Orr89RocZ

iTrader: (20)

I just recently started getting into tuning this 383 I've built. its pretty aggressive, specs are in the sig and links in sig.

basically i have 11 to 1 comp 383 with 78 degrees total overlap advertised, 19 at .050" i believe it is

I got a base tune from pcmforless and the car drives well on it. Idle's ok too


here's my situation so far using 1989 165ecm and 6E mask. AUJL bin modded ofcourse

My idle LV8 seems high at between 60-80, it hovers around as the idle is mildly searching. mainly staying between 65-75. I have it set to idle at 900 rpms warm and it seems to stay around 950-1100, lightly surging around alittle. Most of the time its between 975-1050 which is pretty stable

I reset PE mode to engage at 85 LV8 so its not on during idle. Is that bad to have PE mode on all the time? it was set to stock 50 LV8 and the car was idling the same way. When i moved it up to 85, the car went lean and i corrected that so far to get me where i was before air/fuel wise

I reset IAC to have roughly 20-40 steps at idle. MAF gm/sec values are about 15 varying between 14.7 and 15.5 or so.

Injector pulse width at idle varies between 1.3 and 1.5 msec with 42 lb injectors at 42psi. Chip has it set to 42.

LC-1 Air fuel ratio shows 14.4 to 1 give or take .4 as it moves around.

I have about 26 degrees timing at idle

The idle isnt bad nor is it stinky, it has no odor practically. I just want it to smoothen out and hit my target 900 or so rpm idle speed. Car drives well and idles fine ok. Part throttle is between 14-15.5 to 1 air fuel. No real surging at any rpms on the road. I think the base tune was very good and very close. I just want to double check these numbers i'm seeing to see if they fall in line with a hot motor build

IROCZ28dan

Where are your BLMs at?

I assume they are pretty close if you are seeing 14.4 on your wideband, but what do you have stoich set at in the bin? So long as you arent hitting the min/max limits of your BLM boundaries you will most likely continue to see the numbers in and around the 14s for most driving conditions...unless of course you are tuning in open loop...

Your PE shouldnt come on just off idle, unless you max out your MAF that soon which I highly doubt. However, it wont just activate with LV8 only, its also based off of TPS and a few other factors to actually engage.

Your IAC steps look to be spot on. Your slight surging at idle doesn't suprise me with the LSA you are running. Your gm/sec may be just a tad high at idle but considering you are idling up around the high 900s and it really isnt too far off. Getting the rest of the MAf tables in line for a breathing engine like the one youve got will be one of the biggest helps as far as driveability/economy/power output are concerned.

I wouldnt doubt seeing that MAF max out at around 5000-5500, so make sure your PE fueling is on to help compensate for when the computer goes blind...That engine will probably spin to what, 6500+?

Good luck with it! Sounds pretty cool!

Orr89RocZ

iTrader: (20)

correct, BLM's show slightly rich at idle but they arent far off, i think it was 120. part throttle driving was showing similar 120-130 depending, some light throttle went to 112 but air fuel is still showing in the 13.9-14.5 range so i'm pretty good

Stoich is set to 14.69 to 1. My car now goes abit lean in open loop first startup. its 14 ish to 1 then starts to warm up some then jumps to 16 then to 18 pegging my gauge, then drops to 14s to 1 once closed loop, so i guess i'll do some more idle open loop tweaking later on. It was fine until I started playing with some things so i'll have to go back to the base bin

WOT i played with today.. was showing 17ish to 1 at first so i added 10% and it was 16ish... so i added 27% more and it showed somewhere around 14 to 1 but i didnt want to look at the gauge for long, the car realllly picked up speed now with all this extra fuel it needed

But yes, the motor should see 6500 rpms

I'll add probly 10% more and keep it like that till i get to the dyno to compare their wideband with mine

I just wanted to verify my numbers i was seeing

Grim Reaper

Also, make sure you physically re-adjust the IAC as well as bring the Idle speed up with the Desired Idle vs Temp table.

This was all we had to do for a buddy`s solid roller 383 with a Miniram. We got it to idle like glass (well okay, broken glass).

Orr89RocZ

iTrader: (20)

haha yeah right now i'm having problems with cold startup when its still in open loop

it will idle fine tho, just starts at 14 to 1 air fuel and then will peg at 18 but if i blip the throttle alittle idle will normalize and go back to the 14's to 1 air fuel.

Once closed loop comes around, its fine again.

I set my IAC but heres the problem. I did unplug IAC and started motor. I adjusted the throttle body to get the car to idle at desired speed, but i could only get it to hit roughly 700 rpms and it was barely staying alive. My holley 58mm doesnt have enough adjustment to raise it any higher for some reason. Maybe i can get a longer screw?? SO i left it like that and replugged IAC back in. IAC counts dropped alot now, 20's-40 at hot idle instead of like 80

I may lower desired idle speed to the 800's range to see if it likes that any better.

So far i have it set to 1100 on cold start then gradually dropping to 950 then 900 but it usually just stays at 950-1050 reguardless.

My wide open throttle is coming around, got the air fuel in the 13's somewhere so thats a good starting point till i can get it on a dyno and richen it up more. going wide open on the streets just isnt easy anymore

Orr89RocZ

iTrader: (20)

Still having problems with open loop idle so far. Gauge reads 14-15, for alittle while but as it warms up it hits 17-18 again. Closed loop comes in and its around 14-15 once again and usually stays there. idle is still abit erratic

On hot restarts with coolant above 150 or so, it does same thing usually.. open loop idle at first then drops to closed and is fine, but during that open loop phase it peaks at 18 air fuel for alittle untill i start blipping throttle to bring it back down.
What gives?

I increased timing from 23-24 degrees to 28-30, and it seemed to help stabilize idle. I also brought target speed down from 900 to 875 but its still above target...hitting 950 and bouncing around but not all that bad as before.

I played with open loop % changes for LV8 and coolant and nothing seems to cure that rise to lean 18 air fuel upon startup.

I also have that ecm thinking its lean when its on the tad side of rich thing going on. I played with o2 constants and cant seem to cure that either. BLM's were higher at 140-150's but i had 14-14.5 air fuel bouncing around between that. i lowered the milivolt reference tables..both upper and lower and didnt seem to do anything. I put them all the way down to 100 for lower and 210 for the upper and only then did it look like the BLM lowered to 130's or so.
I guess it may want a combination of 02 sensor values and higher MAF values? 78 degrees of overlap on a 383 isnt all that much is it? I have a heated o2

I'll have to keep playing with it.

Grim Reaper

One thing people forget to do, is bump up the manual idle speed via the IAC Screw. This is the idle speed the ECM would go to IF you got certain codes and went into "Safe Mode". It will also be the LOWEST idle speed when you start your engine. This is often a source of "hunting sensation" in the idle.

Follow the same instruction for adjusting the IAC as per the FAQs but instead of 600 rpm, set it to 50 rpm less than your "warm/hot" desired idle speed. EG. If you now are using 800 rpm as your lowest "warm/hot" desired idle speed in the tables, manually adjust the idle speed through the IAC adjustment procedure to 750 rpm. That should solve your open loop problem.

DSmith

What fuel are you running in that thing? I been working on tuning my HSR 383 and with 90 octane I can't run more that 25/27 degrees advance without hearing a lot of clatter when I go wot.

I havn't taken must time with wot tuning and hope that adding some fuel will help.

My idle is set for 700 and sound great with the XFI 280 cam..

Dewayne

Orr89RocZ

iTrader: (20)

I run 93 so far and see no problems with it. I got aluminum heads tho so i can get away with more compression/timing. But i've seen 37 degrees WOT on my base tune and air fuel between 13-16 at WOT and still no noises or knock retard which was weird... I since took it down to 35 degrees and i believe air fuel is between 12.5-13.5 now which is what i want for a base tune when i got to the dyno

problem is my holley idle screw only allows it to go to 600-700 rpms and not 800-900 where i want it. I maxed it out and the engine was struggling to idle at 600-700 rpms. I have no idea if this motor will idle at 800 or not but i guess it couldnt hurt to try that. I just wanted a higher idle to ensure i have good brake vacuum

Grim Reaper

I haven't seen a Holly TB, but the IAC screw is really just a mechanical "idle stop" for the throttle linkage on the TBs I've seen (GM and BBK). The "disconnecting" of the IAC electronics is just to ensure it is seated properly when you adjust the minimum idle speed higher.

Maybe try a different TB? I know that IF we could NOT adjust the idle speed up via the IAC procedure I mention, tuning would have been impossible on my buddy's solid roller.

I hate to say this, but have you eliminated th possibility of leaks? Just for the "fun of it", put on you original TB (if you have it) and see if you can adjust it as I mention and if your idle improves? If it does, then you can eliminate air leak. But, if the stock TB does the same, then I would lean to a leak.

Just throwing out an idea.

Orr89RocZ

iTrader: (20)

No longer have stock TB. I dont believe i have any air leaks but i'm not gonna rule that out. I blocked off all vacuum port spots that i dont use aka cruise control and PCV TB connection (i run a breather now and plugged the TB hole)

I havent tried any idle testing today, so i still have things to try. Definately gonna try the 800 rpm idle speed next

When you say IAC screw, do you mean the screw thats on the throttle body that controls how far open/closed the TB blades are? It acts like a stopper right? I call it the TB idle screw but i guess its very important to the IAC.

IF thats correct then yeah, my TB/IAC screw only pushes out enough to get engine to run 700 rpms which is weird. I'm gonna try lower idle speeds and if that dont work, maybe i'll put a washer in between the TB lever and TB screw stop to raise idle that way and see if it helps. If it does i'll look to change TB screw out to a longer one if possible

Orr89RocZ

iTrader: (20)

tried 800 rpm desired and the car was doing the same thing. IAC counts went alittle lower but still searching and still had that lean condition at first

Its weird now tho. open loop is fine..goes alittle toward 16 but holds back. Then as it enters closed loop the idle pegs lean at 18 to 1 sitting there for alittle while. BLM/INT is 128/128 for like 30 seconds while its in closed loop according to the tunerpro RT. THEN suddenly it snaps out of its frozen mode, and blms/int go up and air fuel goes towards 14-15 again. Idles fine there but BLM's read 150 give or take 5. INT is up 140's too.

SO does that mean it knows its alittle rich and is trying to lean it out? OR does that mean its thinking its lean and trying to richen it up? Is this where the o2 constants come into play?

Out of nowhere today i also got o2 lean code....code 42 i believe it was. It went away tho and didnt seem to effect anything.

Nothing i do to the idle changes these conditions. I'm very confused. Once the car is in hot closed loop after a few seconds and its reading fine, the car idles ok. ALittle surging once in gear and creeping which i dont like. Do i have too much timing now? Any ideas?

DSmith

Just a thought here but what is your "BLM minimum update temp"? Its possible that its set a little too high and doesn't update soon enough and as the engine warms up it burn more of the air/fuel in the cylinders causing it to go lean.

Dewayne

Orr89RocZ

iTrader: (20)

minimum update temp is 122. All of these problems were exerienced on hot restarts when coolant was 150 degrees or higher. No higher than 170 tho.



What is this closed loop O2 timer stuff i see? could changing those values make it assume closed loop faster? I notice hot 02 timer is set to 30 seconds. Does that mean it takes 30 seconds for closed loop to begin once o2 is hot enough and so is the coolant? Cuz it seems to me i'm having this condition for near that much time. I wonder if i make it 10 or something it will update quicker and start closed loop sooner

There is a warm o2 and cold o2 timer which have values of 190 and 300 seconds. Could any of that also effect idle transition from open to closed loop?

DSmith

If I understand it correctly, if your ngine is at or below a certain temp at startup the timer determins how long it takes to go to closed loop. Also you can change the temp setting for warm and hot closed loop at startup.

Orr89RocZ

iTrader: (20)

well doesnt sound like it will fix my condition... as once it goes to closed loop there seems to be a delay with BLM updating and such. Or something because the ecm is showing closed loop but nothign is happening with BLM/INT for a good 20-30 seconds it goes very lean. idle gets rough but still runs.

It may be a o2 constant thing afterall...but i'm not sure

also like to point out, closed loop enable temp is like 104 degrees, but usually doesnt hit closed loop til more like 122-130 i think it was. Why is that? I have a heated o2 by the way

Orr89RocZ

iTrader: (20)

i'm gonna have to read some more of the threads but from what i recall, my problem is not listed in the common big cam stuff

today i've tried everything i could think of and nothing effects this cars idle. I'm almost thinking its not ecm related and has to be a leak or bad o2 sensors but they are brand new

start up is fine at first and slowly goes toward lean. idle is abit rough/erratic when cold coolant. once it starts heating up to running temps of 130-150 degrees startup temps, it idles better but literally 20 seconds give or take the car shoots towards lean and the idle slows down/gets more choppy. idles fine for a few seconds at 14-15 air fuel and then shoots to 16-17-18 pegging the gauge for a little while then shoots back to 15 and rpms jump as hits closed loop mode where it will idle erraticly but not horrible. car surges alot in gear tho, never did that befoer and i never changed the tune. I guess as the motor breaks in it is gonna effect the tune?

But i tried everything. Maf tables, timing, startup enrich/decay stuff, stall saver settings, o2 constants, rich lean fast o2 sensor thresholds, the works

NOTHING WORKS ON THIS MOTOR. i'm thinking it has to be a leak or something but there are only a few vacuum connections and all of them are fine from what i can tell. TB is on with a good gasket and plenum is rtv gasketed to the base manifold.

I'm losing my mind with this tune. its like its getting worse. i even put the stock tune back in where it worked well a few weeks ago upon first startup/drives and now that doesnt even work!!


I did notice my blms reading closer to 128 at idle in closed loop with slow o2 constants set around 150 lower and 250 ish upper. but i am getting lean o2 sensor code 44 on and off occasionally

pandin

$6E Arap

I am not set up as "hot" as you are, I also found the lean off idle when raising the "PE mode to engage at LV8 (04FD)", as long as the TPS change "Minimum %TPS to Enable Power Enrichment" (0501) is under a certain %, (70.31) there will be no PE.

I raised it to "57 LV8" seems better, 65 was too lean.

I also lowered the Closed loop Timer temps and times(0445-044A). With a heated O2 it does not take as long to be ready.

I do an idle data log, from dead cold till it is completely warm, to see what is going on. You can see the O2 wake up and that is when to switch to Closed loop.

Hot timer 34, warm timer 74, cold timer 150, cold timer temp 59F, hot timer temp 158F, and Closed loop temp 104F, I run no cat and no egr.

My idle O2 swings are low causing the ECM to go over rich.

Lowered to the "Closed Loop Rich/Lean Threshold vs. Airflow" to 255 range, also do the upper and lower tables, keep the same spread.

Lower "If 02 Sensor >= 0.19v, then disable ERR 44, (VDC * 226)" (023A)45 = .19v.

Orr89RocZ

iTrader: (20)

ok i reset the ecm by disconnecting battery. Made my open loop AFR vs coolant % change back to stock

lowered my idle spark alittle bit and reset idle rpm lower to i think it was 800 desired but it idles now at 900-950 with alittle searching but not as bad as before

started teh car up and first dead cold startup to warm closed loop was GREAT. just fine, it idled good and never lean spiked

i shut it down and waited a few minutes. Warm restart it starts good and idles good with air fuel of 14-15 like always but literally 10-20 seconds or so into the idle it will go very lean and the car's idle starts to decline and audibly softens. So i kick the pedal abit to get rpms up to richen up the idle. a few seconds of doing this it will go back to closed loop and be fine again

Not sure what is going on with hot restart idle open loop to closed loop transistion. its like there is a coolant temp based table i'm missing that i havent played with or havent used properly yet

IROCZ28dan

I'm not on my computer with tunerpro right now but if I'm not mistaken there is a coolant temp table that was to go with warm restart and the number of IAC steps. Perhaps on a warm restart your IAC steps are too high and causing your lean spike?

Orr89RocZ

iTrader: (20)

i'll have to go back and see the tables and what my iac steps are doing

I now have warm idle IAC steps in the low low range of like 8-13 or something like that. Cold starts i think was much higher

there is a warm IAC park steps added vs coolant.... it goes up from 100 to 75 to 50 to 25, 10, etc as coolant goes up. I may play with that

pandin

What are your O2 counts values doing during this restart? Can you save your data log to excel and graph the O2 mv vs time?

Also consider lowering the "O2 Error Reduction Gain Vs Airflow" table, ARAP (0486 - 048E). Sometimes needs cut by 1/2

Orr89RocZ

iTrader: (20)

i have no idea what the counts are doing, i'll have to check that tomorrow.

how does the ecm read the o2 sensor for open loop tho? i thought it didnt worry about that in open loop?

pandin

The ECM reads all the data when requested to dump, it only uses the values when needed. O2 mv and cross counts are watched (dumped to the aldl link) during open loop, but not used to correct the fuel until closed loop is enabled

Orr89RocZ

iTrader: (20)

playing with some o2 constants yeilds near 128 blms at idle in closed loop, however air fuel is not 16-17 to 1. It eventually works its way back up alittle but for the most part its lean so says the gauge

shouldnt BLM's read alot higher if its actually 16 to 1?

during cruise sometimes its around 14.5 to 1 and still reading near 128 BLM. sometimes works up to 130's when it dips down near 13.5-14.0 to 1. Seems to me that rich would be lower BLM's like 11x's

its like my o2 sensor is flip flopped or is that how it realy works? i always thought BLM/INT above 128 was engine was lean

I think i may have alittle too low 02 slow reference voltage in those upper/lower tables. seemed to help to lower them to get blms' down toward 128 but i think i went to far. they are at like 175 low and 275 high. Fast 02 is just 50mv below stock i'm not sure what fast does

pandin

As the exhaust gasses travel from the cylinder to the O2 sensor, the gas is still burning. This burning is more at higher rpms and less at lower (think back to a short pipe exhaust). Flames will be present out the end of the pipes at higher rpms. At idle the pipe is cooler and very little fuel/air is available for additional combustion (stock cam, heads, and exhaust).

Install a large overlap cam, free flowing heads, and exhaust, more fuel/air is pulled past the combustion chamber into the header/exhaust pipe. This added fuel/air is what makes the O2 (NB, WB) "inaccurate" as to the "true" cylinder head combustion chamber AFR.

Unburnt fuel/air is read by an O2 sensor as, just "oxygen", giving a "lean reading mixture) when in fact the mixture is "rich".

The O2 (NB, WB) only reads the "Oxygen" content of the passing gas "at the sensors installed location". As this burning gas is traveling down the pipe, it is consuming the oxygen and becoming a "richer reading mixture".

A WB is a NB O2 with more "sensing elements", the WB's NB part is the base line for the WB's output.

When "playing with" O2 swing points vs a WB reading, remember that the, placement of the sensors, affects the readout. Down the pipe will be after more burning and up the pipe after less burning.

The challenge of "Hot Rod" engines is "calibrating" the ECM/Eprom and O2 output (via O2 swing points, Maf scales, or SD VE) to the "true" cylinder head combustion chamber AFR (what the engine wants). The stock tune is made to keep a fire burning in the cat, not strictly for the "best" running engine. That is why the "new stuff" has pre and post cat O2's.

The AFR numbers are only guide lines "to get get you close" to the "true" cylinder head combustion chamber AFR (what the engine wants), which is hard to measure with "cheap long term sensors" (think of a test stand dyno and a room full of sensors and computers).

Most of the AFR tables are made under "ideal" steady state conditions.

Somebody using a test engine said "this really works with these readings", but this is conditional to the "as tested" engine. If your motor is not an identical twin of the engine he used, yours could be different (think of all the "production tolerance" differences).

The 128 blm is a function of the rich (upper), mean (threshold), and lean (lower) swing points being above or below the actual O2 readings (filtered and averaged).

I use statistical analysis to find the max, min, mean (median), average, and standard deviation, then use these numbers to adjust the swing points (which are there to keep the cat fire burning), gains, and offsets.

Orr89RocZ

iTrader: (20)

well i still cant figure out why this car idles fine for a few seconds after any warm startup after the first startup of the day

After resting all night, i will start it up and it will idle fine in both open and closed loop. After it enters closed loop for the first time i will shut it down. if i restart it again after a minute of rest it will fire up fine and idle good for a few seconds then go very lean and stick there for awhile. it will enter closed loop, still at very lean then eventually kick back up to proper air fuel ratio

it doesnt matter what temp i'm at. i could be at 130-170 when starting and its the same stuff, starts ok, then goes lean for awhile and the car wants to stall. I have to let it idle and free rev it on and off til the air fuel gets back to normal and i can go drive it again. its annoying when your trying to make a few stops when driving and have to go thru this crap.

i have NO clue what else to try except maybe keeping it in open loop all the time and avoid that transition zone. But the car is absolutely fine in closed loop once its in there. Idles fine and even in gear i have it working well

I also noticed my commanded idle air fuel ratio is not exactly the same as the wideband is showing. I wonder if that has anything to do with it.

i also notice i'm idling in BLM cell 1 and every now and then cell 0 will pop in. I have to check to see if thats happening during startups after the first one and if thats causing the lean condition

i am gonna go play with it some more

Orr89RocZ

iTrader: (20)

also notice during this condition, my pulsewidth goes lower to 1.1-1.2 ms instead of normal 1.4-1.5

Orr89RocZ

iTrader: (20)

narrowed it down. its got something to do with my closed loop settings but i dont think its the o2 sensor stuff or it could possibly be that as i havent tried all teh settings yet

I forced open loop and the car ran fine. adjusted maf values to match the wideband airfuel with the commanded..i have it pretty close. Idled fine, never did that lean spike thing

now in closed loop the first minute or so its lean spiked, but it will eventually work fine again and go to commanded airfuel.

WHAT table or whatever is effecting this do you think? I notice my o2 millivolts are always jumping around high/low like it should. It will sit at a value hovering between that value +/- 30mv or so. cross counts stop then start up again and i see it go back and forth like 190 to 700 and such. So thats normal. When its doing this its fine airfuel wise. as it sits at a value it starts to show more lean but doesnt go to that huge spike as before

idk what to do about that. when i first start it up before going to closed loop, its o2 mv readings are in the mid high 600's. it stays high for awhile then finally drops to 200-300's range and air fuel comes back up to where it needs to be

Any ideas??? why is it staying high for a while then coming back down? I've never heard of this problem before

pandin

Mine does the same as yours.

One thing to try is moving the cell boundaries to keep the idle in one cell or to split the cells high idle vs low. Mine are set to 900 rpm and 15 grs/sec this leaves the "0" cell in charge during normal idle, park and drive (750-550 rpm)

I also set the high boundaries to 2400 rpm and 60 grs/sec so it doesn't toggle at normal cruise (6-10 cells).

Orr89RocZ

iTrader: (20)

mine is set to 900 and 15grs/sec as well and my idle is 900-1000 so i'll bump that up i suppose

Orr89RocZ

iTrader: (20)

didnt help any. I just set it to open loop now and its running better so i'm not gonna bother with closed loop at this time

i'll have to tweak the open loop stuff alittle to better match my commanded values but atleast i can start it up at anytime any temp and not have it lean spike and stall out on me

gta324

NBO2 is affected by EGT, maybe has something to do with your problem?

Here is a screenshot of my engine, last year.

- Idle, closed loop (heated O2)
- Blue line BLM
- Purple WBO2

BLM goes low (rich by NBO2) -> WBO2 gets lean...

didnt logg the EGT but it followd the same pattern.

Orr89RocZ

iTrader: (20)

maybe that could be it, since it seems to work once it gets very hot. But even if the car is running along time and i shut it off for 4 seconds and start it up again, it will do the same thing.

I have a heated o2 sensor as well so it should beable to read whats going on. The only thing i wanted to try was use the wideband's narrowband simulator to send the signal to the ecm

RBob

iTrader: (1)

Take a look at the INT & BLM. They will tell you what the ECM is seeing from the O2 sensor. It may also be the SAM cells are being used. Or that the O2 isn't really ready yet. In this case you can increase the delay time before going closed loop.

RBob.

pandin

Here is a Chart of a data log that shows what you are talking about, taken 07 20 2008 (my last log before TV valve stuck in tranny and caused 4000 rpm part throttle shifts)

Orr89RocZ

iTrader: (20)

the way i had the o2 constants, it would vary. But when i put them close to stock to start over, they were both low. BLM 108 and INT below 100. once it gets hot it goes to like 140's blm and 126-128 INT.

I can get BLM near 128 with o2 constants

pandin

From thread: 02 swing points Q?

Quote

"Another way to look at it: during closed loop operation the stoich AFR is used in the PW calculation. This is to create an initial PW. This PW is then modified with the INT & BLM values (and proportional gains), to create the PW used at the injectors.

The feedback from the O2 sensor is used by the ECM to aim at the target AFR. The fueling will be changed (via INT/BLM) to move the PW to the targeted O2 switch point (the window).

The bottom line is that in closed loop operation the ECM is always targeting the O2 switch point(s)."

RBob.

Orr89RocZ

iTrader: (20)

that make sense and is exactly what i was seeing, however it still didnt matter if my blms were correct or not, the car started up fine, and lean spiked for awhile before going back to normal

my guess is that it has to be o2 closed loop timer...it must not be fully ready when the ecm tells it its ready. i have it set to stock 30 seconds for hot o2 closed loop timer.

There is also a o2>x then o2 is ready and o2<x o2 ready constants but i'm not sure what they do, havent explored them

i will try closed loop again but i'll run open for now

pandin

These are values that the O2 sensor mv's have to cross to be "ready", this "ready" is a data log output (My Auto Xray displays it).

My guess is the O2 has to be "ready" before going into closed loop.

When the ECM goes into closed loop there is a mismatch between the initial closed loop settings and the open loop settings. This shows up as a "step" right at the transition and after till the ECM can readjust.

This is because both the Maf tables and the O2 swings were adjusted, and now are out of sync with each other.

Lowering the O2 swings brings the fuel down (this is a ratio change, less fuel same air), so the engine runs "leaner", BLM's will drop. But now the commanded 14.7 AFR is something leaner, based on the leaner/lower O2 swing.

Lowering the Maf tables lowers the "calculated" air and also the fuel (keeping the same ratio, less air and fuel). Since there is more "real" air then the "Calculated" air the engine runs leaner, BLM's will also drop (I am not sure what the O2 swings do, or why the ECM doesn't just adjust it back, this adjustmnet is a very common one to make to lower or raise the BLM's.