New Cat-back and Cat converter, now new knocking...

[Drewcool2]

Just installed my thermal research cat-back, and catco high flow cat converter. Overall I got some nice gains over stock. But now I have a problem. When I floor it accelerating above 5K RPMs, I get mild spitting, and miss-firing. I never noticed this problem until I put my exhaust on. I don't know if its a coincidence...
But I hooked up my logger, just to see how my ignition timing is all over the place. Also, it doesn't appear to be running too lean. My O2 sensor readings stay around .8800-.9300V. (Or is that bad?)

What causes my ignition timing to change so much? Even at idle, looking at a graph, my ignition timing is jumpy. I'm assuming this is related to my high rpm miss-firing.

I have new msd coil pack, wires, and NGK plugs.

 

[RipperXX]

Do you have any way of telling how rich or lean you are runing at WOT? I dont think the computer takes the O2 readings into account at WOT, or am I wrong?

 

[Drewcool2]

Well im taking the O2 sensor readings using my datalogger while i'm at WOT, so I can see how rich or lean it is running. I want to hookup a permanent air/fuel gauge soon. Much easier.
But doing it this way, i think stoich is at like .9200V or something. So anything above that is too rich, and anything below that is too lean.

I still want to know about my ignition timing though.

 

[RipperXX]

Well the only reasion I said that was becouse I thought the computer went to a closed loop fuel map when it was at WOT and didn't think the computer adjusted the fuel map by the O2 sensor.

Sorry about your timeing, I dont have a clue what is causeing that. Possibly a bad cam sensor??? I dont realy know there. Maybe some one else can help on that.

 

[RipperXX]

Just happened to think, if you have a silancer that came with that exhaust, or just anything to restrict the pipeing back to the stock size, maybe that would help as a temporary fix....

 

[Drewcool2]

You may be right about the computer using a closed loop fuel map when it's at WOT, im not sure. But should a CAI intake and exhaust/HF cat change it so much to the point where I have to worry about it running lean?
About the timing, maybe it’s the cam angle sensor...?
And, no unfortunately I don't have a silencer to temporarily fix it.
Thanks for the input though.