lt1 $ee knock retard caused by echo?

[zoomo]

I've struggled with this issue for a while. Before I had stock rockers, now I have roller tip rockers and it still happens.

It just absolutely seems echo related. It happens at the drag strip and on the dyno. I can even get it to do it going past a bridge and accelerating. Yet when there's nothing to cause an echo I don't get spark knock.

I torqued the sensor down , but it was some kinda cheap (40) orielly thing or something. Thanks for the help guys.

[SSlowBoat]

What do you mean an echo, I've never ever heard of that. Have you detuned the knock sensor values?

[popo8]

I think he means when sounds resonate back. Like drivin a car with exhaust through a tunnel amd the amplification is whats make the viberations strong enough to read knock. Im not sure how feasible that is.

[SSlowBoat]

I understand that. I don't understand how an echo from way outside the car could cause a knock sensor issue with all the vibration and jingles and Ltx powa noises going on. Maybe MoeHorsePower or nate could shed light on this?

I'm thinking more along the lines that it is coincidental. Op, do you have any data logs of the car doing this? I'd like to see them if so.

[zoomo]

it seems unlikely to me as well, especially with all the valve train noise that it doesnt seem to hear but it just seems like thats what happens ha. i havent messed with the knock sensor specifically in anyway but i have tuned the timing a lot.

All my logs and stuff are in tuner pro, here are some at the drag and on the dyno and a normal driving one that im sure has some wot in it. also my current tune.

It seems very strange to me and youre probably right , its just coincidental and something else is happening at that moment as well that im missing.

Also as im looking at these over and over, im realizzing it may be when my temp is rising a bit cause its reading like 240 on the log, though the conversion is off so that s really like 200? not sure



well crud i cant upload .bin files or .xdf? what am i doing wrong?

heres a link to my post on gearhead where my files are listed if that helps

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?4144-Tuning-ee-lt1-spark

[popo8]

If u take some of the sensitivity out of the knock that may help u then....

[zoomo]

If u take some of the sensitivity out of the knock that may help u then....

man you guys are the best ha, i didnt think that was a possibility, reading about it now, so far i found this
"1.) Knock Fast Attack(Higher number means a more aggressive KR)
2.) Knock Recovery Rate (Higher number means the faster the KR will be removed)

1.) try lowering a little bit at a time. Normally it shouldn't take more than 15% - 20% to remove the false knock.
2.) For the second part, this wont actually desensitize the sensor, but help you bring in your if you do get false knock. This table will determine the percentage of timing to be put back in, per 8 cam pulses. So in turn, raising this number will put the retarded timing back into the motor more aggressively. "

ill keep reading, anyone feel free to jump in :hail:

[popo8]

Im a tuning idiot and only know the basic talk. Never actually hands on without supervision.

[zoomo]

lol i wish i had some supervision but im in this on my own. Thats ok though its been a fun ride, learning new stuff constantly, i think that we are definetly on the right track here

[SSlowBoat]

All my tunes have it locked at 3-4 degrees na and boosted is 2 but I tuned the timing tables with the help of others to not allow it to use that 2 as a safety in boost. Factory pcm I think is 10 degrees which Is nuts lol

[zoomo]

All my tunes have it locked at 3-4 degrees na


Do you mean max knock retard? i have mine set at five, i will lower it some maybe to 3. I dont think this is real knock retard, ive never heard the car clatter and cant imagine that it would be with the set up and timing.

still kind of confused about tuning the knock attack and recovery rate though i guess i will try adusting both and see what happens :confused:


Edit: well i found a little more info on tuning these tables on hp tuners, although of course some things are different, so i may have went too far.

i ended up adjusting the fast attack rate 10% lower (it was already adujust lower by nearly 20% from stock) so thats 30% lower in all on the fast attack rate

my understanding from reading and logic is that the "fast attack rate" is the rate in which the timing is reduced?
although im not sure, it seems to be a confusing subject as some people say exactly the opposite ha.

i also doubled the recovery rate, this seems pretty straight forward by the name. I'm assuming this is how fast it removes the knock retard?i read that was ok, though a lot of the things i read said adjust it by slight amounts.

ive also found some stuff about adjusting the low octane table, and some talk about the decay tables, but i havent done anything with that stuff yet.

My max retard was at five, i also lowered it to 3 in both tables.

im slightly confused about the terminology of the knock recovery table, and the fast attack table, because i guess really they could need to be adjusted opposite of what i did, if im mis-understanding the description.

thanks for all the help and advice as always guys, im gonna load this tune up shortly and see if it changes anything, although unless it makes things worse i probably wont know until i hit the drag strip next week.

Last time i was there trying to tune out random spark knock i had to get towed home cause i killed my pcm, i guess this time ill take a jump box and my spare pcm haha

[zoomo]

Just in case anyone needs this information in the future heres what ive figured out so far

After doubling the recovery rate, it caused the knock retard to stay for a very very long time. After it picked up any knock it would continue to pull timing for about a minute every time i would accelerate even a little.

So i cut the knock recovery rate back to stock, then cut it in half, this seems to be good, if not too good on the knock recovery. it will pull the timing and actually start to add it back in within a couple second, which isn't particularly a good thing if you are encountering significant, real spark knock, but for tuning purposes it kind of helps you find where your knock is occuring. I think i will leave it here.

Now for the fast attack, i left this alone, adjusted at 30% lower than stock until the testing with the recovery rate was done. i adjusted this back to stock, then 30 % higher than stock, and at this point i am not getting any knock retard where i was.

Although it is night time now, so the air is cooler, could just be that but i will continue to test it, and add timing back in if it continues not to get knock.

im running tuner pro , im not sure how these adjustments will work on anything else.

on another note, im getting about 4 degrees of weird advance at wot, like i have to have it set to 26 to keep it at 30 and it climbs to 31 at 4k for some reason.. even though im set at 26 from 2600 rpm on.

Ill let yall know if i find any thing else. and hopefully this is what my problem was and i was just imagining the "echo" spark knock lol

[SSlowBoat]

I think you found your problem. Nice work.

[zoomo]

Are you thinking it was the attack rate?