No lean correction off idle... again!
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Car: '85 maro
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Transmission: TH700 R4
Axle/Gears: 3.73 posi
No lean correction off idle... again!
Well I'm not certain why this problem's reared it's head again, but ever since I installed a t-bird maf on my car it will only correct lean conditions at idle and low cruise. Also, I've noticed that it only shifts between blm cells 0,1,5 and 10 where it stops correcting in 5 and 10. It will lean things out just fine everywhere, but it hits a ceiling at 128int in those cells. What could cause this?
Joined: Jul 2000
Posts: 1,519
Likes: 18
From: Fort Myers, FL
Car: 91 Firebird
Engine: 6.0
Transmission: T56
Axle/Gears: 3.73
Re: No lean correction off idle... again!
I would plug the stock maf back in and see if the problem goes away.... The ECM may just not like the T-bird maf......
-jason
-jason
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Joined: Sep 2007
Posts: 350
Likes: 15
Re: No lean correction off idle... again!
ccp chg?
LC017: FCB $08 ; 0000 0000 4th AIR FUEL MODE WORD
; Bit 0 = Use LV8 for BLM not dispflow
; 1 = not used
; 2 = 4th Gear Hwy Mode Spark Adv check enabled
; 3 = If CCP Chg, force Int to 128
;
; 4 = TCC locked Hwy Mode Spark Check enable
; 5 = N.O. Cooling Fan Req input
; 6 = Pwr Steer Pressure Sw installed
; 7 = Use TCC out to Cnt'l A/C Clutch; Bit 0 = Use LV8 for BLM not dispflow
; 1 = not used
; 2 = 4th Gear Hwy Mode Spark Adv check enabled
; 3 = If CCP Chg, force Int to 128
;
; 4 = TCC locked Hwy Mode Spark Check enable
; 5 = N.O. Cooling Fan Req input
; 6 = Pwr Steer Pressure Sw installed
or how about this:
LC568 FCB 4 ; 17 mvdc, Min Error To Implement Int.(VDC * 226)
Closed loop?
O2 Ready?
Learn control enabled?
Anything strange in your error tables?
;---------------------------------------------
; Upper 0 error for Slow 02 Vs Air flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC56C FCB 140 ; 619 0
LC56D FCB 148 ; 655 8
LC56E FCB 152 ; 673 16
LC56F FCB 152 ; 673 24
LC570 FCB 148 ; 655 32
LC571 FCB 144 ; 637 40
LC572 FCB 132 ; 584 48
LC573 FCB 132 ; 584 56
LC574 FCB 132 ; 584 64
;---------------------------------------------
;---------------------------------------------
; Lower 0 error for Slow 02 Vs Air flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
Page 51
ABTC_HAC.SRC
ORG $0575 ; o2 ERR gms/Sec
;---------------------------------
LC575 FCB 120 ; 531 0
LC576 FCB 128 ; 566 8
LC577 FCB 132 ; 584 16
LC578 FCB 132 ; 584 24
LC579 FCB 128 ; 566 32
LC57A FCB 124 ; 549 40
LC57B FCB 112 ; 496 48
LC57C FCB 112 ; 496 56
LC57D FCB 112 ; 496 64
;---------------------------------------------
;---------------------------------------------
; Fast o2 Rich/lean Treshold vs Air Flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
ORG $057E ; o2 ERR gms/Sec
;---------------------------------
LC57E FCB 130 ; 575 0
LC57F FCB 138 ; 611 8
LC580 FCB 142 ; 628 16
LC581 FCB 142 ; 628 24
LC582 FCB 138 ; 611 32
LC583 FCB 134 ; 593 40
LC584 FCB 122 ; 540 48
LC585 FCB 122 ; 540 56
LC586 FCB 122 ; 540 64
;---------------------------------------------
;---------------------------------------------
; Integrator Delay Vs Air flow
;
; Table value = Sec's * 80
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC587 FCB 32 ; 0
LC588 FCB 28 ; 8
LC589 FCB 24 ; 16
LC58A FCB 22 ; 24
LC58B FCB 20 ; 32
LC58C FCB 18 ; 40
LC58D FCB 16 ; 48
LC58E FCB 16 ; 56
LC58F FCB 16 ; 64
;---------------------------------------------
;---------------------------------------------
Page 52
ABTC_HAC.SRC
; Slow o2 Filter Coef Vs Air flow
;
; TBL = Mult * 256
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC590 FCB 16 ; 0
LC591 FCB 24 ; 8
LC592 FCB 32 ; 16
LC593 FCB 36 ; 24
LC594 FCB 40 ; 32
LC595 FCB 44 ; 40
LC596 FCB 44 ; 48
LC597 FCB 44 ; 56
LC598 FCB 44 ; 64
;---------------------------------------------
;---------------------------------------------
; o2 Error Reduction Gain Vs Air flow
;
; TBL = Mult (0-1) * 256
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC599 FCB 200 ; 0
LC59A FCB 224 ; 8
LC59B FCB 236 ; 16
LC59C FCB 244 ; 24
LC59D FCB 248 ; 32
LC59E FCB 255 ; 40
LC59F FCB 255 ; 48
LC5A0 FCB 255 ; 56
LC5A1 FCB 255 ; 64
;---------------------------------------------; Upper 0 error for Slow 02 Vs Air flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC56C FCB 140 ; 619 0
LC56D FCB 148 ; 655 8
LC56E FCB 152 ; 673 16
LC56F FCB 152 ; 673 24
LC570 FCB 148 ; 655 32
LC571 FCB 144 ; 637 40
LC572 FCB 132 ; 584 48
LC573 FCB 132 ; 584 56
LC574 FCB 132 ; 584 64
;---------------------------------------------
;---------------------------------------------
; Lower 0 error for Slow 02 Vs Air flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
Page 51
ABTC_HAC.SRC
ORG $0575 ; o2 ERR gms/Sec
;---------------------------------
LC575 FCB 120 ; 531 0
LC576 FCB 128 ; 566 8
LC577 FCB 132 ; 584 16
LC578 FCB 132 ; 584 24
LC579 FCB 128 ; 566 32
LC57A FCB 124 ; 549 40
LC57B FCB 112 ; 496 48
LC57C FCB 112 ; 496 56
LC57D FCB 112 ; 496 64
;---------------------------------------------
;---------------------------------------------
; Fast o2 Rich/lean Treshold vs Air Flow
;
; Table value = mvdc * 0,226
;---------------------------------------------
ORG $057E ; o2 ERR gms/Sec
;---------------------------------
LC57E FCB 130 ; 575 0
LC57F FCB 138 ; 611 8
LC580 FCB 142 ; 628 16
LC581 FCB 142 ; 628 24
LC582 FCB 138 ; 611 32
LC583 FCB 134 ; 593 40
LC584 FCB 122 ; 540 48
LC585 FCB 122 ; 540 56
LC586 FCB 122 ; 540 64
;---------------------------------------------
;---------------------------------------------
; Integrator Delay Vs Air flow
;
; Table value = Sec's * 80
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC587 FCB 32 ; 0
LC588 FCB 28 ; 8
LC589 FCB 24 ; 16
LC58A FCB 22 ; 24
LC58B FCB 20 ; 32
LC58C FCB 18 ; 40
LC58D FCB 16 ; 48
LC58E FCB 16 ; 56
LC58F FCB 16 ; 64
;---------------------------------------------
;---------------------------------------------
Page 52
ABTC_HAC.SRC
; Slow o2 Filter Coef Vs Air flow
;
; TBL = Mult * 256
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC590 FCB 16 ; 0
LC591 FCB 24 ; 8
LC592 FCB 32 ; 16
LC593 FCB 36 ; 24
LC594 FCB 40 ; 32
LC595 FCB 44 ; 40
LC596 FCB 44 ; 48
LC597 FCB 44 ; 56
LC598 FCB 44 ; 64
;---------------------------------------------
;---------------------------------------------
; o2 Error Reduction Gain Vs Air flow
;
; TBL = Mult (0-1) * 256
;---------------------------------------------
ORG $056C ; o2 ERR gms/Sec
;---------------------------------
LC599 FCB 200 ; 0
LC59A FCB 224 ; 8
LC59B FCB 236 ; 16
LC59C FCB 244 ; 24
LC59D FCB 248 ; 32
LC59E FCB 255 ; 40
LC59F FCB 255 ; 48
LC5A0 FCB 255 ; 56
LC5A1 FCB 255 ; 64
Last edited by tequilaboy; Nov 12, 2008 at 11:30 AM.
Thread Starter
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Car: '85 maro
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Transmission: TH700 R4
Axle/Gears: 3.73 posi
Re: No lean correction off idle... again!
All those things check out aside from the fact that I have the O2 boundaries set to 402, 451 and 500 to match my wb settings and the reduction gains set low to cancel out the afr swings for the catcon I don't have. I'd rather get this thing operating the way it should so I'm going to leave the maf tables alone (although I'm not certain of how accurate they are anyway).
Thread Starter
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Car: '85 maro
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Re: No lean correction off idle... again!
Here's what I have in my maf tables. (conversion math for all tables is X * s / 255 where s is table scalar)
Table 1 (scalar = 15)
15.00
11.76
9.12
6.94
5.12
3.53
2.18
1.00
0.00
Table 2 (scalar = 35)
35.00
31.98
29.10
26.35
23.61
21.00
18.80
16.75
14.96
Table 3 (scalar = 69)
69.00
62.51
56.01
50.60
45.73
41.67
38.69
36.26
34.91
Table 4 (scalar = 118)
118.00
109.67
102.27
94.86
88.38
82.37
77.28
72.65
68.95
Table 5 (scalar = 191)
191.00
179.76
169.28
159.54
149.80
140.82
131.83
124.34
117.60
Table 6 (scalar = 255)
255.00
255.00
255.00
255.00
255.00
247.00
240.00
234.00
228.00
222.00
217.00
212.00
207.00
202.00
198.00
194.00
191.00
Table 1 (scalar = 15)
15.00
11.76
9.12
6.94
5.12
3.53
2.18
1.00
0.00
Table 2 (scalar = 35)
35.00
31.98
29.10
26.35
23.61
21.00
18.80
16.75
14.96
Table 3 (scalar = 69)
69.00
62.51
56.01
50.60
45.73
41.67
38.69
36.26
34.91
Table 4 (scalar = 118)
118.00
109.67
102.27
94.86
88.38
82.37
77.28
72.65
68.95
Table 5 (scalar = 191)
191.00
179.76
169.28
159.54
149.80
140.82
131.83
124.34
117.60
Table 6 (scalar = 255)
255.00
255.00
255.00
255.00
255.00
247.00
240.00
234.00
228.00
222.00
217.00
212.00
207.00
202.00
198.00
194.00
191.00
Member
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Posts: 350
Likes: 15
Re: No lean correction off idle... again!
Sounds as if your thresholds are offset towards the lean direction.
Maybe you're just not getting enough lean O2 error due to the offset thresholds and low error reduction gain settings to drive the integrator up. It seems plausible, anyhow.
Maybe you're just not getting enough lean O2 error due to the offset thresholds and low error reduction gain settings to drive the integrator up. It seems plausible, anyhow.
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Re: No lean correction off idle... again!
I've programmed the stock gains in and that didn't make a difference either. 450mvolts = stoich on my wb, so 1mvolt should'nt make a difference but maybe offsetting the thresholds is what I need to do. From what I understand GM purposely offset the target mvolt slightly rich of stoich to keep the int from 'settling'.
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Re: No lean correction off idle... again!
Well that didn't help. Didn't expect it to but I'm grabbing at straws right now.
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Re: No lean correction off idle... again!
How lean is it O2 sensor voltage wise?
For comparison purposes:
Looking at my logs, I need to see the O2 sensor voltage drop below approx. 250 mv before I ever see the integrator increment up.
My own O2 thresholds are offset down (lean) as well by approx. 75-125 mv depending upon airflow compared to the stock settings in an effort to run a little leaner in closed loop. It seems that the error needs to be quite a bit below the theshold to have an effect on the integrator.
For comparison purposes:
Looking at my logs, I need to see the O2 sensor voltage drop below approx. 250 mv before I ever see the integrator increment up.
My own O2 thresholds are offset down (lean) as well by approx. 75-125 mv depending upon airflow compared to the stock settings in an effort to run a little leaner in closed loop. It seems that the error needs to be quite a bit below the theshold to have an effect on the integrator.
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Transmission: TH700 R4
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Re: No lean correction off idle... again!
It pegs the o2 at .05 mvolt. Nomatter how long it's held there the int won't richen.
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Re: No lean correction off idle... again!
Target AFR not equal to stoich?
Are you setting a code 44?
Code 44 or 45 locking the INT?
I don't know what else to suggest, but if it needs more fuel, give it more fuel.
I would still richen the MAF table or reduce the injector constant or raise the injector vbatt or low pulse width offsets to get more fuel to move the fuel trims slightly negative.
Are you setting a code 44?
Code 44 or 45 locking the INT?
I don't know what else to suggest, but if it needs more fuel, give it more fuel.
I would still richen the MAF table or reduce the injector constant or raise the injector vbatt or low pulse width offsets to get more fuel to move the fuel trims slightly negative.
Thread Starter
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Re: No lean correction off idle... again!
No problems there either. The last time I had this problem I had the lower o2 threshold set wrong, but that's not the case here. I have a hunch that the way I have my blm cell boundaries set up may be part of the problem. Is there a certain way it needs to be set to function properly?
Thread Starter
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From: right behind you
Car: '85 maro
Engine: In the works...
Transmission: TH700 R4
Axle/Gears: 3.73 posi
Re: No lean correction off idle... again!
Will disabling certain error codes (like fuel pump diag) have an effect like this? I still haven't found what's causing this.
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