random knock????????
04-26-2005, 09:20 PM
#1
TECH Resident
Thread Starter
random knock???????? anyone ever heard of it? Im using HPtuners and i have to say its a freaking sweet program, tells you everything. I did a few logs the other night and it seemed like every 3rd log or so i would get a little knock, did a log from a 10mph roll and it did it from 3000-5256 rpm and then nothing after that, did another log and it was just fine, no knock, did a log from 70 mph, and it started at 5149 and lasted till i let off after it shifted into the lext gear and stopped when i let out of it at 93 mph last one i did was from a 25 mph roll i got .4 on the knock retard thing and it dropped the timing from 21 to 8 and it was all over the place, then the knock finially smoothed out at 70 mph at 5057 rpm. so what i have deturmined from the 6 logs that i did tonight that everytime i go WOT then it knocks like a ****........... is there a way to fix this? HELP ME 
04-26-2005, 10:30 PM
#2
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I believe that once you start to knock, the excess heat
can "lower the bar" for more.
Speaking of heat, I hope you have adjusted your fans
to get consistent coolant temp before starting to tune.
Because the stock settings are so stupid hot, you can
see coolant temp swing by about 20-30 degrees based
on load and radiator airflow. This can affect ping and
total timing, adding a "history effect".
Oiled filters can affect the MAF calibration as oil gets
on the MAF elements and changes their thermal
characteristics as crud builds up. You should clean
yours if you haven't already. Lean MAF error increases
timing and shorts you fuel.
Timing moving wildly is abnormal. The only time I've
seen it really jump is on a truck with an intermittent
ECT sensor connection. IAT and ECT have spark effect.
Bad data there can drive the computer nuts. ECT also
pushes on fuel. Look for something that tracks the
spark jumping if you think the spark is unstable (i.e.
not a simple spark advance curve - any observed KR).
can "lower the bar" for more.
Speaking of heat, I hope you have adjusted your fans
to get consistent coolant temp before starting to tune.
Because the stock settings are so stupid hot, you can
see coolant temp swing by about 20-30 degrees based
on load and radiator airflow. This can affect ping and
total timing, adding a "history effect".
Oiled filters can affect the MAF calibration as oil gets
on the MAF elements and changes their thermal
characteristics as crud builds up. You should clean
yours if you haven't already. Lean MAF error increases
timing and shorts you fuel.
Timing moving wildly is abnormal. The only time I've
seen it really jump is on a truck with an intermittent
ECT sensor connection. IAT and ECT have spark effect.
Bad data there can drive the computer nuts. ECT also
pushes on fuel. Look for something that tracks the
spark jumping if you think the spark is unstable (i.e.
not a simple spark advance curve - any observed KR).
04-26-2005, 10:44 PM
#3
TECH Resident
Thread Starter
actually, I didnt adjust the fans.... but all I messed with is the trans settings... base shift pressure, max pressure, and shift timing. I am going to though... but im going to adjust the fans for the stock stat. (what settings would you set the fans for the stock stat??)
I have a paper filter, so no oil on the MAF.
If I adjust the fans, with the computer relearn so it will not hold the KR.
And, about the timing, it dips at the exact moment the KR comes in.... then comes back up, but the spark line looks like a worm...
thanks Jimmy
I have a paper filter, so no oil on the MAF.
If I adjust the fans, with the computer relearn so it will not hold the KR.
And, about the timing, it dips at the exact moment the KR comes in.... then comes back up, but the spark line looks like a worm...
thanks Jimmy
04-26-2005, 11:01 PM
#4
TECH Resident
Thread Starter
here is the graph, see the knock and the timing??
click here
http://putfile.com/pic.php?pic=4/11522595890.jpg&s=x2
click here
http://putfile.com/pic.php?pic=4/11522595890.jpg&s=x2
04-27-2005, 09:10 AM
#5
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What you have there is tip-in ping; see rising TPS,
an immediate "lean hole" in the O2 sensor output,
and spark knock driving KR is the result. The root
cause is an over-lean VE table (change in MAP
reverts you to pure speed-density tune until it gets
back to stable).
The way I fixed this on my car was just to look at
the MAP*RPM where I would get these events, and
increase the VE table at that cell by a couple of
points followed by "eyeball smoothing" to bring the
cells nearby up to a reasonable smooth looking fit.
I never got too fired up about the whole-hog SD
tuning, but a little adjusting of the VE table will
squash that tip-in ping and improve transient throttle
response. Ideally you would like to see the O2s rise
slightly on tip-in rather than dip. Then you can go
and maximize spark advance.
Your .sig says K&N....
an immediate "lean hole" in the O2 sensor output,
and spark knock driving KR is the result. The root
cause is an over-lean VE table (change in MAP
reverts you to pure speed-density tune until it gets
back to stable).
The way I fixed this on my car was just to look at
the MAP*RPM where I would get these events, and
increase the VE table at that cell by a couple of
points followed by "eyeball smoothing" to bring the
cells nearby up to a reasonable smooth looking fit.
I never got too fired up about the whole-hog SD
tuning, but a little adjusting of the VE table will
squash that tip-in ping and improve transient throttle
response. Ideally you would like to see the O2s rise
slightly on tip-in rather than dip. Then you can go
and maximize spark advance.
Your .sig says K&N....
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04-27-2005, 12:11 PM
#10
TECH Resident
Thread Starter
Originally Posted by jimmyblue
What you have there is tip-in ping; see rising TPS,
an immediate "lean hole" in the O2 sensor output,
and spark knock driving KR is the result. The root
cause is an over-lean VE table (change in MAP
reverts you to pure speed-density tune until it gets
back to stable).
The way I fixed this on my car was just to look at
the MAP*RPM where I would get these events, and
increase the VE table at that cell by a couple of
points followed by "eyeball smoothing" to bring the
cells nearby up to a reasonable smooth looking fit.
I never got too fired up about the whole-hog SD
tuning, but a little adjusting of the VE table will
squash that tip-in ping and improve transient throttle
response. Ideally you would like to see the O2s rise
slightly on tip-in rather than dip. Then you can go
and maximize spark advance.
Your .sig says K&N....
an immediate "lean hole" in the O2 sensor output,
and spark knock driving KR is the result. The root
cause is an over-lean VE table (change in MAP
reverts you to pure speed-density tune until it gets
back to stable).
The way I fixed this on my car was just to look at
the MAP*RPM where I would get these events, and
increase the VE table at that cell by a couple of
points followed by "eyeball smoothing" to bring the
cells nearby up to a reasonable smooth looking fit.
I never got too fired up about the whole-hog SD
tuning, but a little adjusting of the VE table will
squash that tip-in ping and improve transient throttle
response. Ideally you would like to see the O2s rise
slightly on tip-in rather than dip. Then you can go
and maximize spark advance.
Your .sig says K&N....
I cleaned the MAF, not dirty at all... a while ago, then put my stock filter back in
can you please explain the steps in adjusting that MAP RPM, VE step please. im really new to this
thanks so much...
04-27-2005, 12:13 PM
#11
TECH Resident
Thread Starter
Originally Posted by RedHardSupra
do you have a stiff suspension? I get phantom knock sometimes, but after 3 months of chasing it, i'm thinking that's just my stiff suspension making noise.
the ORY bangs... but its making my timing really nasty, so I dont think its false knock. thanks though
04-27-2005, 12:43 PM
#12
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knock retard? thats not knock retard, let me show you some knock retard lol
I wish that was all the knock retard I was seeing lol try 11 deg any time I hit 3500 rpm with 75%TP or more. This C5's tune was so wacked out I do not know what the previous owner was thinking.
More Than Zero
I wish that was all the knock retard I was seeing lol try 11 deg any time I hit 3500 rpm with 75%TP or more. This C5's tune was so wacked out I do not know what the previous owner was thinking.
More Than Zero
04-27-2005, 12:50 PM
#13
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Look at the logs (I prefer using the .csv exported
file in Excel). Find the place where KR jumps up.
In the preceding frames you should see an increase
in TPS and a dip in O2 voltage. At this point note
the MAP reading (kPa) and the RPM.
Now go to the Primary VE table in the Editor. At that
MAP and RPM is a value (%) for volumetric efficiency.
If your O2s dip then it's too low. If your O2s jump on
rising TPS% then it's too high. In your case, low. Up
the value there and look at the neighbors. The 3D
surface view is nice, here. If you just made a spike
then you want to go back to the table view and bring
the neighbors up to "smooth" the surface. Don't want
to use the auto-smooth as this will tend to squash the
new "spike" rather than raise the neighbors. Flip back
& forth, until you like the looks of the surface. The
airflow should not be "jerky" as RPM or MAP change
incrementally, so neither should the VE table. Not unless
you have some freak resonances. Some people who do
the SD tune seem to end up with slightly better trims
etc. with odd / lumpy tables but I believe this is two
wrongs making a right, like.
LTs -should- raise your VE from midband on up and I
guess nobody ever told the computer. You might take
a guess at the torque increase as a percentage (like
+30 lb-ft would be maybe 8%) and apply a 1.08 mult
scaling to the VE table above 2400RPM, 1.04 at 2000
and see how that looks.
Here's a stock VE map (3D surface view):
Here's my current table (just gutted cats etc. but no
tip-in p ping:
And here's a table that ended up being a pretty good
driver for a TRex H/C car, just for comparison - see how
the cam kills VE down lower and builds it up, up top:
file in Excel). Find the place where KR jumps up.
In the preceding frames you should see an increase
in TPS and a dip in O2 voltage. At this point note
the MAP reading (kPa) and the RPM.
Now go to the Primary VE table in the Editor. At that
MAP and RPM is a value (%) for volumetric efficiency.
If your O2s dip then it's too low. If your O2s jump on
rising TPS% then it's too high. In your case, low. Up
the value there and look at the neighbors. The 3D
surface view is nice, here. If you just made a spike
then you want to go back to the table view and bring
the neighbors up to "smooth" the surface. Don't want
to use the auto-smooth as this will tend to squash the
new "spike" rather than raise the neighbors. Flip back
& forth, until you like the looks of the surface. The
airflow should not be "jerky" as RPM or MAP change
incrementally, so neither should the VE table. Not unless
you have some freak resonances. Some people who do
the SD tune seem to end up with slightly better trims
etc. with odd / lumpy tables but I believe this is two
wrongs making a right, like.
LTs -should- raise your VE from midband on up and I
guess nobody ever told the computer. You might take
a guess at the torque increase as a percentage (like
+30 lb-ft would be maybe 8%) and apply a 1.08 mult
scaling to the VE table above 2400RPM, 1.04 at 2000
and see how that looks.
Here's a stock VE map (3D surface view):
Here's my current table (just gutted cats etc. but no
tip-in p ping:
And here's a table that ended up being a pretty good
driver for a TRex H/C car, just for comparison - see how
the cam kills VE down lower and builds it up, up top:
