New logs with '95 knock sensor installed...things look closer to normal now...except the left O2 is still dead...

I guess its switching between open and closed loop mode pretty frequently at idle. I've been watching the Closed Loop status bit in FreeScan.

Here's the CSV file itself straight from FreeScan (opens in Excel):
http://live4speed.com/highway.csv

Here's a pic of a chart featuring Knock Retard vs. RPM:
http://live4speed.com/kr_chart.jpg

And a pic of a chart featuring O2 mV vs. RPM:
http://live4speed.com/o2_chart.jpg

I chose a range of data including WOT and a couple shifts. It appears to me that the knock is showing up when I lift from WOT. I have Hooker LTs and SLP Loudmouth and its pretty damn loud, including when I let off...you'd have to hear it.

FYI I have installed a '95 Z28 M6 PCM and '95 Z28 knock sensor and have only used TunerCat to remove EGR, AIR, CAGS, lower fan temps, recalibrate for tire sizes and bumped idle up 25rpm.

 

you show an LT4 KM in your sig.
Have you tried that in place of the '95 KM.
I looked over you log files and all I can say is I wish mine was that clean....

I'll take a little harder look at the csv file and see if I can find anything.

 

LT4 KM was in the '96 PCM. The current ('95) PCM has the stock knock module. I'm going to hit it with an N2O wet kit so I'm trying to get rid of all 'real' knock or false knock retard.

thanks man

 

Have you checked for any exhaust leaks.
That would lean out the mix.
I would assume it would have to be a pretty big one to make that much of an effect.

You are definately lean on the L side but you already knew that.
Try switching O2 sensors to see if it is the sensor.
If the sensor sees the same thing I would say you have an exhaust leak.

 

The left O2 is dead - we hit it with a 2x4 and a 15lb hammer to get it out of the stock exhaust manifolds during the header install in August The only exhaust leak there could be is at the heads, and I've checked all that and everything is good. The O2 sensors are in the collectors and the next break is at the end of the collector so no chance of a leak there causing trouble. Waiting to hear back from Jason Cromer on O2 prices - local dealership wants $58/ea!

 

I'd say its safe to say that its dead then.....

Once you get a new O2 installed you'll be able to make a better test run and get more accurate data.

 

Knock when you lift is common before you shift... Injuneer's scanmaster write up talks about it (I thin its Fred's anyways) in more detail but its quite common for it to occur.

I get it, but the thing for me that keeps me happy is that I can stay on the gas (WOT) aftewards, and watch it go back down... So in my mind i'm thinking it can't be bad/real if its going away while i'm still on the gas. (I've been wrong before however, but i'm hoping i'm not in the whole knock knock case, heheh)

Jeff

 

Thanks Jeff, I just looked up Fred's ScanMaster article. Now my head aches. But I understand more than I did 30 minutes ago so that says something. Good to know that 10.3 degree spike between shifts isnt from a rod trying to reach the outer orbit of my oil pan I know I cant really 'tune' until I replace the left O2 so until then I'll settle for troubleshooting.

Thanks guys