Dude i hit a random knock sum of 43

[TERBOLASER]

Dude i hit a random knock sum of 43 !!! last night racing a BMW. never happened before seemed odd my fuel trims are wierd high is 98 like normal and middle is 99 but low fuel trim was at 81-88 percent horrible fuel trimfor low i know. The knock sum happened just through the 5000 rpm range and went back to normal at like 5939. i cnat seem to recreat the situation did several runs after wards cautiously watching the the laptop logger. while throwing gears down thru third and the knock sum line moved the normal 1-3 knock the entire time nothing close to 43 knock!!! whats up ne ideas o yea and now just happened previously to this my car doesnt hold an idle after letting of the gas hard. the tach need drops faster than a brick of the empire state building. ne ideas?

 

[kpt4321]

Is your BOV vented to atmosphere? Also, check for boost leaks.

If you can't recreate the knock, then don't worry about it.

That low fuel trim isn't that bad, but it could be better. If you're running some kind of fuel control, lean the idle out a couple percent.

 

[thejeebus]

I would guess one or more lifters acting up. I wouldn't worry about it honestly. Mine are giving me a hella time right now on startup in this colder weather.

scott

 

[btrux06]

lifter probably just got real loud and made all the false knock , it happens sometimes to me

 

[TERBOLASER]

Lifter noise being loud on a new motor with under 40k on it? I dont get any lifter click on idle at all. sounds perfect when I run it to
I checked it ou and I noticed its only on my low throttle but never at wide open throttle. I looked at my fuel trims and my middle and high fuel trims are at 100 percent perfect fuel trims but my low fuel trim fluctuates from 119% down all the way to 81 percent and is always changing. The only time I get knock is at the start of the race at launch
and then knock goes away as I push wide open throttle.