well I put the heated o2 on my car and I still read lean @ idle.



with the heater not hooked up to power it acts like a regular non heated o2 (hold on befor you go wow never would have guessed that one ) what I am getting to is it reads around 300-400 or so mv but, when I plug it in to power and let it warm up the mv drop very low 40-70 mv area and the ecm jumps the idle up and starts hunting and is still unable to bring the mv up. which is worthless since I can tell by the plugs and smell I am not lean.


now I have a cam that has a good lope to it and I know that it is pretty common to have issues with o2 sensors and valve overlap showing a real lean idle. even though you are dumping fuel. now the question is how do you tune a car that has these issues?

won't a wide band show a lean condition as well? do I use primary temps to tune or do I have to get a 5 gas and read plugs at an incredable price for gasket seat AC plugs

 

Absolutely. Both reversion and improved scavenging adds unburned air to the exhaust gas. If your system uses a narrow band sensor, you will only be able to tune it (correctly) in open loop. As soon as the loop closes, the O2 sensor's erroneously lean readings will tell the computer to increaase the pulsewidth. This is because the O2 sensor is not seeing only the actual burned charge but the additional scavenged air and/or reversion air. It is for this reason that the LS2 and LS6s have a large camshaft LSA (116 degrees). Essentially this means that while the exhaust AFR is 14.7:1, the actual combustion mixture is much richer. The bottom line is that once you've improved exhaust flow, your closed loop mixture is going to be rich. Idle and cruise will suffer most because of the high level of reversion.

 

I thought there was a table in 6e that said had "closed loop enable vs coolant temp " or something along those lines but, I can't find it. how do the 6e guys keep it in open loop?

 

'dis one:

RBob.

 

The minimum temperature settting for closed loop is at address 445h. Normally this is set to 6bh. The formula is: t = 0.75n - 40 (in degrees C). What you would do is move it up to something like 200h (230 degrees)F. Remember though, if you do this, you will always be in open loop.

 

Thanks a ton guys

 

I'm having the same issue at idle - closed loop is killing me. I e-mailed Mark Mansur to see if there was an "RPM to enable closed loop" parameter in TunerPro that I was missing, but there is not. However, Craig Moates suggested a "back door" way of getting there (in $6E):

Since Power Enrichment mode is technically "open loop", you could set the "Min % TPS to enable Power Enrichment" to "0" for 400 and 1200 rpms. Then, you would set the "% Enrichments" in the "Power Enrichment vs. RPM" table to "0" through 1200 rpm. I believe this would effectively put the ECM in open loop for anything below 1200 rpm. I haven't tried it yet, but it could be worth a shot.

There is also the "Closed Loop Rich/Lean Threshold vs. Airflow" parameter - you might be able to lower the O2 threshold for the air flow numbers you typically get at idle. Again - it could be worth some trial and error.

 

I am using tuner cat tdf editor, and I want to make sure I am doing this right.



8bit

constant name - Min Temp for Closed Loop
constant units - Deg. C
Constant location Hex- 445

scaling,

Expoential Scale factor - 1
Constant Scale Factor - 0.75
Constant modifier- -40

Editor Limits,

Edit step size - 0.75
Minimum value - -40
Max value - 151