Black01M6SS

iTrader: (3)

So I keep reading threads where people are talking about part throttle/idle tunning and every time someone mentions the air fuel ratio being higher than around 13:1 people start saying that is LEAN. Am I wrong or are these people mistaking what you want at WOT for what you want at idle/part throttle? I know 13:1 at WOT would be a bit lean but at idle that is rich...right?

Correct me if I am wrong but the stock narrow band o2's only know where 14.6 is and will read a higher/lower voltage if the AFR goes above or below 14.6. The factory PCM targets 14.6 but will over compensate in closed loop causing the mixture to go slightly richer and slightly leaner than 14.6. That means that whenever the car is in closed loop and not in Power Enrichment mode the car will be running closed to 14.6 if it is tunned correctly...right

I'm trying to do AutoVE tunning with EFILive. My Commanded AFR is 14.63 and after logging ~100miles of data my actual AFR is matching up fairly close to what is being commanded. Meaning I'm anywhere from 14:1 to 15:1 at idle/cruse. That is good right? I'm asking because so far I haven't been over ~35% throttle. I need to populate the higher map/rpm cells but I'm afraid to load it up with it running around 14.6:1 AFR. I know if I get into the throttle hard enough it should go into PE mode but I'm afraid to just put the hammer down and hope it goes into PE mode and richens up enough.

2002_Z28_Six_Speed

iTrader: (19)

It depends on what your goals are. If you want an emissions street car than 14.6 is a good number to drive for under low load. Where you would want to fatten it up and where you are under load. The VE table would also have a calculation for unity meaning AFR, IAT, ECT, ect are all the same. But yes, the PE will force the AFR to safe values under throttle pressure. With the AUTOVE you are supposed to tune out PE and modify the tables to provide a more flat AFR acrost the board. There is more to good tuning than what is stated in the AUTO VE.

If you also filter out data for varying ECT, IAT, and low inj PW you will have closer values. Ever click to see the max and mins in each cell?

If you have a non emissions car then the magic number 14.6 is completely meanless. There is no use to strive for that number. Give the car what it likes. Possibilty richer than at at rich [assuming the measurement was accurate].

macca_779

Your doing an AUTO VE so I'll assume your doing it with a WB O2 sensor. If you are using a WB it wont matter that you hit PE. Remember than Ben's are generated comparing commanded to actual. It doesn't matter what commanded is. When I do AUTO VE tuning I simply turn off DFCO and command all my 14.63 cells (CL) to 14.5. Everything else I leave the same, including my lean 16.3 cruising AFR's.

gametech

iTrader: (1)

Your basic assumptions thus far seem correct.

Black01M6SS

iTrader: (3)

This is not an emissions legal car. At first I was afraid to drive the car with it running "lean" at 14-15:1 but then I realized that almost all cars run in that range from the factory at light load. I've been afraid to do any AutoVE logging at anything other than light load though.

So what I'm getting from this is that I want to do away with PE mode while doing AutoVE. I should set my commanded AFR to something that would be safe at WOT and start logging runs progressively getting closer to WOT. So I would make a run up threw the RPM range at say 25% throttle and view the log to make sure it didn't go lean. Then up the throttle a little bit each time untill I can go WOT without it going lean. At that point I'll be able to make enough WOT runs populate the entire AutoVE table.

So could I just set my Commanded AFR to 12.5:1 and set my PE Mode AFR to the same 12.5:1 then do AutoVE tunning working my way up to WOT? I'm running the engine NA right now. I want to make sure I know what I'm doing before I strap the F1A on. I did look at the min/max values earlier today and If you wouldn't mind could you PM me on what filter settings to use? Right now I'm just using the ones from the tutorial that comes with the software.

Black01M6SS

iTrader: (3)

Yes, I'm using an LM1 wideband. That is what I was thinking but I would sure feel better about things if it was running a little richer. I've loaded it up about as much as I dare "around 35% throttle up to 5500rpm" and it has never commanded anything other than 14.63. 16.3:1 lean cruse eh? Makes me feel better about seeing mine go to 15:1 at times.

Good to know. I thought I was going crazy for a bit. I've read many post where people were saying you shouldn't go over ~13:1 AFR. I think some of these people were just stating what they had read in other post...and what they had read was reguarding WOT AFR not idle/cruse. Confusing to someone trying to learn.

2002_Z28_Six_Speed

iTrader: (19)

Basically, it would not be damaging to flatten your commanded AFR table to a certain value if that is what you are asking. I mean you have no cats, right? Just make sure the car is running good like that and that combusion is ensured. Throw out any data that makes the curve look impossible.


As for how lean can you go? Sure 17 against 1 at light crusing is not unobtainable. Just dont start there!

Black01M6SS

iTrader: (3)

Right, no cats. I think I will just set commanded to like 12:1. It seems like it would be easier to concentrate on one safe number.

Haans249

iTrader: (24)

If I were you, I would leave it like you have it right now with 14.63 at cruises. Remember, you can set the PCM to command any AFR you want and at what rpm and MAP. So, if at 40% throttle (which will give you a general MAP reading) , you can start commanding a richer AFR and if your VE table is spot on, it will put the fuel to get you to that commanded AFR. So, you pretty much don't have to worry about PE at the moment, and like everyone else said, you have to filter out extraneous data like low ECT's, large swings in IAT's, DFCO etc... As far as 16+:1 AFR at cruise goes, thats pushing the limits there, and I would personally NEVER put my engine cruising that lean. On the same token, cruising at 12:1 is also far too rich to be cruising around on. If you have any questions feel free to shoot me a PM.

Good luck!
Adrian

DaveX

Just do a manual % increase for the cells in the VE table where you are concerned about going lean and go from there. As long as your watching your WB you will be fine. Start rich and lean it out. Change your oil when our done...

macca_779

Pushing the limits you say. Really I'd like to know what you base that information on. I run my car at 16.3:1 below 50kpa. Here are the lean cruise settings of a stock VX SS commodore (lean cruise used to be legal and active in Australia remember). I've never heard of anyone having problems running like this, and if GM can do it going as lean as 17.8:1 why can't we go to 16.



This is a conversion for an EQ modifer to AFR to make it easier to see the data.

cantdrv65

iTrader: (3)

Just watch your wideband when running the high rpm and loads in autove.

Haans249

iTrader: (24)

That is on a stock cammed motor, which has very even and friendly valve events and makes it possible to run a motor that lean at cruise. Try that on a nicely cammed motor and say hello to some misfires (possibly serious), stalling coming to idle, and possibly terrible driveability. Just because GM does something does not mean its the end all for ALL applications. Of course that goes for me as well that 14.63 won't work in ALL applications and can very to some degree, but it works in most, and its a good base to start at especially if he is VERY worried about running the motor lean. Look at his setup....F1A....I don't think he will EVER want to see anything close to 16+:1 AFR's on a setup like that no matter what load and rpm we're talking about.

Best,
Adrian

2002_Z28_Six_Speed

iTrader: (19)

Hi Adrian. Just for more useless knowledge. I have a 5,3 with a Z06 cam. I am sure the cam appears larger due to small displacement.

I have done lean cruises as far as 17:1. The car was pulling 43kPa vac sig. It has worked on my lower compression motor without error so far. Also the Z06 cam isn't that radical with ramp rates and such.

Anyways, I feel you could be right. And of course, I haven't tested my car as GM would have. Overheating, overweight, bad fuel, ect...

I couldn't comment on how it would work with a high comp radical cam or blower set up. Just interesting stuff to know.

Haans249

iTrader: (24)

Oh, I agree completely, there are some setups that will easily be able to support cruises like that. In this situation, it would not be a good idea, and would be pushing the limits. The Z06 cam is not a large cam in any CI, so that is most likely why its working out well in your case. But, in this case, I believe sticking with 14.63 as a base is advisable, and if he feels like trying something more lean, then go for it, and see how it works.

Best,
Adrian

Black01M6SS

iTrader: (3)

Ok guys, I just spent the last couple hours confusing myself some more.

I've done around 150 miles worth of AutoVE without ever getting into PE mode. I've stayed below 35% throttle untill today. I wanted to hit those higher map/rpm cells today and I wanted to do it safely so I set B3601 "Ratio of Air to Fuel for Stoichiometry" to 12.5. Now since my commanded and actual have been matching up pretty close in the area's where I have done AutoVE I expected to see my AFR now around 12.5 as long as I didn't stray outside of the area that I had done the AutoVE process.

So I did a reflash and fired it up. Commanded was now at 12.5 but my actual was still around 14.6 and when I started logging the AutoVE Ben was around 1.15-1.21. This is what confused me. Maybe I have it all wrong but I thought since my VE table was pretty close in this area before it would still be close to the AFR that I was commanding. If commanded=actual at 14.6 why doesn't it still match up when I command 12.5? Anyway this confused me so I pulled over and reflashed with my previous tune. I went back to logging and with a commanded 14.63 my AutoVE Bens were back around 0.99-1.01.

So I finally decided I would just go for it and see what the AFR was when it went into PE mode. So I clear everything out and get ready to log a "hard" run. When I hit the throttle my AFR drops down into the 11.8-13.2 range. It took around 65% throttle for my Commanded AFR to drop below 14.63 and when it did change it only went to 14.58. The commanded jumped around a few times commanding different things but I think the lowest it ever commanded was 14.37. The car was running much richer than that because my VE table is still off. The thing that worries me is that as I keep doing the AutoVE process my actual should equal my commanded and my commanded is to high in what I'm guessing is PE mode.

2002_Z28_Six_Speed

iTrader: (19)

Can you label and post the before and after tunes and logs?

Also, just to check what filters did you apply to the logs?

Black01M6SS

iTrader: (3)

This is what I started with. This is the tune I was using when I blew up my stock shortblock with 11psi. Black01SSM6rutan[1]_0001.tun

This is the tune that I'm currently working with. 402_PE3500.tun

This is a recent AutoVE session from the above tune. 402VE5.efi

This is the tune where I tried to do away with PE mode and I thought I had it set for a strait 12.5 AFR. The car was still running around 14.6 AFR with this tune. "12.5 was commanded" Sorry, I didn't save the log. I didn't even drive far with it like this because I didn't understand what was going on. I just went back to the tune I had before which is the one I'm currently working with above. 402noPE.tun


Let me know if you would like me to log anything specific. The filters I'm using are the ones they tell you to setup in the AutoVE tunning tutorial. I'm pretty clueless when it comes to all of this.

2002_Z28_Six_Speed

iTrader: (19)

Ok. One thing want to do is leave the B3601 stock; 14.63 or whatever.
Mod your B3606 and B3607 to where it can't sway from that value you want.
Then go in and flatten your B3605 to whatever value you want. Say .87 eq ratio or 12.8 AFR.

If you can find out what temps your ECT and IAT are going to stay around by driving down the highway you might log those and then program filters to filter out anything too far away from that.

Make a filter to reject too low of a battery voltage just in case.
Make a filter to reject and frames with KR.
Make one to reject injector pulse width of less than 4ms.

I just see some large peaks on the 402noPE.tun so maybe some data is getting aplied that is not reliable and will need to be filtered.

Are you reading your AFR in EQ or real AFR in Tune Tool?

Haans249

iTrader: (24)

So I just went through your tune file that you're currently running. There was one BIG issue. You were commanding 16+ at WOT in the commanded fuel vs Map table. That is probably why you were still seeing 14+ AFR's. Also, your PE is completely disabled, so it was never a problem to begin with. You must understand that when you're in a Open Loop Speed Density tune the PCM commands the fuel from the B3605 table, and it uses the VE table to decide how much fuel to put in. Here is your corrected tune, try this and see how your WOT runs are. Check out the difference in the tunes by comparing the two tunes together.