I mainly tune off of Lambda and reverse it to EQ. I am not sure why I do it that way. Maybe toooooooooooo much time with Ford crap.Quote:
Originally Posted by DrkPhx
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I mainly tune off of Lambda and reverse it to EQ. I am not sure why I do it that way. Maybe toooooooooooo much time with Ford crap.Quote:
Originally Posted by DrkPhx
It has been a while, but I think the Tech II shows target AFR and % of E on flex fuel trucks.Quote:
Originally Posted by gmh308
You should have locked this thread after this post, Joe. :grin:Quote:
Originally Posted by joecar
Isn't EQ1 based on AFR? :laugh:
It seems to me the PCM generally does all of its work using EQR, and provides the AFR pid as a matter of courtesy/convenience/information.
If I lock this thread, then someone who may have some insight/revelation will not be able to post... :cheers:
If you really want me to lock it, I will... :gossip:
AFR is still important for determining injector pulsewidth.Quote:
Originally Posted by joecar
:hihi:Quote:
Originally Posted by joecar
It just seems like this thread is a mile long,
it has been informative tho. :blahblah:
Does anyone have a dbf for something like an 01 Vette and the later flex fuel trucks? Maybe even the dbf for the bin's I posted.
Joecar if I overstepped the boundaries delete this post.
I don't see any problem...
everyone has contributed their information/opinion in a civil manner... :cheers: ...thanks to all, this is a credit to EFILive forum members...:cheers:
discussion of differences is fine, everyone learns constructively...:rockon:
I think mr.prick (his real name) was simply joking about the thread being quite long...:hihi:...but that's ok.
I use both EQR and Lambda from my LC-1 (in serial/digital format)... I like EQR better than AFR, it lets me think easier in relative terms (relative to stoich).Quote:
Originally Posted by CalEditor
I don't know who would have those...Quote:
Originally Posted by CalEditor
The worse that could happen is a "no" response.
I don't see any boundaries being overstepped...
Oh, yes, I agree, that's how the PCM knows how to determine the actual fuelmass required.Quote:
Originally Posted by dc_justin
The PCM does applies the modifiers in terms of EQR, and then at the last moment applies the stoich AFR to arrive at commanded AFR, which is required for calculating fuelmass, which then determines injector pulsewidth.
:)
I still think a FF OS for F/Ybody is a good idea. :devil_2:
Hey guys, I posted this over at the tunercats forum monodax.com also.
I was under the impression that changing the values in the stoich AFRvs % alcohol in fuel table would make NO difference to my vehicle: 2005 4.8L Tahoe NON FLEX FUEL.
The table makes sense if you have an alcohol % sensor. Well I changed the values, up to 12.5% to 14.37 and EFI Live reports the desired AFR as 14.37 MY WOT also reports richer in EFI Live (14.37/1.165).
What I'm asking is why would EQ1=14.37 if I dont have a flex fuel vehicle?
EVERY pump here in Atlanta says may contain up to 10% ethanol so I'm assuming its in 90% of the pumps. Unfortunately this is my wifes truck so I dont have a bung for the WBO2. How much will my reading be skewed when the sensor is 6" in the tail pipe? What about taking out the rear 02 and installing there?
Well I hooked up the WB and have some results. Can someone point me in the right direction with the data I have?
I commanded open loop and reset fuel trims via EFI live scanner(love it!)
Commanding 14.68, at idle WB reads .98L 02's average .560's mv's
Commanding 14.37, at idle WB reads .96L 02's average .560's mv also.
I FINALLY understand (found) the closed loop airflow mode! NOW the rich/lean 02 volts table makes sense. My gut tells me to raise/richen the mv to .550 across the board. Also, it appears to me by changing the value in the % ethanol table, I'm telling the PCM that EQ1=14.37. Is this true?
Because you changed the value of AFR=EQ1 :)Quote:
Originally Posted by TunasTwins
All it does is put an AFR number to EQ.
Changing the Stoich AFR value will change other tables when viewed in AFR but
will not actually change the amount of fuel delivered.
This can be changed if you are using AFR instead of EQ/Lambda to tune and
your WBO2's is not able to change Stoich AFR=Lambda1 to match EQ1.
It's not necessary as long as EQ is properly set i.e. not lean during PE
FYI
If your WBO2 is not able to change the AFR value=Lambda1 then make a calc_pid.
6" from the end of the tailpipe is not a good place for a WBO2,
3' from the end is minimum.
IncorrectQuote:
Originally Posted by TunasTwins
Please explain. The vehicle is NON flex fuel. Did I effectively change the EQ? Will this change the target AFR in closed loop also? Is changing the 02 switch point mandatory? TIAQuote:
Originally Posted by CalEditor
Did you post a question on another forum?Quote:
Originally Posted by TunasTwins
I will try to explain, but I need to pull an earlier flex cal first
What's more to explain?
You changed the AFR value of EQ1, this changes all Commanded AFR values.
(Stoich AFR/Commanded EQ)=Commanded AFR.
I have been following this also.
I am wondering, don't the narrow bands only read stoich.
Can the computer compensate for the difference in commanded?
When I get a chance I will do some logging to see the difference but it seems that even if you command 14.37 that the narrowbands will still look for 14.63.
Or I may be way off base. Do the switchpoints make that difference in the stoich points?
Any insight?
Brad
The NBO2's look for Stoich regardless of what AFR stoich is.
How Wideband (and narrowband) Sensors Work
Correct You are changing Stoich switching AFRQuote:
Originally Posted by bmax
This is figured from Air Mass and Fuel Mass
Can some one post the cal file for 1GNEC13Z82J242956 maybe I can later
This is basically what I'm trying to verify, along with the function of the %alcohol fuel AFR table (I'm using tunercats) on non flex fuel vehicles. I did post over at monodax but it usually takes a while for an answer. TIAQuote:
Originally Posted by bmax
sorry, didnt see the above post from MR. Prick. Guess I'll leave the 14.3 in the % alcohol table and set the 02 to switch around .525 and see what happens. Thanks guys.
JWS6Quote:
Originally Posted by TunasTwins
pm me your email and I will get you more info.
The AFR table is simply a reference lookup for the ECM to determine fueling in relation to measured (MAF) or calculated (VE table) air mass flow.Quote:
Originally Posted by TunasTwins
i.e. in in open loop if MAF indicates 14.7 grams per sec of air and the AFR table at 0% alcohol is cal'd to 14.7 the injectors will delivery 1g/s of fuel.
If the table is set at 10:1 fueling will be 1.47 g/s.
It is a variable table to support flex fuel so that when the ECM knows via the fuel composition sensor or virtual fuel sensing system that the ethanol content for example is 50%, it can adjust the fuel flow accordingly to represent 11.8 parts of air to 1 of fuel by mass. In non flex fuel cals it simply sits at 0%. Pre flex fuel PCM's still had this calibration but it was a single number for gas.
NB O2 sensors are simply that: sensors. They measure and "report" oxygen content of the exhaust gas and are designed to be most responsive around stoich in terms of voltage output to oxygen content.
The ECM "drives" them by varying fueling around the crossover point/rich-lean threshold. There are 3 key points being the crossover point, the rich turn-around point and the lean turn-around point.
For example the crossover might be set at 500mv the lean turnaround 250mv and the rich turnaround 750mv. So the ECM adds fuel and the sensors see the voltage get to 750mv and then it pulls fuel until the sensors see 250mv and then it adds full again and graphed it looks similar to a sine wave. In an ideal world the crossover will represent stoich and the lean/rich turnaround points will be an equal distance from the crossover point but generally the calibrations will be adjusted slightly to cater for different O2 sensor response curves, engine characteristics and to achieve emissions targets, and maybe if thats all ok maybe some fuel savings can be fitted in as well by keeping them on the lean side a fraction longer than the rich side without screwing emissions.
:)
This is a 2002 5.3L Tahoe Flex Fuel calibration from a 512kb 0411 PCM in bin format
I tune my car in OLSD as I can do it quite well and car runs fine like that whenever I put any e10 in it i have noticed it run a bit lean. I mainly run the e10 just to keep the fuel system cleared of water, more of a maintainence thing really. I basically have 2 tunes setup for it so I can reflash it once the e10 is gone from the system.:)
The way I read it is we basically will use 5% more fuel running E10 over 98 ron fuel would that be a fair estimation?
If this is the case E10 needs to be more than 5% cheaper to attain any financial benefit from doing so. Given that E10 is usually only about 2-3 cpl cheaper than 91ron the average punter is getting ripped when they use E10.
cheers
Back from the dead... I just read this whole thing. My big question is...
On 91 my tune is really close, but I also run vp100 which has a stoich rating of something like 14.16. I've had 100 in my car for while and my LTFT are positive. I run CL MAF. I do tune in AFR(which I've been reading for years not to but I'm not changing lol).
I know what I want my AFR to be and it seems that is where it is. I set my car to run 12.3-12.5:1 on 91 which equals closer to 12.1-11.8:1 on 100 and that's where it runs.
So here is the big Q..
If I change B3601 to 14.16 what will I see happen? Will my fuel trims correct themselves closer to 0, when I scan WO2AFR(efilive) will it show me 12.5ish(even though my gauge will still show 12.1 unless I configure logworks) or will it do both?
And not that I have any plans in the near future to change over to e85(presumably exactly 85%), what would happen if I left everything the same and set B3601 to 9.85. Would it be in the ballpark?
Thanks
Kris
Not sure why your LT keep adding fuel unless youa re seeing more ethanol or just better air/temps. All things being equal, your LT should get close to "0" by themselves. Your ST and LT trims adjustments are basically tweaking fuel delivery to keep your afr at stoich.
If you change B3601 to 14.16, 14.16 becomes your stoich. EFILive will then make changes to your OLCF table and your PE tables reflecting changes to B3601.
Much is dependent on what your currently have B3601 currently set at using your 91 fuel. If your B3601 is set to say, 14.63 and your change B3601 to 14.16, your PE table will change as well. I will assume your current B3601 is 14.63 and your PE table is flatlined at 12.3. If you change B3601 to 14.16, your PE table will be revised to approx 11.7:1 from 12.3:1. 11.7:1 is rich for even e10.
Try it. Create a dummy tune file of a current file. Change B3601 to 14.16. Save it. Open file back up and look at look at PE table. You will have new values.
My suggestion, find out what ethanol content is in your area. I bought a test kit used by airplane owners. I get mine from EAA in Oshkosh, WI. In SE WI, our E10 is really E5 for the summer blend.
Not sure about all WB's as far as readings. I believe Innovative LC1/etc c an be programmed to reflect revised stoich.
As far as E85, your could adjust B3601 to reflect stoich for E85 9.85. You would be in the ballpark. Question would be, are injectors and fuel system able to meet demand?
We have e10 oct 31 til jan 31??? here. It's considerably less during the other months. So my fuel trims being positive have nothing to do with running a fuel that commands more fuel to reach stoichiometry?
As far as air temps go, I live in the high desert. It can be 90 or snowing on the same day.
Your LTFT should get back to close to "0" all things being equal. The problem is what could cause the engine to want to add fuel. Cooler temps, lower humidity, slightly different blends of ethanol, whatever. Have you tried resetting LTFT and see what happens?
If you were to start out in the morning with cool temps and a nice dense air charge, I could see the 02's commanding more fuel. If you continued driving and the temps went from say 30* to 90* and humidity jumped, your 02's would normally start pulling fuel to lean car out to maintain stoich. There are a number of influences to ltft adjustments than just fuel type.
As far as fuels, e10 will cause your 02s to add fuel to return car to stoich of 14.63 or whatever your B3601 is set at. Over time, your LTFTs will make adjustments to work with the e10 up to a point. While e10 will cause your 02's to command more fuel for a period of time, it should balance out eventually. They will never be "0" though.
Try this, assuming B3601 is currently B3601, change this tables to 14.10, load the file to your ecm. Start up scantool and log stft and ltft. Chances are very good, stft/ltft will pull fuel.
lastly, just because your pumps show e10 stickers, the actual fuel may in fact , be considerable less than 10% ethanol.
Ok so I reset my fuel trims and immediately they went positive and stayed there. Do you presume I just need to retune the car?
On the flip side I set b3601 to 14.17 and my commanded matched my actual afr idle average and in pe. I guess that's good lol. I need to tune my car at sea level I think because I'm sure if they are positive here at 4500ft they'll be way positive there which probably isn't a good thing. Unless I'm thinking backwards and positive fuel trim is pulling fuel not adding it.
Have you changed intake systems or had your intake apart? You may have a persistent air leak. ?Can't believe a tune would help..
Any mods? Can you attach a log from scantool showing stft and ltft? Include a copy of the tune as well.
Positive trims mean fuel being added. FWIW, Not sure how big a positive reading you are getting but a couple of percentage points isn't a big deal.
.
I'll post my tune and log when I get home. I just logged a 10 min drive to my friends house. Seems to be about +10. I don't think there is a vacuum leak the maf is reading 10gs/sec which it has always seen at idle. I think my fuel trims may have always be positive though.
But here is what it is right now. I just added a few degrees of timing to see if I could pick some hp on the butt dyno. First log is driving to a friends house the other one was a quick little blip to check my afrs. I'm not real happy with the tune on this car anyways so I'm going to redo it. I think I may know why my fuel trims are off.
This car is a 98 trans am(98 pcm) m6 forged 347 ls6, 228/232 112 11-11.5:1 cr 100 octane pump gas.
Quick solution: With a cam in that range, your 02's will pretty much think the car is always lean due to 02 sensors seeing unburnt fuel. That is the reason you are seeing positive fuel trims. I would guess that the car acts and reads quite lean at idle.
I ran a 224/228 on a 114 and had same issue.
After a quick look:
MAF table is rough. MAF table is normally a smooth transition from low to high.
VE Tables: Again, really rough with spikes. I would expect a more rounded graph in the 4800 rpm range. Also seems like lower rpm, idle range is very lean.
IFR table: Not sure what injectors you are running but the IFR table values have almost doubled over stock.
What type of injectors are you using?
What intake manifold are you using, LS1, LS6, FAST?
Stock TB?
Spark tables: Changes made to date are pretty much ineffective.
I ran a very similar setup with 11.5:1 CR.
Crazy elevation (7200-0ft) and weather changes. I'm keeping the o2 sensors, I need all the correction I can get lol
I posted some information that wasn't so good.
Set you stoich to 14.0 if you have E10
I would think if you have E10 then you will be on the High Octane Table
http://i1106.photobucket.com/albums/...4%20E85/33.jpg
http://i1106.photobucket.com/albums/...HighOctane.jpg
http://i1106.photobucket.com/albums/...5/E85Adder.jpg
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