T/A rocker

Been trying to tune it out with LS1Edit, and no luck.
1. My LTFT's at load are slightly negative, and locked @ zero when WOT. I got them neg. by scaling IFR by 91% .
2. Timing advance is stock.
3. I have Scaled the PE table anything from 101% all the way to 110% with no effect on the KR.
It is when WOT, the KR starts at about 3750 RPM, and continues until about 5000 or so RPM. Values of KR from 1.2 min. to 3.9 deg. max, the max usually at about 4250 RPM. Timing at WOT is about 30 deg. until the KR kicks in, there is a dip in my timing, down to about 24 deg. from 3750 to 5000 RPM, then of cousre it rises again as the kR drops off over 5000.
I know 02's don't mean much at WOT, but they are about .920 @ WOT with PE stock, and about .940 with PE scaled 110%... so surely it is not going lean?
I have run Seafoam through the engine several times to try and eliminate carbon buildup as a possibility.

I don't get it. Could it be false knock? What do I do? I want rid of it !!
Of course I could desensitize the knock sensors through Edit in the "attack vs RPM" tables, but I could seriously screw my motor up too!
Please, any suggestions? I don't know what to try next ????

horist

when did it start? when was the last time you noticed the car was ok and what have you added since then?


Edit: just noticed you have a 98

... there's some kinda weird phenomenon w/the 98s and knock... not sure if this is your problem though... (i believe the fix is to install updated knock sensors) ... the phenomenon I speak of is "the dreaded 3.9* knock " ...

Since you have LS1Edit ... if it were me I would try adjusting my high octane timing tables to lower timing advance say 5* (.60gm/cyl or greater and only at the affected RPMs) and then go WOT .. the car will feel slower than a civic but dropping that much timing w/your mods should eliminate any false knock (unless you're running really lean)

FinalTA

iTrader: (1)

Do you run an oil catch can? Running seafoam will do next to nothing if you continue to get oil contamination...

jimmyblue

iTrader: (11)

30 degrees timing is all I've ever seen on my motor,
and even there it takes a bit of excess enrichment
to cover pinging and I only get that high an advance
value right at 6KRPM. If you have that much, lower
down, then KR doesn't seem out-of-place.

First order, get your logs w/ KR, MAP, RPM. Go to the
timing table and in the (MAP, RPM) cells where you have
KR, subtract the KR amount from the timing value.

If the KR then disappears (or almost) you can conclude
that you just were at the engine's detonation limit given
compression ratio, fueling, temps, etc. To run more
timing you would have to address these factors, if
changing them seems sensible given current AFR etc.

If the KR does not respond properly, you can conclude it
is a false knock, sensitivity or abnormal mechanicals
problem (bent pushrods, bad rocker, bad spring, other
things that are crank-synchronous can trigger knock
detect).

T/A rocker

Thanks for the replies !
FinalTA, yes I am running an oil catch can. I get about a teaspoon a week out of there.
I will try decreasing timing in the effected RPM ranges,if I can figure out the part of the tables to do it in, and see if I am getting false knock.
Not sure what I will do if it is, but it sure be good to know foe sure.
In the RPM's wher I get the KR, I onlt get about 24* of advance, I'd like to get it to 27 or 28, I think power would be much better.
The KR is driving me nucking futs, but with the help from you guys here, I'm sure to figure it out! Thanks a $@&#load !

bomax

iTrader: (3)

You could also throw some high octane gas in there and see if it remains. If it does, it's safe to assume it's false.

bomax

iTrader: (3)

I thought it was G/cyl and RPM, not MAP and RPM?

And the G/Cyl calculation requires MAF, not MAP. Or am I way off?

itchygomey98

iTrader: (2)

If you figure out that it is false knock, you can fix that with LS1edit. On mine, I ended up raising the knock noise level to 1.7 and have had no problems since. From what I've seen, the 98's are very prone to false knock.

bomax

iTrader: (3)

Mine was 1.7 stock....

WS6FirebirdTA00

iTrader: (33)

can you actually hear the knock? what kinda temps is your car running at. i noticed on mine with WOT values all right on the car was just too hot. i put in a 160* stat and took off the egr and i was able to take out some fuel at WOT and runs good. im sure u thought of it but figured i woudl throw it out there. however most of my friends with 98's get false knock

T/A rocker

I don't actually hear anything. This car has had the KR, which happens to frequently be 3.9*, but never over that, for at least as long as I have had Autotap, about two years. The car was stock then except for a lid and GMAF.
I now have a 160 deg tstat, and the fans set accordingly. Usually temps max around 183, 190 at most on hot days when driving hard. I'm starting to believe it's false knock. But going to try and make sure. Then I can adjust for it with EDIT. Wish I knew of some place to get some real high-octane gas around here. There's gotta be some place !

T/A rocker

This is wierd. I just pulled up my PCM file in Edit, and my knock detection noise level is already at 1.7. I've never messed with it! And that was the stock .LS1 file. What gives ?

deezel

Try the local track or performance shop for hi octane fuel.
I think 1.7 is the stock knock noise level. I have seen some report changing it to 1.8 or 1.9 to help with false knock. Do the hi octane test first...
Also, you might check your knock sensors for corrosion or over-torque, which could contribute to false knock readings.

Bill Bowling

iTrader: (6)

I am having the same problems with KR. I have already tried octane booster with no help. The knock sensors are under the manifold aren't they? That would make it a little hard to check for corrosion or am I wrong?

Bill

itchygomey98

iTrader: (2)

Woops! You're right. I looked at the wrong file. I'm at 1.9 now. Sorry for the confusion.

samz28

toluene. sherwin williams, drop two gallons in at fillup or 100% xylene.

you can do 20% toluene and 10% xylene, if your shiz still knocks you got some messed up stuff.

10% toluene should bump ya up a few octane if you are not going a full fill up, just give it a day or so to mix up.

i'd say get it empty, pump in 1 gallon toluene and then 5 gallons 93/94 octane.

if the knock goes away, well that sucks, you have to run more octane or less timing.

all sherwin williams or whatever you call the "business paint" stores sell 100% xylene or 100% toluene.

jimmyblue

iTrader: (11)

Maybe you're right, it might be the g/cyl as an index (which
would be the Dynamic Cylinder Air PID). I'm 2000 miles away
from my car & tuning laptop right now