Running TTS datamaster-

1. My left o2 (new) readings go from 100mv to 980mv whereas my right o2 only ranges from like 450-965mv- do I have a bad o2 there? No PCM codes thrown.

2. Map reading is like 87 at WOT, is that okay?

3. Fully warmed up- the car will always run in closed loop. If I have been idling for over a minute it goes to open loop then the second I press the throttle it goes back to closed loop, even WOT.

4. On WOT- spark advance ranging around 36-40*, at 4200rpms the torque curves takes a drastic dip til 5000rpm, and spark retard is from 1-5* with knock counts increasing. Should I pull timing or add fuel in that zone?

Thanks,
James

 

How do the left and right long term fuel corrections (BLM's) compare for the various fuel correction cells? With the difference in range on the left and right O2 sensors, there should be a difference in the BLM's.

MAP reading at WOT has to be compared to the barometer reading. Its the difference between those two that shows how much you are losing in the intake tract. The higher your elevation, the lower the barometer. The "flag" for closed loop means the closed loop is "enabled". When you go WOT, closed loop stays "enabled", but the flag for "PE mode" and "learning enabled" will change, indicating its in PE mode, and ignoring the O2 sensor feedback. You have to setup the field in the upper right hand corner of the display to indicate the flag settings as "0" or "1".

If its dropping out of closed loop at idle, the O2 sensors might not be staying hot enough - unusual on a 94, because of the 4-wire heated sensors.

I wouldn't touch the tune until you figure out if you have something wrong with the fuel control on the right side. You should also try and identify the source of the knock retard, before you start fiddling with things.

 

Ok, so I'm looking at the data right now (and getting a better feeling of how this works), and the Lterm variance for left is -2.3, right -7.8 on average. The right o2 looks "lazy" and when the car is idling the "right O2 rdy" function deactivates after 30 seconds. The "closed loop" function goes to 0. The second I touch the throttle- goes back into closed loop 1, and R o2 rdy 1.

What AFR is 400mv, because that's where the right o2 hangs at idle- no variance. At WOT both o2 sensors give similar readings. Also, at WOT closed loop switch is 1.

Thanks,
James

 

You got to fix the O2 before wasting time on anything else. If one is bad I'd replace both of them. O2 should not drop out of ready after you enter closed loop unless it or the heater circuit is bad. You could swap left and right if you want to prove it's the O2.

 

I'm dead positive the right o2 is lazy/needs replaced. The PCM threw a code for the left one a month ago, so that one is a brand new ac delco unit. Without the datalogger I never would have known, and probably would have been blaming my new opti for my idle miss. I bet I know why its bad too...

1. The origional o2 with 111k miles
or
2. I had soldered in extended wiring when installing the longtubes. I bet that may have jacked with the resistance just enough to make it go bad?

 

If it's a cable splice problem then it will not move to other side if you swap o2's left to right. Also soldering wires should not add any/or enough significant resistance to effect the O2 unless you have a cold solder joint. If cable is bad then I suggest re soldering the leads. To verify heater circuit on cold engine, pull the O2's, then w/ key on engine off verify the heaters are working, O2 should get hot from heater, don't burn yourself.