lean tune

[southern]

That is just a normal tune NOT my ve tune. i will try to post up the ve tune when i get home tonight. but like i said that is my normal tune ot my ve setup. i know you have to set it up to tune the ve this is the third truck i have had and tuned just stumped as to why my a/f is not fallin in line like it should.

[swingtan]

Going back to the log file alone, the LTFT's seem to inversely follow the WB reading once some averaging is done. In particular, look at frames 7219 to 7683 and notice how the WB reading changes at the same time the LTFT's do. This to me says the VE table / MAF air flow is wrong and the PCM is learning bad trim data. This could be due to the PLX reading incorrectly lean, resulting in BEN factors increasing the indicated air flow ( by artificially increasing the VE / MAF tables ). These "falsely high" settings for the airflow result in a richer than commanded AFR, even though the PLZ may now say the mixtures are correct. When you turn on CL mode again, the NB O2's will try and correct the rich mixtures, pulling the AFR's back to where they should be and learning the data for the LTFT's.

If you can get hold of a different WB unit, or test yours in a known environment, it might shed some light on the situation. If I was a betting man, I'd be putting money on the WB reading lean.

Simon.

[southern]

kinda what I was thinkin or a vacuum leak somewhere. I am going to run a new power and ground this weekend to the wb and make sure they are directly to the battery and on a line of there own. I have the filter at the orange connector of the wb but is there any other way I can try to cut out any trash in the signal? Thanks for all the help tho guys. will post back when I have it wired back up or at least check the wiring on it.

[joecar]

...
I have the filter at the orange connector of the wb but is there any other way I can try to cut out any trash in the signal?
...

Which filter...?

[joecar]

Sanity check: during CL thewideband AFR should be oscillating tightly around stoich...

if not, then either the wideband is wrong and/or the narrowbands are wrong;

check the narrowband voltages during CL, take some logs.

[southern]

thanks joe

here is a log with nb voltage not use to lookin at them but they appear to move around like they should.

this is he filter I was talking about

*If you plan to integrate the SM-AFR with stand alone engine management systems, piggy back systems, data loggers or any other devices that utilize the two analog outputs, noise filtering capacitors must be installed near the application. The included capacitors filter out unwanted electrical noise produced from your vehicle’s ignition and other onboard systems. This provides added signal integrity for more accurate, reliable, and consistent measurements. Any 0.1uF 50V ceramic capacitor will work

[swingtan]

The 0.1uF cap is there to help stop high frequency oscillations from occurring in the PLX -> V1 interface. It's a fairly standard technique when hooking up analogue systems.

Looking at your log, it seems the NB O2's are shutting down after frame 1330. I can't tell if it's an issue with the O2's or if the tune is dropping in to OL mode, but it seems pretty strange. What does the WB signal look like if you run full OL?

Simon.

[joecar]

Ah, I looked at some PLX document, I see now, thanks.

[joecar]

To left of cursor: NBO's are switching at 1+ second intervals, too slow.
To right of cursor: NBO's are not working.

How many miles on the NBO's...?

[southern]

Nb o2s are a year old at most 12k on them.