I've been thinking of tuning my car / VE table in Open loop just to be able to get the A/F I want at diffrent situations ex. lean crusie. My WB shows 14.3 at cruise now in closed loop.....

I know one way is to raise "min temp to closed loop" but then I always will be in Open loop.

What happens if I set MAX BLM value to 129 and then lower my VE table at cruise to get a higher A/F value? This way you could force the A/F to be leaner?

or any other ideas?

/N.

 

How lean do you want to go? If you just want to "bump" the 14.3 a little (maybe ~15?), you might be able to adjust the O2 sensor calibrations such that the stoich point is biased. Of course, this would be applied all the time closed loop is active. I don't know if your intention is more of a "highway mode" where you run really lean? If that's the case, this probably isn't such a good idea.

If only someone would get moving on the closed loop wideband stuff....

 

You'll probably set code 44s that way.

Might try setting the commanded AFR to what you want, and then dither the rich lean O2 threshold limits. Need a WB to do that thou.

I just go for open loop, with the enable temp set high, and then tune to the AFR I want. Need a WB to do that thou..

For the extra timing, and heat it generates going for a lean cruise can be really hard on an engine. Might try slightly rich, and low timing to see what you get.

 

I agree with the open loop tuning but couldn't he just disable the code 44 diagnostic routine?

 

If you are trying to get more MPG... I would check this post out.

http://www.syty.net/forums/showthread.php?t=15287

Some ideas in there. They took a truck with a mild cam (more lift than stock) and got it to get about 20-22 mpg.

 

I dont think EGR work with a V8 and $58 code?

I have some other issues I have to deal with now but when the car is ready I will try some things in the $58 code........

/N.

 

Actually, there's a "fix" to get the software to execute the EGR code correctly. I believe it was RBob who pointed this out at some time in the past....? Unfortunately, I can't find the post with a quick search (lots of results for $58 and EGR....).

Fortunately, I do remember some details of the "fix". Within the EGR code, there's a reference to the NumberOfCylinders calibration at $C009. On 4 and 6 cylinder engines, this cal is set to a non-zero value. On 8 cylinder engines, it's set to zero. The bin needs to be changed so that $FF is used instead of the calibration ($00) for V8's. I've verified on an ECM bench the EGR duty cycle will change with this fix.

 

Hmm.. I will try that.

I want to go lean at highway becaurse gas is 5.9$/gallon now and climbing

/N.

 

egr patch link

https://www.thirdgen.org/techbb2/sho...highlight=3bar

ED89

 

I hear ya

 

Ok...need to sort some things out, before i try it..

Factor should be set to 1 for The F72 table in Tunerpro, right? just so I get the % values correct.....

The F28 table is as a injector constant and when NOT EGR is enabled $58 uses the value in 0% EGR to calculate fuel, and when the EGR is enabled it uses the other values, correct?


Does the $58 code disable BLM when EGR is enabled?

/N:

Edit: just put in Rbobs "patch" for EGR on V8's.

Addr is: to:

$2E8F $B6 $86
$2E90 $C0 $FF
$2E91 $09 $01

At each of those addresses change the byte to the 'to:' value column.

For the better 100% method, notice that all the code does is to multipy the number of cylinder term by the constant 200. So, lets just do that ourselves and load the result directly.

256 * 200 = 51200, or $C800

And do this:

code:--------------------------------------------------------------------------------
PSHB ; Move D reg to stack
PSHA ;
TSX ; transfer stack addy to X
LDD #$C800 ; for an 8 cylinder
NOP ; fill
NOP ; fill
NOP ; fill
--------------------------------------------------------------------------------


Here is that change in addresses and hex:

Addr is: to:

$2E8F $B6 $CC
$2E90 $C0 $C8
$2E91 $09 $00

$2E92 $C6 $01
$2E93 $C8 $01
$2E94 $3D $01