Hey guys,
Ive been getting KR more than i would like... What is pissing me off is, im running 93oct and everything stock engine tuning wise.. Only Tranny Changes.

Still gettin KR.. I know most of it is False KR because its comes on and then slowly goes away. On actually KR it will show its self and go away quickly..

2002 PCM btw Should i put my 00pcm in there and see what happens?

Thanks guys!

dc_justin im goin to send you a Email shortly.

 

Coming on and then going away doesnt necessarily signify that it is false. It could be that you've just moved beyond the load region that is causing the knock to occur. The amount of KR you see is what the PCM has needed to remove from the run spark in order to silence the noise it picked up on.

What rpm and g/cyl does this knock occur at? What's your AFR at that point?

 

Here is a quick and easy way to detect false kr.

Crank up the decay rate.

Engine > Spark Control > Spark Retard > Knock Retard Decay > Decay Rate

The decay rate is the rate of which knock retard is removed in the absence of further knock.
So by turn this up (a bunch), false knock will be seen as one spike of kr were as real kr will be seen as a few spikes in a row. Now with the decay rade on you will also beable to "feel" the timming be added and pulled at WOT if you have kr..........


Normaly the decay rate is somewere between .01 to .016, cranck that sucker up to around .80.

 

LMAO...dc_justin hates the decay cranked up. He's a decay hater. LMAO.

It won't necessarily "tell" you it's false, theoretically you can have real kr for just a "blip" but IMO, it makes for searching for real kr a little more easy. There are pratical reasons to have a low decay, like if you live in cali and have crappy gas all the time, I may be on the fence, but it easier to tune for kr/spark with the decay rate raised IMO.

btw wilde, he's has EFI, table B6207 I think.

 

Fixin to make some runs and log them.
It gets annoying goin down the interstate cruising at 70 and seeing 1 and 2*KR every now and again!

 

post screen shots and/or the scan!!

 

ROTFLMAO, O my god dew, that new sig of yours is killer. LMAO!!!!


Ya I guess I should have mentioned that by cranking up the decay rate and only seeing one spike (in the graph) doesn't meen its fake , it could be real, just less liklly imo.

 

My stock 2000 5.3 shows up to about 2 degrees of KR. Im running 93. But it only comes in at WOT especially in 2nd gear at high rpms. I can sometimes hear it and sometimes ill hear it and it wont show it. The plugs look fine.

I rember someone saying that bits of carbon can come loose and bounce around in the combustion chamber?

I can be at 15 20 miles an hour and put it in 2nd while going up a steep hill and get no KR. It only comes in at WOT.

What I dont get is if there is more load on the engine like in 2nd gear instead of 1st why is there more knock? Shouldnt there be more likely to knock at lower rpms?

Why is the load on the enigine not always the same as long as you are in the same gear and on flat ground?

 

Even if the load is the same the spark advance will vary by rpm so at the lower rpm's you may be running less advance and won't run into KR. I was having the same problems with my 03 until I desensitized the sensors a little and bumped up the Delta cyl air threshold. I was told it tends to be very conservative on the trucks. After doing that I was able to raise the spark table some and not see or hear much if any KR. I have been running in SD mode for the last few days, making logs to and from work and everything seems to be working good. I can wait until my wideband shows up so I can do a better job of dialing in the fueling.

 

Nah, I hate detonation. If the knock sensors pick up real detonation and the PCM uses that various level of KR to quell it, I don't want it to pick right back up again cause the decay rate is too rapid.

That said, mine isn't stock either, just not radical like you.