throttle body
Stage 3 comp cams
L61 head
GM Racing Valves 0,5mm Oversized
Supertech Dual Valve Springs
Max Ported Head
Le9/ 2.4 88mm Gen 3 block
Forged & Coated Je Pistons for Compression
9.0:1
Ecotec 4340 Connecting Rods
Full 3 inch exhaust system
Crank balancing/polish, pistions/ Rods balancing, block honed, block and head skimmed
Helix 6 paddle clutch
TTV lightened flywheel
Balancer delete
ARP head bolts
Cometic head gaskets
Ati ATI GM Ecotec Super Damper

With the software I’m using I can ignore the knock or totally switch the sensor off but would like to discover why it’s doing it before doing that. From what I’ve found on the internet of the le9 block, it has one knock sensor bolted next to the oil filter housing with the tail pointing at 9 o’clock position. The knock sensor I’m using part number 12621820, just to make sure there isn’t a different knock sensor used for the le9 block. I did find this picture which made me think is there maybe two knock sensors on the le9 block?


Here is a graph of the knock I’m having which is purple in colour. You can see it’s a straight line of knock from 6 degrees to around 5 degrees at the end. This for me is weird as there is no spikes and it’s completey straight.


My friend who has similar engine specs to me has the same problem with around 5 degrees of straight line knock, so I know it’s not a faulty sensor.

Slowbalt2000

iTrader: (1)

For some reason, le5 builds seem to be plagued with this issue, including my own. What software/ecm are you using? And is that efi live?

The picture of the engine you posted is an LNF, they use two sensors, le5 only uses one.

haggi961

This is what I was thinking I would find is that it’s a common problem as I’ve never seen this before.

The software is Obd tuner, which is basically the oem Ecu that’s been built into a stand-alone software with all the oem protection is used. It’s really clever stuff but not sure if you guys have heard of it.

Have you or anyone else got past this problem as there is a few high powered supercharged le9 builds out there? To add I’m also using 100% water injection now but this made no difference to the knock.

slapbetcommissioner

iTrader: (3)

Can you turn down the knock sensitivity? I've heard of this issue with lsj as well with more aggressive cams specifically.

Slowbalt2000

iTrader: (1)

The software we have here in the states for the le5 allows adjustment of knock sensitivity. His looks like its not as unlocked as hptuners is.

haggi961

Thanks guys for the help. With the Ecu and software all that can be done with the software tuning is
Switching the knock off or forgetting a certain amount of knock. So if I definitely know it’s 5-6 degrees of false knock I can forget it and then the next run will start again with fresh results.

I need to know it’s definitely false before I do the second option.

slapbetcommissioner

iTrader: (3)

What are you running for fuel?

jdbaugh1

iTrader: (1)

Not saying this is good advice as my situation is far from ideal and I wish I could use my knock sensor but with 05-06 there is no knock sensor sensitivity adjustment that my tuner can modify. This leads me between the choice of using my knock sensor and pulling loads of timing all the time or not using the knock sensor and sending it. I can tell you that without the knock sensor pulling timing I can actually hear audible knock when it happens. People say you can't always hear it but I recently had an episode where my meth pump went out and while trying to diagnose I did a few pulls each time hearing slight knock and letting off. Not completely suggesting you disable your knock sensor and listen for real knock but just letting you know I do think it is possible to do.

haggi961

Just super unleaded which I think is 95 octane or 98 from my local garage.

haggi961

I’ve seen ways to make det cans on the Internet which might be a option. First thing will be a safe ignition timing (something like 10 degrees at full boost) and then disable the knock retard system. Then advance the ignition timing in small steps to see where it brings me. After this enable the knock retard system again and see if it still retards the ignition and maybe then tune it down a little bit so there is still protection.

Would be nice to know why it’s causing this before doing any of this mapping but think it’s one of them problems that won’t be easy to find.

Slowbalt2000

iTrader: (1)

links to instructions for det can?

haggi961

https://www.hpacademy.com/forum/gene...ning-for-knock
I was looking at making this version.

steelmesh

As for the reason, a tuner that helped me get some power pulls on the dyno asked why my timing was so conservative (because I was going off stock KR) and he said it was probably the forged crank and rods in my 2006 LE5 that is making the false knock and I should be running more timing with the meth I had.

I desensitized the knock sensor (with hpt) and reduced the aggressiveness of knock strategy, I was able to add a few degress timing without issues with actual knock...from what I could hear. I tried to make a $12 electronic det can, but it was too noisy with static. I would like to try out the analog tube style det can that was linked. My seat of the pant dyno said I added torque because I never spun the 275's consistently after shifting to second gear until I bumped up the timing.

I also desensitized my LUV 1.4T ecotec, without a doubt I was getting real knock after this, so I reduced timing and it went away. It is much easier to hear knock without any type of amplifier with this little powertrain.

haggi961

How do you guys turn the knock sensor down with your software? Do you adjust the pick up frequency and if so did this work?

Slowbalt2000

iTrader: (1)

There is a table titled "knock sensor sensitivity" for each cylinder. I believe the axis are cylinder airmass and rpm.

steelmesh

At your own risk of blowing up your engine: you adjust the decay rate (so it recovers from retard quicker), minimize attack retard, disable/reduce burst knock



Again at your own risk of blowing up the engine: you can adjust the multipliers for each cylinder here

haggi961

Thanks for the information and definitely have more input in the knock sensor then the software I’m using.

Slowbalt2000

iTrader: (1)

I dont see any pictures there? Looking for advice on what materials to use and such.

Slowbalt2000

iTrader: (1)

Detonation det cans | How to knock Muffs