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Scratching my head at this one.

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Old Feb 22, 2011 | 04:45 PM
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From: Carrollton TX
Default Scratching my head at this one.

It would appear I have an O2 sensor thats slow to respond, or something is going on..

This started after we had extreme cold here in North Texas. or at least its when I noticed my STFT and LTFT from each bank are off a decent ammount.

No codes, no drivability issues, nothing out of the ordinary going on.

I've attached a small datalog.
 
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Old Feb 23, 2011 | 03:38 AM
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RPM is probably needed.

You don't need to record ECT if the engine's warmed up, but post its value. IAT, too.

If VSS (speed) isn't 0, record it too. But 0 will do fine.

In case you weren't connected over CAN and are able to, please use that. You'll get more readings per second and thus less jitter.
 
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Old Feb 23, 2011 | 06:59 AM
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I was over can. I can log it this morning. While driving it seems like I have a lazy sensor.

I might have to rip out all 4 Bosch sensors and go back to ngks.

So what sensors should I like to repost?

Stft, ltft, vss, ect, o2 high res b1s1,o2 hr b1s2. Rpm
 
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Old Feb 27, 2011 | 10:01 AM
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Sorry, missed your reply!

The basic idea is that trims etc are not much use if you don't know rpm (and vss if it's not zero).
Values when warmed up would be best at least for now, so just the value of ECT once. Each reading you add slows all the others down. Similarly IAT once.

So, rpm, maf, stft1 & stft2, ltft1 & ltft2, map.

Two periods of readings, maybe a minute each, at idle and again at a fast idle (about 2500rpm).

I'm not sure about the O2s but probably all 4 of them. But, if you like just graph them and see what they're doing. The two banks should be very similar.
The downstreams (binary type) should either sit at a voltage or wiggle a bit but not much, s-l-o-w-l-y between good low values (0.2V or so) and good high volts (0.8V or so). The upstreams are the AFR (linear) type so any time you press or blip the throttle they should change volts to a new position instantly. (The downstreams should be utterly different to the upstreams.) But add them in to the data by all means.
 
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