cos3 semi closed loop

[kostelacd69]

my 2001 silverado that has cos3 in it will not go into semi closed loop. ive read all the forums and tried a buntch of stuff and still no luck. im tryin to get stft and the only way ive been able to do that is by putting it into full closed loop. any ideas?

[hquick]

Post your tune.

[kostelacd69]

here it is

[5.7ute]

Check out A0008 where you reach operating temp. Its influence will prevent stoich from being commanded which is necessary for semi closed loop. Try setting this to 1.00 from 70 degC & see how that goes.

[joecar]

Fix these up:


Out of Range calibration summary: 09:16:48 pm, Tuesday Apr 21, 2009

EFILive Custom Calibrations
{A0001} Forced Octane Scaler Percentage, was out of range when loaded.
{A0002} Octane Scaler Limiter, was out of range when loaded.

Engine Calibration.AIR Pump
{B0203} AIR Pump Coolant Temp Disable, was out of range when loaded.

[joecar]

+1 on what 5.7ute said about A0008 (which is a multiplier to B3647).

[kostelacd69]

you guys are frikin great i did what you said and it now uses stft thanks a million

[5.7ute]

No worries, glad you got it sorted.:cheers:

[Highlander]

Now that we are on the subject...

It bothers me that with the STFTs only they will cycle to 0 every once in a while and when you read the wideband its a bit inconsistent with the fueling.

[5.7ute]

Now that we are on the subject...

It bothers me that with the STFTs only they will cycle to 0 every once in a while and when you read the wideband its a bit inconsistent with the fueling.

Do you have any logs of this occuring you can post?
I assume this is occuring even with the switch points dialled in to the wideband.

[Lextech]

Here is an answer from Ed Wright about fuel trims and W/B readings. "THIS IS FROM ED WRIGHT--I MAKE NO CLAIM TO IT" I'm just passing the info on.

"Don't use a W/B for Non WOT tuning, you're wasting your time. Use fuel trims--Ed Wright"

"If you want to use a W/B for part throttle and idle tuning---Which I don't suggest(you will be very lucky if your fuel trims agree with your wide band) you need to turn off the air/fuel ratio toggling the PCM does most all the time.
To shut that off, set the P.E. minimum temps and RPM to zero, P.E. enable throttle angle to all zeros, and the P.E. vs RPM Air/Fuel multiplier table to all "1"s and the P.E. vs temp table to all zeros. Otherwise your wide band is likely going to be showing you junk numbers, which may or may not be even close to correct. Even then, many of the popular wide bands vary widely.
You would be better off using fuel trims. Wide bands (Accurate ones that is) are only for WOT tuning. If you set the P.E. like I listed you may very well find it is not lean where it now shows it to be lean.


Are you going to leave your vehicle in open loop all the time? If not, as I said before, your wasting your time. The PCM is still going to try to correct it. I'm betting you will eventually find your not lean where you now think you are. Rich will make one "bog down" the same as lean. Bogus lean numbers is what you will see at idle and part throttle, Never Bogus Rich. Less than half the vehicles I have tested over the years will show 14.7-1 air/fuel at idle and part throttle with a wide band. That is unless you set the P.E. parameters as I outlined earlier. That is due to the wide band trying to deal with the rich/lean toggling. See if you have some black on your spark plugs. The PCM won't toggle the fuel rich, lean, rich, lean in P.E. mode. It does that pretty much all the time otherwise. It does that to store oxygen in the cats. Even if you turn C.O.T. protection off, it still does that. If you want your wide band to be correct (assuming it is), put it in full time P.E. mode while you are trying to do your VE tables. When you re finished, and put it back into closed loop, you may very well find (as many others have) that your fuel trims are again whacked. Many guys are trying to tune these like you would a FAST, Bigstuff3, DFI, etc. Those don't toggle the air fuel Rich/Lean like the factory PCM. They aren't as complex as factory computers,and aren't intended for vehicles with cats."

Jeff

[nevinsb]

I don't exactly agree with that. You will see a "bogus rich mixture" if you have a lean misfire condition.

[joecar]

Is Ed saying to enable PE during PT CL and use LTFT's to tune...?

I need a shorter summary of that...

[kostelacd69]

how would i use stft to tune and not the wo2 can a make a map or what sorry im new

[joecar]

Oh... it seems to me that Ed is saying:
- set PE to enable always,
- set PE to stoichiometric,
- now the wideband would show a flat AFR rather than an AFR that cycles tightly around stoichiometry.

The PCM would still be in CL and be in PE at the same time, would that be right...? (interesting)... the PCM would get the AFR from the PE table... and would trim to it but not using the stoichimetry crossings... is this what Ed is saying...?

[joecar]

how would i use stft to tune and not the wo2 can a make a map or what sorry im new
Hi K,

You would disable CL, enable short term triming, map a map of something like 1 + (STFT1 + STFT2) / 400 and apply this to VE or MAF...

but this would only work where the AFR is close to stoichiometry... you can't tune WOT like this since the AFR at WOT is too far from stoichiometry.

[kostelacd69]

right now im tuning wot with my wideband but i havent put my narrow bands in yet so its all been tuned with the wb. i want the stft to work so it has better fuel milage and driveablity. when i put them in i just have to get a map made. can you send me a copy of your map so i can see what you mean thanks

[joecar]

What wideband do you have...?

[kostelacd69]

ive got an intovative the hand held one its what ive been useing for years to tune all my carb stuff. yeah big jump i know

[mr.prick]

Is Ed saying to enable PE during PT CL and use LTFT's to tune...?

[QUOTE=Lextech;97941] "Don't use a W/B for Non WOT tuning, you're wasting your time. Use fuel trims--Ed Wright"
/QUOTE]

It sounds to me that he is saying use LTFTs for non PE
and WBO2 for WOT.
Like this: CLSD tuning with LTFTs (http://forum.efilive.com/showthread.php?t=10981&highlight=LTFTben)
I personally agree with this method, it works for CLSD and CLMAF.
Not only will your LTFTs be inline and
your WOT AFR will be nearly spot on (as long as LTFTs are negative before PE)
but your VE and MAF tables will be smooth if tuning on the street.
You can use the "standard" autoVE process to get your VE table
into the general shape it needs to be with cam and heads/stroker
then use LTFTs and WOT to get it perfect.

Of course filtering is important with this method.
There is no need to use OL all the time,
unless you want to use an emulator to keep fuel perfect.
This is fun and can give you many hours of fun but not
practical for a DD.

My 2¢

[joecar]

Ed said to make PE be enabled while doing this, I am wondering what this does.

[5.7ute]

I can understand his methods would make it easier as a professional tuner with time constraints. But dont agree with his logic that fuel trims will mess up your part throttle & WOT tuning afterwards if you use a wideband at part throttle. If you dial in your o2 sensor switchpoints, you should be able to get your narrowband sensors to correlate with the wideband. This will stop the fuel trims from messing with your finished tune.

Joe, I believe he wants PE enabled to prevent any chance of the pcm entering closed loop. Just another way to skin the proverbial cat.

[joecar]

So if the PCM is in PE mode it cannot be in CL mode, as a matter of convenience...

[hquick]

So if the PCM is in PE mode it cannot be in CL mode, as a matter of convenience...

That's the impression I get.

[Cablebandit]

hmmm.....im confused.....if you put the commanded afr to stoich in pe mode, would it switch to closed loop?

[kostelacd69]

so i got another one that wont go into semi close loop any help would be great

[5.7ute]

Can you post a log file?

[kostelacd69]

here it is

[5.7ute]

There is nowhere on that log where you are commanding stoich. This is necessary for STFT to become active.
This is because you are commanding leaner than stoich in the cruise cells in the tune.

[kostelacd69]

your exacly right but i cant find anywhere in the tune that would be making it come out of the fuel vs rpm table. thats where im stuck.

[5.7ute]

look at B3647.1200rpm to 2800rpm in the 35 to 70 kpa map zone. You will need to set these to 14.68 for STFT.(EQ 1.0)

[kostelacd69]

thats wierd because i can set the table to be 13.5 and when it gets there it stops triming but when it goes back to anywhere that says 14.68 it starts triming again. thats on my truck i mean. this one that were looking at is a buddys.

[5.7ute]

In that last log there was nowhere 14.68 was commanded long enough for STFT to ocur.
IIRC it only flashed through stoich briefly maybe 2 times.

[kostelacd69]

ok yeah ill try that then thanks ill let you know

[64camino]

I think the question is whats keeping it from commanding stoich when it's not in the 1200-2800 35-70 kpa zone.

[kostelacd69]

yeah that is the questions but if its not in the 14.68 for long enoght it wont have time to start triming right? but mabye on start ups only will it have that problem because it takes 30 seconds or so for it take start triming after u start the first time not about during a run.