RonSSNova

iTrader: (3)

Does all of this become moot if you run closed loop idle?
Ron

soundengineer

iTrader: (16)

nope....
you still need the fuel tables to be close...
and you need it to be able to keep all fueling in line... not just part throttle.

as soon as you go WOT.. if you have positive trims..its going to add fuel at WOT no matter what...

RonSSNova

iTrader: (3)

Agree the fueling needs to be in line before turning CL on.

I guess I was thinking more along the lines that you would expect big swings in the idle trims if the bias table wasn't tweaked correctly.

I looked at a few different tune files from various vehicles. They are quite different from each other. No doubt due to the different placements of the IAT sensors.

I never ran my C5 in CLSD, no need as it has a maf. However, the STIT were very well behaved under all conditions.

My turbo 5.3 is not yet running, but will be CLSD, I left the O2 sensors in. I put the IAT reasonably close to the TB, in the charge pipe. I should add another bun in that same pipe in front if the core support and see the differences.

Very informative post.

Btw, my vette runs maf only, and runs very well. I leave the LTFT nanny off. Log every dragstrip run, there have been no fueling surprises.

Ron

James@ShorTuning

On a Gen3 app the OLFA table is used to command an abnormally rich mixture to account for cold engine mixture. Look at all the stock calibrations and you'll see this. There are some after start enrichment tables that can also be tweaked but for the most part OLFA has presidence over it all.

The bias simulates heat soak at low engine speed/airflow by biasing MAT towards ECT because ECT is the engine heat that would transfer to the incoming air and is what heats up the engine bay. This is why it works best when the IAT sees no heat soak.

denmah

iTrader: (2)

anyway to make the ECU go into closed loop with just one 02 sensor bank enabled?

i even have the one sensor, going to both high and low inputs and it still wont close,

i can fire the car and enable closed loop and it trims nice, off the bank1 sensor 1
i set it to trim all cyls, and its in the downpipe, this would be awesome if it would enable closed loop by itself haha

any tricks?

RonSSNova

iTrader: (3)

Factory installations see heat soak though. And by varying degrees. I would think under hood air is more influenced by the exh rather than ECT. Correct?

I bet our turbo setups are worse.

More reason to move the iat

danieloneil01

I took mine off the charge pipe to here.

http://i59.tinypic.com/23tshsk.jpg

soundengineer

iTrader: (16)

that is the exact spot I like to put it when I help a customer/friend with IAT placement

danieloneil01

I wanted to do it on the side but it wasn't flat on the inside where the vacuum nipple was.



PS, don't look at the pictures it suggested I might like based off my intake manifold. lol

soundengineer

iTrader: (16)

I went back and edited my quote to show the actual picture...so people wont have to see the ***** your picture suggests "you might also like"..LOL

you should have used the "IMG Code for Forums & Message Boards" link instead of just the URL.

danieloneil01

I was but I knew the pic would be to big. My IM not what they thought I would like. I've already emailed them to please remove that picture.

slow67

iTrader: (2)

Possibly....Injector Bank Select table.

denmah

iTrader: (2)

I did that. I'm trying the ecu controlled grounds next

soundengineer

iTrader: (16)

the ECU is hard coded for 2
it needs to see a different signal for both sesnors

the way it works is that it runs a routine to add fuel until it swings past stoic, then it takes away furl until it swings past stoic, .... back and forth...

it bascially tries to add on the side where the o2 is...and it follows just fine...
but the other side doesnt do what is expected, and it realizes that, and refuses to go into closed loop


you need both o2 sensors for closed loop

denmah

iTrader: (2)

i gotcha, it wants that pulsing routine

looks lke i will have to add another bung to the downpipe for permanent closed loop to work
thanks for the help!

soundengineer

iTrader: (16)

that will not work either...
you need the o2 sensors in a place where they can read individually...and can each read one side of the engine...

again...
it looks at fuel, and adds or subtracts as necessary...
it adds per bank (1,3,5,7)(2,4,6,8)

so you need one in the drivers side pipe and one in the passenger side pipe
has to happen before the merge of the two.

ls1_chevelle

iTrader: (9)

How are all of the log manifold guys getting away with it?? 1 after the passenger manifold and one just before the turbo(which would technically read all 8 cylinders). But its been done time and time again

slow67

iTrader: (2)

Injector Bank Select table lets you tell the PCM which injectors are tied to which O2. The guys that run SBCs and LT1s with an LS1 PCM modify this table.

denmah

iTrader: (2)

i already tied all injectors to bank1 sensor1

still cant make it go closed loop on its own

HRD

iTrader: (1)

Finding this thread a little late, but I was having issues with my IAT sensor heat soaking after I shut the engine off for a little while then started it back up. It would be lean for a while till the sensor cooled back down. I'm using a screw in sensor that was in the charge pipe just above the radiator. (See photo below) The heat from the radiator was rising up and heating the sensor and the pipe. I found that tweaking the bias tables was not the answer. Relocating the sensor to the outlet of the FMIC was.