Well, took truck out for spin, just scanning now, just got laptop hour ago.

But things are bad

Seeing 6 degrees of knock.

Here the question, when I look at the 02's whether is be on the gauge display or graph, the O2's are going wild. 102 to 900 back and forth.(at a constant rate though) then when letting off the throttle goes steady for about a second??? normal, I am thinking not.


I figure out how at work today, maybe have some logs to throw up in moring, maybe have you guys look over the cluster @#$@$

Thanks for the advice in advance

CT

 

I would try taking out some timing where you are seeing knock. You could add some 100 octane and see if the knock goes away. Choose one.
Im not sure on the 02 stuff. If it were me and you have some miles, I would just spring for replacement 02's.
How are your Ltrims looking?

 

60k on the truck

Will know more by moring, got to firgure out how making config files for logging.

thanks a bunch for the quick responce.

 

What O2 sensors are you monitoring? B1S1, B2S1? If so it sounds like the truck is not going into PE mode since the sensors are still switching. Have you ever checked to see if your throttle blade opens all the way at WOT, not sure if that was ever a problem on the 8.1's but, it'd be worth checking out.

The going flat for a second after letting off the throttle is pretty normal. Mine drop like a rock after letting off from a WOT blast. It's from the DFCO(deceleration fuel cut off) kicking in. The sensors will show REAL lean for a second before they pick up and start switching again.

I'm assuming the 8.1 management is pretty much the same as the LS variants.

 

Its probably false knock. Mine showed 5deg anytime I went to WOT no mater what gas I had in it. The O2 should bounce back and forth until WOT then it should go to the rich side and stay their until you let off. But mine did the same thing it was a little lean.

 

Oh, I forgot to say something that might be causing the knock. Have you ever did a top end clean on your engine?

I used to get a few degrees of knock no matter what I did with the fueling or timing until I sprayed a can of top engine cleaner in the engine. My truck had about 100K on it at the time and always uses about 1-1.5qts of oil in 5-6K. I did the top engine cleaner and put a PCV oil catch can on and since then don't have any knock.

If you find out it's not false that is something to try.

 

Did some tuning today, end adding fuel three times, or else I am not doing something right here. but midrange is starting to pick-up though. ltfts are way ++++ I have yet to bring them down under +5, which the goal is 0 or -2. still get knock at 2800 to 3200 rpm with good load on it (some throttle)

Question when writing to the pcm, it usually go that quick?? roughly around 27secs here.