lots of knock at 10psi, everything looks ok....

[VadersV6]

I could be wrong, but this is what Ive always believed to be the case...
High oxygen content means you havent completely burned the mixture. The fuel hasnt been completely burned up, therefore, the oxygen used to burn it is still unused in in the exhaust stream. High oxygen content=rich=high o2's. Its in fact NOT rich, but the computer thinks its rich, so it pulls fuel.
Same would go with an EGT gauge. Exhaust leak cools the charge, brings the EGT's down and makes it look like a rich condition.

 

[Momar]

That is not quite right.

All an 02 does is detect oxygen. If the engine runs lean, there will be more air than can be used with the supplied fuel. This oxygen continues on into the exhaust. If the computer detects to much oxygen it can tell that it was lean because it was not all used up in combustion. If it If it was rich, there will be to little oxygen left in the exhaust.

If you have an exhaust leak, it lets extra air into the pipe, and will make the computer think that it was running lean, and add more fuel.

 

[SyHopeful]

Originally posted by 87gninpa
when i get up to about 10lbs of boost, my caspers knock guage goes all the way to red before i can even react. o2s are above 760 at WOT, all sensors are in range, fp is set at 44 static.....dont know what else to look for...any ideas? could this be internal? otherwise, engine runs very smoothly and idles perfectly

Mine does that too. I'm running 15psi, about 57psi of fuel pressure at WOT, all my #s are fine, but the knock gauge starts creeping up until my car shifts into 3rd. Then the knock completely disappears. I just replaced both motor mounts and my trans mount, recently got my driver's header welded up (crack in the usual place), and just can not for the life of me figure out where this knock is coming from.

 

[turbo2nr]

Check for loose stuff. Try race gas!. Do you guys run straps on your motors to keep them from flopping around? Does your TPS go over 4.5 volts at WOT, need to get fuel enrichment mode. Any funny other numbers on scan? BLM #s look normal at various loads on motor? 110-120 or so. Maybe fuel system has a problem? I once had an alternator go bad and it did not put out enough voltage at med-high boost. I got knock, rough ride. Could be many things, need more info.