Tin Indian

The 98s seem to get alot of knock retard compared to later year cars. (3 to 4.5 degrees with good gas and no banging exhaust parts)

Just wondering if LS1Edit can de-sensitize these overly active 98 knock sensors?

Thanks,
Ron

Bink

According to Ken Kelly they can't be desensitized with edit. But you can change what the PCM interprets as Knock. Do a search of the LS1edit.com archives (google it), It was discussed in the past two months. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Tim Sloper

The sensors themselves cannot be "desensitized" but you can directly control the PCM's response to knock sensor activity with LS1Edit. Be absolutely sure the knock is not real before modifying the KR tables.

Tim

glitch77

What are your LTFTs? My 98 was knocking pretty bad throughout the RPM band, but I was running way lean. 12+ LTFTs. Got me a MAFT and fixed it all. You could use Edit to do the same, if thats the case.

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Tin Indian

Kinda hard to read this, but the LTFTs (LTB2 & LTB1) were mostly zero
_____________________________________________

RPM * TPS * Gear * LTB2 * LTB1 * O2B2 * O2B1 * O2/Avg * Retard * Timing

3320 100 1 5.5 2.3 .835 .890 .863 .0 25.0
4297 100 1 .0 .0 .835 .905 .870 .2 25.0
4909 100 1 .0 .0 .845 .915 .880 1.2 25.0
5988 100 1 .0 .0 .840 .905 .873 3.3 24.0
6065 100 2 .8 .8 .700 .880 .790 3.3 24.0
5226 100 2 .0 .0 .860 .915 .888 3.1 24.0
4909 100 2 .0 .0 .865 .915 .890 2.9 24.5
4279 100 2 .0 .0 .865 .925 .895 2.7 25.0
4273 100 2 .0 .0 .860 .915 .888 3.9 24.5
4478 100 2 .0 .0 .860 .910 .885 3.9 24.5
4672 100 2 .0 .0 .870 .905 .888 3.8 24.5
4872 100 2 .0 .0 .870 .905 .888 3.6 25.0
5072 100 2 .0 .0 .870 .915 .893 3.3 25.0
5284 100 2 .0 .0 .875 .910 .893 3.1 24.5
5476 100 2 .0 .0 .880 .905 .893 3.0 26.0
5647 100 2 .0 .0 .880 .905 .893 2.9 25.5
5834 100 2 5.5 .0 .895 .905 .900 3.8 24.5
6038 100 3 .0 .0 .890 .900 .895 3.9 25.0
5610 100 3 5.5 .0 .895 .915 .905 3.6 24.5
5695 100 3 1.6 .8 .900 .925 .913 3.4 25.0
4258 100 3 1.6 1.6 .905 .915 .910 4.0 24.0
4284 100 3 .0 .0 .900 .905 .903 3.9 25.5
4398 100 3 .0 .0 .890 .905 .898 3.9 25.0
4465 100 3 .0 .0 .895 .900 .898 3.6 25.0
4528 100 3 .0 .0 .890 .900 .895 3.9 25.5
4606 100 3 .0 .0 .890 .905 .898 3.8 24.5
4666 100 3 .0 .0 .900 .905 .903 4.0 24.0
4746 100 3 .0 .0 .890 .900 .895 3.7 24.5
4814 100 3 .0 .0 .885 .900 .893 3.9 25.0
4876 100 3 .0 .0 .890 .890 .890 3.9 24.0
4937 100 3 .0 .0 .895 .895 .895 3.7 24.0
4999 100 3 .0 .0 .890 .905 .898 3.4 25.0
5060 100 3 .0 .0 .890 .895 .893 4.0 24.0
5125 100 3 .0 .0 .895 .885 .890 3.9 24.5
5189 100 3 .0 .0 .885 .900 .893 4.0 24.5
5253 100 3 .0 .0 .885 .895 .890 3.7 25.0
5296 100 3 .0 .0 .890 .895 .893 3.5 25.5
5361 100 3 .0 .0 .880 .895 .888 3.5 24.0
5419 100 3 .0 .0 .885 .890 .888 3.3 24.0
5480 100 3 .0 .0 .880 .890 .885 3.9 24.0
5523 100 3 .0 .0 .880 .890 .885 3.8 24.0
5589 100 3 5.5 2.3 .900 .885 .893 3.6 25.0
5635 100 3 1.6 .8 .885 .890 .888 3.4 24.5
5686 100 3 .0 .0 .880 .895 .888 3.9 24.5
5736 100 3 .0 .0 .890 .890 .890 3.6 25

<small>[ April 21, 2003, 04:14 PM: Message edited by: Tin Indian ]</small>

parish8

iTrader: (6)

i was able to edit how quickly the computer reacted to knock and also recover from knock more quickly but if you have continuas false knock like i did it wont help. after trying for hours with ls1edit i gave up and just put some resistors inline with the knock sensors. cost me 20cents and works great, no more false knock but if i up the boost or toss in some bad gas the sensors still work.

Bink

parish8- Why resistors? I mean I know to bump resistance but Why? Does this in effect reduce the sensitivity of the sensors?Seems like it would??I never would have thought of this . <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> Too Cool (or as we said years ago "That's TUFF") <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Bink

ttt

Scalpel

iTrader: (4)

Can you tell us how you did this? Thanks.

Bink

I Agree.

parish8

iTrader: (6)

i just tossed a 10k resistor inline with each knock sensor wire, i am not sure how those things work but i imiagne that they produce a voltage when they hear knock and puting a resistor inline will reduce the voltage that gets to the computer.

if you put to high of a resistor inline i think your computer wouldn't be able to see the sensor and would cause a code, if you go too small than it won't have the desired effect. i can't remember how i came up with 10k but it seems to work. i have had them in there for months and haven't seen any codes and here is what i have seen as far as knock retard.

no resistors, 6psi, pump gas> burst of KR at launch and shifts that never had time to go away, 4-8deg
10k resistors with 6psi, pump gas> no KR, no codes
10k resistors with 8psi, pump gas> full 8deg of KR thru entire run
10k resistors with 8psi and 100octane> no KR
10k resistors with 11psi and 100octane> 6-8deg at launch that tapered thru the run

with those results i appear to have working knock sensors, no codes and no more false knock. i had a serious problem with KR and tried alot of things to get rid of it, cooler stat, electric fans, opened up the exhaust, good gas. it wouldn't go away, now with 2 10cent resistors the truck is running like mad.

i adjusted the "attack vs rpm" and the "decay vs rpm", it looks to me like those 2 charts should slow how quickly it pulls timing and allow it to go back more quickly but i could be wrong about that. i didn't have any luck working with these charts but i blamed it on continuas false knock and the charts not being able to help if the knock is continuas but i may just not understand what the charts are for.

Bink

parish8 - Thanks man for the solid info!!! Great old American ingenuity!
Joel