$ee lt1 tuning cruise and idle

[steveo]

nah. and even when doing this, don't set the entire table, just @ operating temperature (44 degrees +), making sure you reject any data under that temperature.

[zoomo]

ok, i switched it to that.

not sure if you caught my edit,
just to make sure i understand perfectly, i will drive it like this (pe disabled, closed loop disabled and open loop afr set to 13.5) and then tune the maf accordingly to get the afr correct on the wideband throughout the rpm range?

[steveo]

that's the idea. you'll see 14:1 at 100 afgs and add 3-4% fuel to that range.

it doesn't have to be 13.5:1 specifically, i just figured that made sense since you can be a good amount rich or lean and not hurt anything. once it runs at roughly 13.5:1 all the time, you're good to go.

you're going to probably fix up the maf table then flash it, and do it again and again until it's just right.. then maybe go into speed density and do a few runs over your VE table too.

remember this will not work well if your wideband isn't right on. if you start getting results in lower airflows that are quite far off from the progress you've already made at trying to get your BLMs close with the narrowband, that should set off a big red flag that your data is no good.

i did write a tool for doing this, so if you export the logs as CSV with the wideband data, i'd be glad to run static analysis on them for you to help speed the process up?

i know this seems like a lot of work, but it's worth it in the end...

[zoomo]

I greatly appreciate the time taken to explain these things and I agree its worth it. Plus I want to really understand this tuning process, I'm sure this won't be the last car I do.


Now I searched a little but I'm confused on what you mean by CSV? I'm not logging my wideband in anyway yet but I am interested in setting it up. I'll do more searching about this tonight when I get home,if no one answers here before then. Thanks for the help as always

[steveo]

oh it's just a format for your log data, it stands for 'comma seperated values'. i don't log with tunerpro or work with any adx files, i keep all my data in CSV. but tunerpro can export to CSV.. (so can every logging program worth its salt)

you really do need good long logs, and you need to take averages from your data for this to be effective instead of just tuning specific points.

[zoomo]

edit: changed, started tuning it new questions ha.

most important question, at idle, with these settings, my right hand 02 is reading like 100 all the time, left hand like 900, wideband 16 and jumping around. Does that right hand narrowband reading so low all the time indicate the the right hand side is actually running lean? seems to just be at idle.

now im working on adusting the maf tables, its actually really close 13.5-14.2 (except under decel which i assume is normal to go real lean) once these are adjusted how should i go about adjusting my wot air fuel ratio with the pe tables? im confused on how to adjust them because the numbers are so all over the place.


i did some reading about logging the wideband and see i can do it as long as the ac isnt running at the moment so ill get that hooked up tomorrow or so as well.

[lionelhutz]

Personally, I tend to use the closed loop correction factors (ie the block learn or short term fuel trim on a newer system) to tune most of the engine. Good O2 sensors will run the engine at stoichiometric AFR and the correction factors will show how much adjustment had to be made to the base MAF calculation.

The block learns tend to split at idle so you're likely seeing the cause of that with the O2 sensors reading high and low like that. Also remember that it doesn't take much either side of stoichiometric for the O2 sensor to switch. I believe if you close the throttle blades so the IAC is open more it can help.

[steveo]

(except under decel which i assume is normal to go real lean)

yes, i'd usually ignore any events that occur in BLM cell 17 which is most heavy decel. this works for open loop as well.

once these are adjusted how should i go about adjusting my wot air fuel ratio with the pe tables?

you should generally aim for 13-14% fuel added between the total of the RPM and coolant temp tables at operating temperature. that'll hit you 'bout 12.9-13.1 which is usually what people target.

then double check your results with the wideband and tweak your RPM table if there are any areas that go lean or feel limp or whatever.

if you're using an old version of my XDF file, you should switch to the new one, there was a slight error in how PE conversion was done that can throw things off a little bit.

in this one, you go stoich / ( 1 - rpm value + coolant temp value ).

example @ 14.7=stoich, if you have 1.13 in your coolant temp table and 1.00 in the rpm table, that's 13:1. if you have 1.13 in your coolant temp table and 1.01 in your rpm table, you have 12.9:1

attached new xdf just to be sure

[steveo]

here's mine. goes a bit richer on the top end since i don't have a wideband in this car yet, and i beat on it.

[zoomo]

Lion ive searched a lot about the throttle body thing and i see a lot about it on aftermarket it but i don't think you can do it on the stock? i havent looked into it as much as i need to. my idle blms are horribly split like 140 and 118. I just got a little freaked out by the 02 readings at idle.also i guess realistically if it was anything serious it would show up off idle as well.

Steveo, youre a life saver, that other pe adjustment had me all messed up, thats why i went in search of other ways to adjust my wot fuel trim and came up with adusting the maf to accomplish what i wanted.
The new xdf file you sent me looks so much better on those graphs. Looks like im a little more rich than you are, but it shows on the wideband as im running about 12.5 now and its starts getting more rich around 4500 or so.
i gotta get my wideband wired up for logging as its hard to watch it at that point ha.

heres my pe table as of now, ill do some math and adjust it like you suggested and see where i end up.

Thanks as always for the help guys


Edit: well after some help with algebra and a spread sheet from my better half, it seems so simple now ha. I kind of copied steveos a little to keep my numbers closer to one, it simplifies things. According to what we added up it seems like its right at what the widebands reading so hopefully this puts me right around what i need.

[zoomo]

Things seem to be going well. The wideband gets more steady the closer i get things adjusted.

Im struggling tuning the top end ratio though because im not logging the wideband yet.

Can anyone tell me how to change the file in tuner pro to read my aem wideband correctly ? I'm going to wire it into my ac pressure sensor, but I keep reading that it won't read correctly. I haven't found the correction yet.

Thanks as always guys

[steveo]

it's easy to add (just copy your a/c pressure parameter and change the formula), you just need to figure out the appropriate conversion formula for your gauge.

there's no problem with using the a/c pressure sensor input, it's been done many times with LT1 ecms.

however, the linear output on AEM widebands is really really shitty in my experience.

i found i needed to narrow the range of the output in the gauge's firmware (via serial cable) then re-calculate it to get it accurate. even after that i ended up having to just go -0.2 or something so the logs matched the gauge. it was a linear inaccuracy at least and i ended up getting it right.

i had a thread with all the calcs on here somewhere when i was struggling to get it working, i'll try to dig it up.

i found this writeup helpful too, on how to determine the formula for linear voltage to afr

http://www.camaroz28.com/forums/comp...riteup-535603/

[jthompson122183]

the adx from here has wideband setup just need to adjust for setup ($EE-16188051-V3.8.adx) http://www.gearhead-efi.com/Fuel-Inj...rmation-EE-EEBAttachment 8455