lean tune

[southern]

I have been tryin to get rid of my lean problem. I tried auto ve but got the same bens two or three times and still not running richer. So can yall look at my tune and log and see what yall think cause I am stumped.


2004 GMC ECSB Z-71 AEM Longtubes Modified with 3" Magnaflow, Intake, EFI Live, PLX Wideband, 206/212-.515/.522 112, stock heads milled .030", Patriot gold dual springs, comp pushrods, E-Fans

[swingtan]

Well..... For starters I'd disable Closed Loop mode. Your LTFT's are pulling 9% so I'm guessing you are trying to add fuel, but the O2's are pulling back out. The difference you are seeing in the commanded vs measured AFR's are probably due to a ground offset in the PLX. Are you running the Analogue connection from the PLX or has it had the serial connection mod? Running a serial connection will eliminate the ground offset.

Simon.

[Gregs]

you can't accurately tune the ve table unless you are in ol with the maf failed. read the tutorial on doing autoVE and follow the steps to modify your tune. the computer takes a combination of the maf sensor and the ve table so you have to fail the maf sensor and you need to force the engine to run in ol with o2 sensors disabled

look over this tune and compare it to the one you provided

[southern]

That is not a ve tune just a tune with the ve table from my ve tune. set up in ve tuning the wb still gad the same bens after to logs and retunes. as for the wideband i am just using the orange plug that cam with it. i have not heard about any other way to hook it up. but like i said in ve mode it kept reading lean.

[Gregs]

The tune I posted is what you need to run, do a log, apply bens...and so on and so forth. if your bens aren't changing anything after you've made a new tune then i'm thinking something must be wrong with the wideband setup somewhere, but i'm sure someone who knows more that i do will step in here soon.

[WeathermanShawn]

Are you sure you do not have 'Lean Cruise' Enabled?

[southern]

all lean cruise tables should be zeroed and disabled. unless you have to do a full flash to disable it. can anyone shed some more light on the wideband upgrade? thanks come to think of it it requires a full flash to activate so it should take a full slash to disable it right?

[southern]

i take it the wb mod is for v2 only i am still using v1.

[Gregs]

i did a full flash to enable lean cruise a while back. to disable it all i did was zero out the tables

[swingtan]

i take it the wb mod is for v2 only i am still using v1.

Correct. Serial WB logging is only available with the V2.


Are you sure you do not have 'Lean Cruise' Enabled?

Looking at the commanded AFR would indicate that Lean Cruise is not enabled.

I'll stick to the CL issue at the moment. You can not adjust the VE table using a WB BEN if you are still in CL. To make matters worse, you seem to also be using the MAF still, so any adjustments to the VE will make very little difference anyway, as the MAF takes precedence.

Simon

[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.

[swingtan]

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...?

Exactly what I was looking at. They seem to work OK for a while, but then stop switching. At this point, they indicate they are stuck in a "lean" state (very low OP voltage), but the LTFT's remain around -10% and keep pulling fuel. So either the LTFT learn rate is very slow, or the PCM has dropped into OL mode and turned off LTFT learning. If it was just a vacuum leak, the trims would keep things in check and the LTFT's would be positive to compensate for air flow not measured by the MAF. It should also be worse at low MAP readings, where a leak would have more of an effect. Maybe it's full PCM reset time and clear all trims, start from scratch?

Simon.

[southern]

when in pe wb says around 13 and is pretty steady. jusr looked over that log and yea nb shut down most of the log.

[southern]

may do that just a full reflash on a earlier tune or a stock tune and go from there

[Chuck L.]

Ne value???
http://omgili.com/o2-sensor-test-wideband

Scroll down to the "good info" video and clik on it....

[joecar]

+1 test your wideband sensor like in that video.

[southern]

Well still not sure what it is or was but setup a ve tune which I will include that has a lower ve the my other tune and did a full reflash along with running a ground straight to the battery with nothing else besides my wb hooked into it. Log shows it running rich everywhere and my wb is more stable and does not jump around as much. Still not sure about the 02's tho. Here is the tune and log.

[swingtan]

It might be time to upgrade to COS3. If you chart your WB reading at idle against your IAT's, you can see that as the IAT rises, the mixture is leaning out.This is easier to correct with COS3, but you can do it in the current OS using B4901 and B4901 ( it's a bit harder though ).

As for the rest of the log, where IAT's are fairly stable, the average BEN factor is between 0 and 0.95 which is fairly good. The log is quite short and misses many cells in the BEN MAP though,as well as the throttle moving around a lot. For a quick view though, it's headed in the right direction. The MAF is failed in the tune, but still connected so we can cross reference the VE table to the MAF. It shows that the MAF is set fairly close to the VE table in this tune, so the overall fueling should be fairly good once the O2's are switched back on.

I'd re-enable the O2's ( leave the MAF off for the moment ) and see how it goes. If the trims goway out again, then it points to the O2's playing up in some way. If it goes OK, then I'd re-enable the MAF and see what happens then.

Simon.

[southern]

Lookin at the 02's in the log they still look like they are messing up. Like I said tho the are fairly new. I should be able to run with out them tho correct? Would it be all that safe without them? I am going to get a good log or two tomorrow and see how far it is out in more cells before turning 02's back on. Thanks for the help

[swingtan]

Running full OL is fine..... IF you can trust the WB and have the fueling set up correctly.

[southern]

Well all is well ve is around .99-1.01 so wb is back up and working correctly. How much of a pain is it to swap to cos3 I was taking a look at it and it looks like the fueling table would be nice. And I am going to just stay running without the 02's truck is running great without them anyways. Thanks again for the help guys

[swingtan]

RE: COS3.... It's less of a pain going to COS3 than persevering with the stock OS ;).

[southern]

Well swapped over to COS3 and everything is smooth. Here is the first log and tune.90449045

[swingtan]

Looking much better!

[southern]

and a whole lot smoother and crisp driving

[bmax]

Southern,

Take a look at your commanded values in B3618.

They appear to be higher (richer EQ,) than what you have in your B3647 table. Remember the richer of the two values will be what The PCM will command.

Good luck

Brad

[southern]

pe still activates like normal and i am at 100 kpa by 50% throttle but it is working good so far just my shifts are softer now any thoughts

[joecar]

If shifts are softer, make sure your VE table is correct.

Then after that:
- reduce D0801,2;
- I see that D1108,09,10 are zero, but try setting them to 0.2s.

I take it the fluid level has been checked and is at least to the hot mark.

And, regardless of anything, set D0960,1,2 to all 100% to avoid conflicts with the PT up/down shift tables.

[southern]

thanks joe I will give that a try and see how it goes. Ve is dial in within +-.02 so no reason for that to throw it off. torque shows to be around 380 at wot.

[joecar]

Does 380 seem right for your motor...?

Then do the other things:


Then after that:
- reduce D0801,2;
- I see that D1108,09,10 are zero, but try setting them to 0.2s.

D0801,2 should have some effect.

[southern]

sounds low at the crank since what 325 is stock