Forcing open loop on the 8746
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Forcing open loop on the 8746
Hi,
I am trying to pass the good old Oregon State Sniffer
i treid to force open loop, since i was failing HC's really badly at idle, i figure this is due to the cam, and the false readings of the o2. when i set the closed loop enable temp to 255, it still seemed to correct for lean BL's. i then set the blm enable constants to points that i would never reach, it still seemed like it was correcting (o2 values around .450, HC readings never dropped, no matter what i did the tables). the only way i could get the o2 readings to drop, and the HC's on the test to drop, was to set the closed loop timer to 500seconds, this worked, but i have to get throught the test in those 500 seconds. is there something i am missing in disableing BL corrections, and forcing the computer to run purely off the tables at all times?
I am trying to pass the good old Oregon State Sniffer
i treid to force open loop, since i was failing HC's really badly at idle, i figure this is due to the cam, and the false readings of the o2. when i set the closed loop enable temp to 255, it still seemed to correct for lean BL's. i then set the blm enable constants to points that i would never reach, it still seemed like it was correcting (o2 values around .450, HC readings never dropped, no matter what i did the tables). the only way i could get the o2 readings to drop, and the HC's on the test to drop, was to set the closed loop timer to 500seconds, this worked, but i have to get throught the test in those 500 seconds. is there something i am missing in disableing BL corrections, and forcing the computer to run purely off the tables at all times?
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From: Chasing Electrons
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Re: Forcing open loop on the 8746
Originally posted by Dewey316
Hi,
I am trying to pass the good old Oregon State Sniffer
i treid to force open loop, since i was failing HC's really badly at idle, i figure this is due to the cam, and the false readings of the o2. when i set the closed loop enable temp to 255, it still seemed to correct for lean BL's. i then set the blm enable constants to points that i would never reach, it still seemed like it was correcting (o2 values around .450, HC readings never dropped, no matter what i did the tables). the only way i could get the o2 readings to drop, and the HC's on the test to drop, was to set the closed loop timer to 500seconds, this worked, but i have to get throught the test in those 500 seconds. is there something i am missing in disableing BL corrections, and forcing the computer to run purely off the tables at all times?
Hi,
I am trying to pass the good old Oregon State Sniffer
i treid to force open loop, since i was failing HC's really badly at idle, i figure this is due to the cam, and the false readings of the o2. when i set the closed loop enable temp to 255, it still seemed to correct for lean BL's. i then set the blm enable constants to points that i would never reach, it still seemed like it was correcting (o2 values around .450, HC readings never dropped, no matter what i did the tables). the only way i could get the o2 readings to drop, and the HC's on the test to drop, was to set the closed loop timer to 500seconds, this worked, but i have to get throught the test in those 500 seconds. is there something i am missing in disableing BL corrections, and forcing the computer to run purely off the tables at all times?
RBob.
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I was helpin him try to get through the sniffer, and were were looking for O2 Swing points in the code.
Couldn't find any. Any ideas? Or just keep her in open loop and take out fuel?
Weird thing was, we'd take out fuel run it through, ALMOST pass, take out a smidge more fuel and be back way high on HC again?
What the hell?
Couldn't find any. Any ideas? Or just keep her in open loop and take out fuel?
Weird thing was, we'd take out fuel run it through, ALMOST pass, take out a smidge more fuel and be back way high on HC again?
What the hell?
is 500 secs the max timeout on going CL? coolant temp and time i think are the 2 constants that can be set for closed loop switchover from open. i run a 7747 with tunercat. if you lock open i assume it runs off existing VE tables and the PE adder. how then is PE initiated? i am aware of AE being a function of TPS movement as well as MAP but uncertain whether PE is similar or dependent on RPM's over 3600 to trigger it. i too am considering running open loop only at idle and off idle, when the cam goes in with WB tuning.
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
PE mode comes in a certain % throttle, there may be other things needed for it also though.
the real key to the cam would be some sort of rpm vs o2 swing point, then we could lean out the idle and low RPMs.
the real key to the cam would be some sort of rpm vs o2 swing point, then we could lean out the idle and low RPMs.
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Thread Starter
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
i will have to look into more, and hopefuly the experts will speak up 
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From: Chasing Electrons
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Originally posted by Dewey316
PE mode comes in a certain % throttle, there may be other things needed for it also though.
the real key to the cam would be some sort of rpm vs o2 swing point, then we could lean out the idle and low RPMs.
PE mode comes in a certain % throttle, there may be other things needed for it also though.
the real key to the cam would be some sort of rpm vs o2 swing point, then we could lean out the idle and low RPMs.
Code:
; ---------------------- ; in idle parameters ; ---------------------- LD24C: FCB 132 ; idle mean R/L O2 threshold LD24D: FCB 159 ; idle rich O2 threshold LD24E: FCB 160 ; idle lean O2 threshold
Code:
;*================================================== ;* Mean Rich/Lean Threshold For Unfiltered O2 ;* As A Function Of Flow ;* ;* mV = val * 4.34 ;* Tbl = 230.4 * Vdc ;* (stored in L004E) ;*================================================== LD3CF: ;---------------------------------- ; mvdc ; air flow ;---------------------------------- FCB 120 ; 0 FCB 120 ; 16 FCB 134 ; 32 FCB 134 ; 48 FCB 130 ; 64 ;*================================================== ;* Rich O2 Threshold as Funct Of Air Flow ;* ;* mV = val * 4.34 ;* Tbl = 230.4 * Vdc ;* (stored in L004F) ;*================================================== LD3D4: ;---------------------------------- ; mvdc ; air flow ;---------------------------------- FCB 135 ; 0 FCB 135 ; 16 FCB 138 ; 32 FCB 138 ; 48 FCB 132 ; 64 ;*================================================== ;* Lean O2 Threshold as Funct Of Air Flow ;* ;* mV = val * 4.34 ;* Tbl = 230.4 * Vdc ;* (stored in L0050) ;*================================================== LD3D9: ;---------------------------------- ; mvdc ; air flow ;---------------------------------- FCB 120 ; 0 FCB 120 ; 16 FCB 132 ; 32 FCB 128 ; 48 FCB 128 ; 64
RBob.
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Axle/Gears: 3.42 Eaton Posi, 10 Bolt
Rbob, the first set makes complete sense.
can you explain a little more on the last three tables.
can you explain a little more on the last three tables.
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Originally posted by Twilightoptics
Weird thing was, we'd take out fuel run it through, ALMOST pass, take out a smidge more fuel and be back way high on HC again?
Weird thing was, we'd take out fuel run it through, ALMOST pass, take out a smidge more fuel and be back way high on HC again?
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From: Chasing Electrons
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Originally posted by Dewey316
Rbob, the first set makes complete sense.
can you explain a little more on the last three tables.
Rbob, the first set makes complete sense.
can you explain a little more on the last three tables.
If all else is OK, cat, O2 sensor, plugs, wires, cap, fresh oil, timing, EGR valve (not leaking); 2 gals of denatured alcohol to 8 gals of gasoline . . .
RBob.
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From: Portland, OR www.cascadecrew.org
Car: 1990 Camaro RS
Engine: Juiced 5.0 TBI - 300rwhp
Transmission: T5
Axle/Gears: 3.42 Eaton Posi, 10 Bolt
how exactly is the airflowed figured? it has the addresses for where it gets that information, but is there a way that i can determine what airflow values i have based on my VE tables? something like VE * RPM * 230.4 ?
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From: Chasing Electrons
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Originally posted by Dewey316
how exactly is the airflowed figured? it has the addresses for where it gets that information, but is there a way that i can determine what airflow values i have based on my VE tables? something like VE * RPM * 230.4 ?
how exactly is the airflowed figured? it has the addresses for where it gets that information, but is there a way that i can determine what airflow values i have based on my VE tables? something like VE * RPM * 230.4 ?
The math is:
L002B = ((MapAdc * 189) / 256) + 21
gms/sec = ( (((L002B * 120) / 256) + 18) * (rpm / 12.5) ) / 256
With the final gms/sec value limited to 64. The rpm term in the equation is the actual rpm divided by 25.
RBob.
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Originally posted by Grumpy
You crossed into having a lean miss.
You crossed into having a lean miss.
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Originally posted by Grumpy
You crossed into having a lean miss.
You crossed into having a lean miss.
friday is my day off, so i will be back at the smog station with the laptop...
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