fed up with knock control
Nov 6, 2008, 03:35 PM
#212
But anyway, yeah, misfire is just a break-up type feeling...can't really describe the sound. At idle, it's more of a stumble/sputter. In boost, it's more of a tug, like Bryan said, all the way to a fuel cut type feeling like I described, if it's bad enough/prolonged enough.
Last edited by l2r99gst; Nov 6, 2008 at 03:41 PM.
Nov 6, 2008, 05:22 PM
#215
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It sounds like two rival gangs are shooting each other up in the back of your car. If you have a good wideband you can sometimes pick this up.
Whereas fuel cut causes your knees to hit the dash of the car. If your not wearing a seat belt like you should you will probably end up with a broken and bloody nose. You'll see the IPW in your logs drop to zero.
Just to exercise this to the extreme. Breaking up is like a soft rev limiter. I usually refer to breaking up when you have a mechanical issue such as valve float, valvetrain parts (usually springs) going harmonic, or just plain old you broke ****. You can see the airflow drop off or taper off where it shouldn't be. Also torque will take a nosedive on the dyno when you shouldn't be falling off a cam or out of a intake manifolds working range.
I know it seems silly, but it has taken me years to learn this the hard way with nobody around to help me.
Nov 6, 2008, 08:25 PM
#218
So Dave, this 0% to 100% 3D map of yours...
If you set it to 50%, if you get 4 counts of knock the ECU will only see it as 2 counts correct? And if you set it to 0% it won't see ANY knock even if its present, regardless of the knock count?
It seems as though the trailing edge of the knock occurance where it slowly tapers off is just the ECU's decay process and not real knock, am i right in assuming that? In that instance, if i had the table set to 0% up to a certain point and when I re-engaged the knock in the next cell at 100% and it was in the 'decay' portion of the knock count...would it see it as true knock? I hope that made sense lol.
If you set it to 50%, if you get 4 counts of knock the ECU will only see it as 2 counts correct? And if you set it to 0% it won't see ANY knock even if its present, regardless of the knock count?
It seems as though the trailing edge of the knock occurance where it slowly tapers off is just the ECU's decay process and not real knock, am i right in assuming that? In that instance, if i had the table set to 0% up to a certain point and when I re-engaged the knock in the next cell at 100% and it was in the 'decay' portion of the knock count...would it see it as true knock? I hope that made sense lol.
Last edited by Jack_of_Trades; Nov 6, 2008 at 08:29 PM.
Nov 6, 2008, 08:34 PM
#219
yeah but only for the timing/ignition routines.
so octane will still happen (2 consecutive 6KS+) and any fuel dumps will still happen.
edit - answer to your edit :
Well if the ECU is decaying the knock and you go 100% in the table then timing will get pulled like normal...
This 3d table should ONLY be used for when the knock is phantom AND impacting performance.
Standard disclaimer as usual
so octane will still happen (2 consecutive 6KS+) and any fuel dumps will still happen.
edit - answer to your edit :
Well if the ECU is decaying the knock and you go 100% in the table then timing will get pulled like normal...
This 3d table should ONLY be used for when the knock is phantom AND impacting performance.
Standard disclaimer as usual
Nov 6, 2008, 08:57 PM
#221
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I can definitely say my car is not misfiring when this happens. Retarded timing actually smoothes out the motor, so the reason why it shows up as knock has got me stumped. My car is an auto, so there is no clutch rattle either. There are no weird noises, it runs the stock exhaust back to the diff, and nothing is loose anywhere.
Nov 7, 2008, 02:50 AM
#223
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The usual, around 3000rpm and around 100 load. It jumps almost straight to 36 knock sum. 150% for certain it is not knocking and there is nothing wrong with how the motor runs other than the lack of power due to the retarded timing.
I am really trying to wrap my head around what the ecu looks for. Could there possibly be something that will ignore looking for knock if the timing is above a certain number? Maybe the more retarded the map timing the more sensitive it becomes? Has anyone found the load above which knock control starts working, or is it infact load that triggers it to start?
I am really trying to wrap my head around what the ecu looks for. Could there possibly be something that will ignore looking for knock if the timing is above a certain number? Maybe the more retarded the map timing the more sensitive it becomes? Has anyone found the load above which knock control starts working, or is it infact load that triggers it to start?
Nov 7, 2008, 07:21 AM
#225
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I completely disabled my knock sensor while waiting for this patch from Tephra...not having the random 30+ counts of knock at 3500 made me fall in love with my car all over again, I can't stress enough how much better the car feels for daily driving. I can't wait to get control over that one section AND still be able to log knock