Solders18

hey everyone, i am trying to tune my 87 350 tpi for better mileage. i am working with the ARAP bin and adjusting stuff as needed. so far i have brought back the timing tables to something reasonable, and long crank fix. i am working right now on getting my BLM's right about 128 +/- about 4. I have most of the range within 2 right now and am readjusting for a new oxygen sensor. my problem is this new oxygen sensor reads everywhere. at idle, it will be just jumping from 0.150 to 0.750, it never stays at any given rough value for more than maybe a second or two. i have gotten my BLM's at idle to be 128 fairly consistently, but the oxygen is going crazy. is this normal or did i get a bad sensor? thanks for any input.

Solders18

Heres a graph of O2 and engine speed

xch3no2

That sounds like the normal swing of an NBo2, it is called a cross-count.

Crosscounts are instigated and controlled by proportional gains and o2 volt limits.

Solders18

how come it is so drastic though? i understand that it is leaning out or richening but that seems like a big swing

utilityguy2

iTrader: (1)

seems normal. every time a cylinder fires it changes levels. ECM averages them I believe.

Solders18

so its a perfectly good o2? the one that came out was alot smoother, granted it could have just been toast as it was most likely the original O2. thanks guys for your help!