198d F coolant

31 d SA when KC appear

non AE non PE
accellerate onto Xway brisk from stand stop into 2nd gear.

At 23 mph 32 MAP 2800 rpms I got a sizable KC of about 500.
changed gears(stick 2 to 3) then maxed KC at 2800 rpms.

93 octane
10.0/1 CR 64 cc EDEL RPM alum heads(newer version on chamber I believe in 2003).

Prob mechanical noise.

Original K sensor 25 years old ! Any reason to swap out due to EBL-ECU.

 

ttt

 

I have an '89 vette. I installed a knock module from a 4.3 Caprice, which is suppose to be less sensitive than any other module, including the LT4. It helped but still have tons of knock retard no matter where the timing and fueling is set. I think it's a combo of LT headers, loud roller rockers, and Rhodes vari-duration lifters. I ended up cutting the brown wire going into the knock module and putting plugs on it. I plug it in for WOT tuning when I'm looking for major knock areas, but once the tune is worked out and I'm sure it's not real knock, I unplug the wire to disable the knock retard system. No codes or anything appear. If you just unplug the knock sensor you will get a code.

One other thing you can try is to pull out the knock sensor and heavily teflon tape the threads and end of the sensor then reinstall it. It helps to "deafen" the sensor but there is no way of knowing how much you are deafening it. If you do pull the sensor you will likely get an antifreeze bath and will need to burp the system when refilling it, which you may already know.

 

I think the KC which I witnessed today 750 counts all came on a brisk pull onto Xway in traffic. 4000 rpm in 2nd to 3rd. SA is under 30 there. Cruise is like 36. No PE SA in my bin.

I too have headers but i think mechanical is issue with real duals and possibly fitment in tunnel. Custom welded. I will check that. someone said roller rockers can cause same which I have but the engine is quieter at idle with rollers.

As a side note my snowmobile has a K sensor that caused me fits but only when new. Issue went away. 92 octane used there.

 

You are doing better than me then. My cruise SA is set at 32 and I still get some KC's even during cruise. 92 octane. My timing table starts at 26 at idle and tapers up to 32, and I have 3 degrees in the PE SA table. I generally get less knock counts at WOT than I do at part throttle. My valves are LOUD at idle and part throttle though. They slam shut fast due to the Rhodes lifters, and the sound echos up through my HSR custom plenum. It acts like an echo chamber. I have no room to have ribs on top to help deaden the sound.

You could try knocking the timing down to low to mid 20's in that area, make sure the fueling it good or a hair rich, then make the same drive again trying to replicate what you did before. If the KC's are still high you will know for sure it is mechanical issues causing it. Only way I know to fix that is change parts, deafen sensor, or snip the brown wire going into the knock module to kill the knock system.

 

Thanks. I will look at my datalogs to be certain of the rpm/map/SA it is occurring. I have 10 logs to look at. another option you did not mention is to add more octane! they sell race gas a few miles from my home $$$$$$...

I recall when I first started tuning I saw some KC around 3000 rpms 50 map. I pulled 2 deg around that area and it went away 92 octane. then gas was $4 a gal so switched to 89 and it did not reappear. I did not change SA that I can recall in that area. Since I added 2 deg but it is higher map and higher rpm in table. i believe I also have those old bins to look at.