BLM & Integrators & O2 Sensor mv
07-29-2002, 12:18 AM
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BLM & Integrators & O2 Sensor mv
Hello, my name is Brian and I am :confused: right now.
During a 1/4 mile pass my Integrator is 128, my BLM is 138. To me that means "car is lean, ECM adding fuel with BLM". Am I dumb and wrong? If that is the case, shouldn't the O2 sensor be showing readings below 450? They are in the 800s solid for the whole run.
How do you know if the car is in P/E or not?
During a 1/4 mile pass my Integrator is 128, my BLM is 138. To me that means "car is lean, ECM adding fuel with BLM". Am I dumb and wrong? If that is the case, shouldn't the O2 sensor be showing readings below 450? They are in the 800s solid for the whole run.
How do you know if the car is in P/E or not?
07-29-2002, 12:59 AM
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Re: BLM & Integrators & O2 Sensor mv (scorp508)
HI BRIAN
If the BLM value was less than 128 (ECM pulling fuel) when entering PE mode, it is set to 128. If the value was greater than 128 (ECM adding fuel), that value is kept. Reason - do everything possible to avoid lean WOT condition to lessen warranty replacement of engines...
I know PE because the AFR data byte changes from 14.7 to 11.99 in the scan data (Moates SW). The closed loop flag is useless as it only indicates the readiness of all closed loop conditions.
[Modified by Hendej, 11:00 PM 7/28/2002]
If the BLM value was less than 128 (ECM pulling fuel) when entering PE mode, it is set to 128. If the value was greater than 128 (ECM adding fuel), that value is kept. Reason - do everything possible to avoid lean WOT condition to lessen warranty replacement of engines...
I know PE because the AFR data byte changes from 14.7 to 11.99 in the scan data (Moates SW). The closed loop flag is useless as it only indicates the readiness of all closed loop conditions.
[Modified by Hendej, 11:00 PM 7/28/2002]
07-29-2002, 01:46 AM
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Re: (scorp508)
Brian,
I posted in the other thread that has the diacom files, but I'll give you a brief rundown here too so it's in this thread....
Your chip was programmed with larger injectors in mind, but then you ended up with the stockers for now. Since the ECM is expecting more flow, and it's not there, then it thinks you are running lean and that's what's bumping up the BLM.
So, the O2's are in the range they need to be (as close as you can tell with a narrow band O2) but your BLM's think you're running lean. Either get larger injectors or change the injector constant back to stock and things will look a little more normal in Diacom!
:cool:
I posted in the other thread that has the diacom files, but I'll give you a brief rundown here too so it's in this thread....
Your chip was programmed with larger injectors in mind, but then you ended up with the stockers for now. Since the ECM is expecting more flow, and it's not there, then it thinks you are running lean and that's what's bumping up the BLM.
So, the O2's are in the range they need to be (as close as you can tell with a narrow band O2) but your BLM's think you're running lean. Either get larger injectors or change the injector constant back to stock and things will look a little more normal in Diacom!
:cool:
07-29-2002, 01:58 AM
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Re: (scorp508)
No doubt the calibration is different what with your Al heads and all. There is a table that comes into play during PE: % AFR change vs RPM. Mine is set to all 0% change. There is also a table Open Loop % AFR change vs load, but the table doesn't change above a load value of 160 which is probably not enough to reach PE. There is a third one, Open Loop % AFR change vs coolant, but the table values don't change above 100F.
In my calibration, for PE conditions, I get 9% from the load table, 9.8% from the coolant table and 0 from the RPM table. Since 14.7 to 11.99 is an 18.4% change, maybe those three tables account for the AFR I see?
[Modified by Hendej, 12:02 AM 7/29/2002]
In my calibration, for PE conditions, I get 9% from the load table, 9.8% from the coolant table and 0 from the RPM table. Since 14.7 to 11.99 is an 18.4% change, maybe those three tables account for the AFR I see?
[Modified by Hendej, 12:02 AM 7/29/2002]
07-29-2002, 02:16 AM
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Re: (Hendej)
BTW, I'm not certain that the commanded AFR value is anything more than informational. The PW values in my scan files pretty much match up with the PW values in the open loop fueling table of PW vs Ld. I need to make certain that my new injector constant is being taken into consideration. I don't assume anything anymore...
