8D idle ign. timing going up and down?
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Joined: Apr 2005
Posts: 18
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From: Helsinki, Finland
Car: Several, all with 8 cyl. Some bigger, some smaller
Engine: Ranging from L8 4,4 liter to over 9,2 liters full aluminum V config.
Transmission: Which one?
8D idle ign. timing going up and down?
Hello,
BLM staying at 128 and INT at 150, MAP shows steady KPAs at about 40, idle rpm @ 750. A/F stays pretty steady, std hydroller cam in a 350cid with 10,3 comp and a selfmade intake (similarities in all sizes to TPI) and 2x58mm throttlebody. Ported Vette 1989 aluminum heads with std valves. Not too big headers and twin 2,5" exhaust. Fuelpress at idle 55psi, 24lbs injectors. Not radical in any way.
Ign. at idle keeps jumping between 18 and 24 deg against TDC. Tried about everything I could think of... flattening fuel, ignition and just about every table there is one at a time. Can't seem to solve it. IAC stays steady as well.
Maybe PE MAP difference now at 1,25 KPA causing this? Or what the **** that is? Does not compute (me that is..)
TB way too big?
BTW,
what is the right table to control added fuel when engine is cold in TunerPro RT? Tried the table that controls crank fuel time vs. temp and the engine runs very rich when cold. No noticeable changes, maybe some. How big a changes are needed before it makes a real difference? 50%?
BLM staying at 128 and INT at 150, MAP shows steady KPAs at about 40, idle rpm @ 750. A/F stays pretty steady, std hydroller cam in a 350cid with 10,3 comp and a selfmade intake (similarities in all sizes to TPI) and 2x58mm throttlebody. Ported Vette 1989 aluminum heads with std valves. Not too big headers and twin 2,5" exhaust. Fuelpress at idle 55psi, 24lbs injectors. Not radical in any way.
Ign. at idle keeps jumping between 18 and 24 deg against TDC. Tried about everything I could think of... flattening fuel, ignition and just about every table there is one at a time. Can't seem to solve it. IAC stays steady as well.
Maybe PE MAP difference now at 1,25 KPA causing this? Or what the **** that is? Does not compute (me that is..)
TB way too big?
BTW,
what is the right table to control added fuel when engine is cold in TunerPro RT? Tried the table that controls crank fuel time vs. temp and the engine runs very rich when cold. No noticeable changes, maybe some. How big a changes are needed before it makes a real difference? 50%?
Last edited by JariV; Aug 4, 2006 at 05:19 AM.
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From: Chasing Electrons
Car: check
Engine: check
Transmission: check
The changing timing at idle is normal. It is intended to smooth the idle speed. Reducing the amount of timing change can help once an engine has been hot-rodded some. These two tables are the ones I change:
For the cold run fuel choke:
RBob.
Code:
;=======================================
; IDLE SA RETARD vs RPM
;
; TBL = SA * (256/90)
;=======================================
;--------------------------------------
; S.A. ; RPM
;--------------------------------------
L81EB: FCB 0 ; 0.0 0 RPM DIFF
FCB 28 ; 10 50
FCB 28 ; 10 100
FCB 28 ; 10 150
FCB 14 ; 10 200
;=======================================
; IDLE SA ADVANCE vs RPM ERROR
;
; TBL = 256/90
;=======================================
;--------------------------------------
; S.A. ; RPM ERROR
;--------------------------------------
L81F0: FCB 14 ; 5.0 0
FCB 14 ; 5.0 50
FCB 14 ; 5.0 100
FCB 14 ; 5.0 150
FCB 14 ; 5.0 200 Code:
;=======================================
; START UP ENRICH vs COOLANT TEMP
; *** CHOKE ***
;
;
; TBL = 2.56 * %CHG
;=======================================
;--------------------------------------
; %CHG ; Deg c
;--------------------------------------
L8431: FCB 243 ; -40.0
FCB 192 ; -28.0
FCB 154 ; -16.0
FCB 154 ; -4.0
FCB 128 ; 8.0
FCB 82 ; 20.0
FCB 82 ; 32.0
FCB 64 ; 44.0
FCB 49 ; 56.0
FCB 38 ; 68.0
FCB 38 ; 80.0
FCB 13 ; 92.0
FCB 13 ; 104.0
FCB 13 ; 116.0 Thread Starter
Junior Member
Joined: Apr 2005
Posts: 18
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From: Helsinki, Finland
Car: Several, all with 8 cyl. Some bigger, some smaller
Engine: Ranging from L8 4,4 liter to over 9,2 liters full aluminum V config.
Transmission: Which one?
Thanks.
I've tinkered with those just a bit. Maybe haven't been aggressive enough with the changes. I'll give it a try again.
I've tinkered with those just a bit. Maybe haven't been aggressive enough with the changes. I'll give it a try again.
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Joined: May 2004
Posts: 30
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From: Yukon, OK
Car: 95 Silverado
Engine: TBI 350
Transmission: 4L60E
Axle/Gears: 3.73 Detroit Truetrac
I have always wondered if that was normal. Mine does it too. It used to bug the heck out of me but I gave up on it. Does anybody know if there are any similar tables to adjust in $OD? dimented..... Hauln......?
Thanks
Brian
Thanks
Brian
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Joined: Jul 2003
Posts: 458
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From: Dallas
Originally Posted by BHall71
I have always wondered if that was normal. Mine does it too. It used to bug the heck out of me but I gave up on it. Does anybody know if there are any similar tables to adjust in $OD? dimented..... Hauln......?
Thanks
Brian
Thanks
Brian
Code:
;=============================================
; RPM OVERSPEED SPARK
;
;=============================================
;---------------------------------------------
; IDLE OVERSPEED SPARK RETARD Vs. RPM ERR
; (SPK RETARD Vs. RPM ERR)
; LINES = 7
;
; TBL = SPK ADV 256/90
;---------------------------------------------
ORG $44E6 ;
L44E6 FCB 96 ; 250 RPM UPPER TBL LMT
;
; Spk RPM ERR
;---------------------------------
L44E7 FCB 0 ; 0.0 0.0
L44E8 FCB 6 ; 2.1 12.5
L44E9 FCB 9 ; 3.2 25.0
L44EA FCB 11 ; 3.9 37.5
L44EB FCB 14 ; 4.9 50.0
L44EC FCB 14 ; 4.9 150.0
L44ED FCB 17 ; 6.0 150.0
;---------------------------------------------
;---------------------------------------------
; IDLE OVERSPEED SPARK ADJUST MULT Vs. MAP
;
; Dissassemby of BDWM, Lines = 9
;
; TBL = MULT * 2.56
;---------------------------------------------
ORG $44EE ;
L44EE FCB 128 ; 60 Kpa UPPER TBL LIMIT
;
; FACTOR Kpa MAP
;---------------------------------
L44EF FCB 255 ; 0.996 20
L44F0 FCB 255 ; 0.996 25
L44F1 FCB 255 ; 0.996 30
L44F2 FCB 255 ; 0.996 35
L44F3 FCB 244 ; 0.953 40
L44F4 FCB 244 ; 0.953 45
L44F5 FCB 232 ; 0.906 50
L44F6 FCB 175 ; 0.684 55
L44F7 FCB 128 ; 0.500 60
;---------------------------------------------
;---------------------------------------------
; UNDER SPEED IDLE SPK ADV Vs. RPM ERR
;
; Dissassemby of BDWM Lines= 7
;
; TBL = 2.844 * Deg Spk
;---------------------------------------------
ORG $44F8 ;
L44F8 FCB 96 ; 250 RPM UPPER TBL LMT
;
; Deg RPM
;---------------------------------
L44F9 FCB 0 ; O.0 0.0
L44FA FCB 3 ; 1.1 12.5
L44FB FCB 6 ; 2.1 25.0
L44FC FCB 9 ; 3.0 37.5
L44FD FCB 11 ; 3.9 50.0
L44FE FCB 9 ; 3.0 150.0
L44FF FCB 9 ; 3.0 150.0
;---------------------------------------------
;---------------------------------------------
; IDLE UNDER SPEED SPK ADV MULT Vs. MAP
;
; Dissassemby of BDWM Lines= 9
;
; TBL = MULT * 2.56
;---------------------------------------------
ORG $4500 ;
L4500 FCB 128 ; 60 Kpa UPPER TBL LIMIT
;
; FACTOR Kpa MAP
;---------------------------------
L4501 FCB 244 ; 0.953 20
L4502 FCB 232 ; 0.906 25
L4503 FCB 232 ; 0.906 30
L4504 FCB 232 ; 0.906 35
L4505 FCB 205 ; 0.800 40
L4506 FCB 166 ; 0.650 45
L4507 FCB 102 ; 0.400 50
L4508 FCB 32 ; 0.125 55
L4509 FCB 0 ; 0.000 60
;---------------------------------------------
;=============================================
; RPM DERIVITIVE SPK/FUEL CALIB'S
; SPARK CALIB'S, BDWM, MY 94 L05
; type $0D
;=============================================
L450A FCB 57 ; 20 Deg, IDLE SPK BIAS FOR TBL L4511 <-----<<
L450B FCB 11 ; 3.9 Deg, MAX IDLE SPK
L450C FCB 64 ; 1600 RPM
;
L450D FCB 221 ; FILT RPM COEF LIMIT
L450E FCB 101 ; FILT RPM COEF LIMIT
;
L450F FCB 116 ; MIN ADJ FM DERIVITIVE RPM/SPK/FUEL
L4510 FCB 141 ; LIMIT ADJ FM DERIVITIVE RPM/SPK/FUEL
;---------------------------------------------
;---------------------------------------------
; DERIVATIVE SPK/FUEL IDLE SA Vs. RPM RATIO
;
; VAL = DEG + K L450A (20 Deg spk bias)
;---------------------------------------------
ORG $4511 ; Deg RPM RATIO
;---------------------------------
L4511 FCB 50 ; -2.4 0.75000
L4512 FCB 51 ; -2.0 0.78125
L4513 FCB 52 ; -1.7 0.81250
L4514 FCB 53 ; -1.4 0.84375
L4515 FCB 54 ; -1.0 0.87500
L4516 FCB 55 ; -0.7 0.90625
L4517 FCB 56 ; -0.3 0.93750
L4518 FCB 57 ; 0.0 0.96875
L4519 FCB 57 ; 0.0 1.00000
L451A FCB 57 ; 0.0 1.03125
L451B FCB 58 ; 0.4 1.06250
L451C FCB 59 ; 0.7 1.09375
L451D FCB 60 ; 1.0 1.12500
L451E FCB 61 ; 1.4 1.15625
L451F FCB 62 ; 1.8 1.18750
L4520 FCB 63 ; 2.0 1.21875
L4521 FCB 64 ; 2.5 1.25000
;--------------------------------------------- EDIT: It would help if I posted the chde
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From: Moorestown, NJ
Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
Originally Posted by BHall71
I have always wondered if that was normal. Mine does it too. It used to bug the heck out of me but I gave up on it. Does anybody know if there are any similar tables to adjust in $OD? dimented..... Hauln......?
Thanks
Brian
Thanks
Brian
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From: Dallas, TX area
Car: 91 Formula WS6 (Black, T-Tops)
Engine: 383 MiniRam (529 HP, 519 TQ - DD2K)
Transmission: Built '97 T56, Pro 5.0, CF-DF
Axle/Gears: 4.11 posi Ford 9"
You might also check that you are not slipping in and out of "Idle Spark" mode, that could cause a big variance as well.....
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From: Browns Town
Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)
Engine: 406 Hyd Roller 236/242
Transmission: 700R4 HomeBrew, 2.4K stall
Axle/Gears: 3:73 Posi, 7.5 Soon to break
In the $8D there is also a threshold value that should be raised if you idle near 800 rpm. I was able to reduce the bouncing to only 3-4 degrees instead of the previous 8 that it was swinging.
This thread covered it: https://www.thirdgen.org/forums/diy-...k-advance.html
It didn't totally smooth out my idle but it did help a bit.
That and lowering the o2 thresholds for idle have made it not so rich and smelly to the point it is livable until I can concentrate on it more.
The in gear idle is good now, just unloaded in neutral it needs a little work.
This thread covered it: https://www.thirdgen.org/forums/diy-...k-advance.html
It didn't totally smooth out my idle but it did help a bit.
That and lowering the o2 thresholds for idle have made it not so rich and smelly to the point it is livable until I can concentrate on it more.
The in gear idle is good now, just unloaded in neutral it needs a little work.
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Joined: May 2004
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From: Yukon, OK
Car: 95 Silverado
Engine: TBI 350
Transmission: 4L60E
Axle/Gears: 3.73 Detroit Truetrac
Awesome! thanks for the replies! hope I am not jack-n the thread. Been messing with my idle target AFR and, I think, actually calibrating my narrow band o2, if such a thing is possible. At idle and cruise when the BLM's are happy my LC-1 is showing AFR's in a range from 13.8 to 14.6. Sometimes averaging as low as 14.0. A little rich for me. So I lowered the "o2 initial value" (48B4) to 377.60mv from the factory 450mv. Now my idle and cruise AFR's are actually averaging damn near 14.7 on the LC-1. Idle is much smoother and gas mileage is noticably better.
This weekend I hope to tweak the areas Tom showed above to get my idle even smoother.
Once again I gotta say thanks to all those responsible for the $OD hack and, of course, Hauln & dimented.
Brian
This weekend I hope to tweak the areas Tom showed above to get my idle even smoother.
Once again I gotta say thanks to all those responsible for the $OD hack and, of course, Hauln & dimented.
Brian
Thread Starter
Junior Member
Joined: Apr 2005
Posts: 18
Likes: 0
From: Helsinki, Finland
Car: Several, all with 8 cyl. Some bigger, some smaller
Engine: Ranging from L8 4,4 liter to over 9,2 liters full aluminum V config.
Transmission: Which one?
Hello again,
thanks to this thread got my idle from wandering up and down. Very steady now.
But another bug came up:
When starting the engine cold, it doesn't like to start, requires several times of trying.
When it eventually starts to run it immediately dies back, and this continues regardless of engine temps. It will start idling if I touch the gas right after it has fired up. But if I don't, it dies. Noticed that the ignition is right on at 19-22 before TDC and O2 mV:s are in 0,8-0,9 range. IAC though declines very fast. And OCCASIONALLY it is able to start idling but the rpm's go as low as 400 or so when it's about to stall and only after that it will reach target rpm which is 750.
Any ideas? What should I tune to correct this kinda thing?
thanks to this thread got my idle from wandering up and down. Very steady now.
But another bug came up:
When starting the engine cold, it doesn't like to start, requires several times of trying.
When it eventually starts to run it immediately dies back, and this continues regardless of engine temps. It will start idling if I touch the gas right after it has fired up. But if I don't, it dies. Noticed that the ignition is right on at 19-22 before TDC and O2 mV:s are in 0,8-0,9 range. IAC though declines very fast. And OCCASIONALLY it is able to start idling but the rpm's go as low as 400 or so when it's about to stall and only after that it will reach target rpm which is 750.
Any ideas? What should I tune to correct this kinda thing?
Thread Starter
Junior Member
Joined: Apr 2005
Posts: 18
Likes: 0
From: Helsinki, Finland
Car: Several, all with 8 cyl. Some bigger, some smaller
Engine: Ranging from L8 4,4 liter to over 9,2 liters full aluminum V config.
Transmission: Which one?
One more thing:
What kind of injector pulse widths are you getting from this computer (730, 8D) at WOT?
I'm wondering whether my 24lbs injectors are too small since my car does not go beyond 4000 rpm @ WOT and the upper Volumetric efficiency table is maxed out (values 100 all the way up from 3600). And BPW in that rpm is about 11ms.
When I pull the gaspedal (=TPS) of about 15% then it pulls like crazy. This happens with every gear.
And I noticed in TunerPro RT that the monitor scale ranges from 0.0 milliseconds to 250 ms. And my maximum value at best is 11. How do I up the pulse width in this case???
Otherwize than WOT at rpms over 3600 my engine performs very well.
Any ideas?
What kind of injector pulse widths are you getting from this computer (730, 8D) at WOT?
I'm wondering whether my 24lbs injectors are too small since my car does not go beyond 4000 rpm @ WOT and the upper Volumetric efficiency table is maxed out (values 100 all the way up from 3600). And BPW in that rpm is about 11ms.
When I pull the gaspedal (=TPS) of about 15% then it pulls like crazy. This happens with every gear.
And I noticed in TunerPro RT that the monitor scale ranges from 0.0 milliseconds to 250 ms. And my maximum value at best is 11. How do I up the pulse width in this case???
Otherwize than WOT at rpms over 3600 my engine performs very well.
Any ideas?
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