Logged data w/ Datamaster & I think I'm rich, or am I?

Lone Ranger · 02-10-2004, 08:06 PM

I can see there is a learning curve to encounter when looking at data collected and recorded by Datamaster. Recorded a file this afternoon, a whopper...2.8 megabyte file (about a 45 minute drive). My passenger side O2 sensor seems to have taken a little longer to get going than the driver side, it was stuck on 4 mv for a short time maybe a minute while the left one was doing the expected flipping high and low rich/lean dance, mainly this occurred during open loop.

My car, a '95 LT1, went into closed loop at 139.6 F (59.8 C) coolant temp. I don't have specs for LT1 on hand so I assume that is the proper temp for crossing into closed loop operation.

As for the data, well, my Lterm fuel trim seems to show rich but not all the time, but the numbers seem to favor the 119 - 121 range. Didn't see either side right or left diverge the numbers stayed together, i.e. 121 left 121 right.

Mainly, I just got to learn to interpet what I'm seeing. But in the fuel trim areas both short term and long term on average it shows red background (rich) more often than normal (white background) or lean (green). I do see lean (green) Sterm values when Lterm is rich (red) and to me that makes sense like the PCM is commanding lean operation because the condition is being read as rich in the Lterm.

Hope I have that right.

Help. :banghead:

Lone Ranger · 02-10-2004, 08:17 PM

If I made a shorter recording, take the car out while its at operating temp and drive for ten minutes or less, anyone know of anyone who has Datamaster and is not new/dumb about it like I am, who might be willing to recieve the file via email give it a glance on playback and let me know how it looks?

Just curious. :)

Lone Ranger · 02-10-2004, 08:20 PM

If one O2 sensor was lazy and the other not, wouldn't that cause the trims to be diverging (split), i.e. left and right trim numbers not close to each other?

[Modified by Lone Ranger, 6:21 PM 2/10/2004]

ZD1 · 02-16-2004, 05:16 PM

On the O2 Sensors you could always swap em to see what happens, of course a real corvette guy would just replace both an call it day.

You got to remember that the LT term covers a large portion of the spectrum vs the Short term which just that instant and RPM.

LOL