I really could use some advice....
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I really could use some advice....
I have been having an issue with what seem to be a lean miss in the 2800-3800 rpm range under part throttle.
I adjusted the blm to 128 (or at least close).
Still have the lean miss.
I finally got my WB going and datalogging.
When in this area the BLM / INT are near 128'ish, however, the
WB is showing lean.
I have no clue what to do, I am stumped...
I have attached part of my data log in this area.
Could someone take a look at it and give me some suggestions
Thanks
Tom
WB Scan.csv
I adjusted the blm to 128 (or at least close).
Still have the lean miss.
I finally got my WB going and datalogging.
When in this area the BLM / INT are near 128'ish, however, the
WB is showing lean.
I have no clue what to do, I am stumped...
I have attached part of my data log in this area.
Could someone take a look at it and give me some suggestions
Thanks
Tom
WB Scan.csv
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From: In reality
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Try taking a bunch of timing out.
The goal is running the least amount of timing consistant with max performance.
While a K/S can somewhat reliably detect detonation, it can miss pre-ignition. Running lots of timing, real lean puts alot of heat into the chamber, and makes it real prone to pre-ignition, if not just poor combustion events.
The goal is running the least amount of timing consistant with max performance.
While a K/S can somewhat reliably detect detonation, it can miss pre-ignition. Running lots of timing, real lean puts alot of heat into the chamber, and makes it real prone to pre-ignition, if not just poor combustion events.
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Originally posted by RBob
A silicon poisoned O2 sensor will cause this. Is this a GM O2 sensor?
RBob.
A silicon poisoned O2 sensor will cause this. Is this a GM O2 sensor?
RBob.
I guess I'll have to get another one.
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From: Grand Island, NY
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Originally posted by Grumpy
Try taking a bunch of timing out.
The goal is running the least amount of timing consistant with max performance.
While a K/S can somewhat reliably detect detonation, it can miss pre-ignition. Running lots of timing, real lean puts alot of heat into the chamber, and makes it real prone to pre-ignition, if not just poor combustion events.
Try taking a bunch of timing out.
The goal is running the least amount of timing consistant with max performance.
While a K/S can somewhat reliably detect detonation, it can miss pre-ignition. Running lots of timing, real lean puts alot of heat into the chamber, and makes it real prone to pre-ignition, if not just poor combustion events.
The thing that puzzled me was the computer BLMs were near 128 but the WB was lean.
I'll mess with the spark also.
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Well, New O2 sensor and lowered spark.
(On a side note bought the original O2 sensor from GM had gm sticker and box. The thing was a BOSH sensor! never noticed till I removed it to put the new one in. Couldn't find anything but a Bosh so that is what I had to use)
Do not necessarily notice a lean miss, however, still shows lean on wb and 133 ish in blms.
Shouldn't the computer be compensating for the lean condition and be adding fuel to bring it back to 14.7?
Some times it still is in 16 range.
Here is another short scan
WB2.CSV
Thanks again for any help.
Tom
(On a side note bought the original O2 sensor from GM had gm sticker and box. The thing was a BOSH sensor! never noticed till I removed it to put the new one in. Couldn't find anything but a Bosh so that is what I had to use)
Do not necessarily notice a lean miss, however, still shows lean on wb and 133 ish in blms.
Shouldn't the computer be compensating for the lean condition and be adding fuel to bring it back to 14.7?
Some times it still is in 16 range.
Here is another short scan
WB2.CSV
Thanks again for any help.
Tom
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From: In reality
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Originally posted by novass
Can you cut and past your timing, and VE tables?.
38+d at 70K/Pa sounds really excessive to me.
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From: Grand Island, NY
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Originally posted by Grumpy
How big of combustion chambers are you running?.
Can you cut and past your timing, and VE tables?.
38+d at 70K/Pa sounds really excessive to me.
How big of combustion chambers are you running?.
Can you cut and past your timing, and VE tables?.
38+d at 70K/Pa sounds really excessive to me.
I have port and polished 58cc World Torquer cast iron heads, stock pistons in the 305.
You still think I have too much spark? Even though these are the stock tables? I am keeping an open mind.... (Would this be causing the lean condition I see on the wide band?)
I REALLY appreciate the help.
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Do not necessarily notice a lean miss, however, still shows lean on wb and 133 ish in blms.
Shouldn't the computer be compensating for the lean condition and be adding fuel to bring it back to 14.7?
Shouldn't the computer be compensating for the lean condition and be adding fuel to bring it back to 14.7?
on a sidenote, do you think lean condition occurs when you are moving the gas pedal? Kind of a situation for AE?
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a miss fire will show up as lean on both a WB02 and the stock o2 sensor and in the ECM fuel trim. when excessive amount of O2 goe past the sensor it thinks lean. Missfire = Lots of oxygen no fuel burned.
O2 sensor is a negative coefficient of oxgen content.
0 millvolts = pure air ( from atmosphere) no fuel
999 millivolts indacte lack of oxygen or to much fuel
So with this in mind and having known large cams to cuase false lean conidiotns due to valve overlap i could say that turn off the stock 02 set ECM fo OL by changing the min temp for CL operation to something like 150C and just tune the thing till it runs good at a reasonable AFR i do this alot BTW
O2 sensor is a negative coefficient of oxgen content.
0 millvolts = pure air ( from atmosphere) no fuel
999 millivolts indacte lack of oxygen or to much fuel
So with this in mind and having known large cams to cuase false lean conidiotns due to valve overlap i could say that turn off the stock 02 set ECM fo OL by changing the min temp for CL operation to something like 150C and just tune the thing till it runs good at a reasonable AFR i do this alot BTW
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From: Grand Island, NY
Car: 1990 Formula
Engine: 305 TPI
Transmission: WC T5
Originally posted by 11sORbust
on a sidenote, do you think lean condition occurs when you are moving the gas pedal?
on a sidenote, do you think lean condition occurs when you are moving the gas pedal?
The pedal was consistantly applied.
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Car: 1990 Formula
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Originally posted by funstick
a miss fire will show up as lean on both a WB02 and the stock o2 sensor and in the ECM fuel trim. when excessive amount of O2 goe past the sensor it thinks lean. Missfire = Lots of oxygen no fuel burned.
O2 sensor is a negative coefficient of oxgen content.
0 millvolts = pure air ( from atmosphere) no fuel
999 millivolts indacte lack of oxygen or to much fuel
So with this in mind and having known large cams to cuase false lean conidiotns due to valve overlap i could say that turn off the stock 02 set ECM fo OL by changing the min temp for CL operation to something like 150C and just tune the thing till it runs good at a reasonable AFR i do this alot BTW
a miss fire will show up as lean on both a WB02 and the stock o2 sensor and in the ECM fuel trim. when excessive amount of O2 goe past the sensor it thinks lean. Missfire = Lots of oxygen no fuel burned.
O2 sensor is a negative coefficient of oxgen content.
0 millvolts = pure air ( from atmosphere) no fuel
999 millivolts indacte lack of oxygen or to much fuel
So with this in mind and having known large cams to cuase false lean conidiotns due to valve overlap i could say that turn off the stock 02 set ECM fo OL by changing the min temp for CL operation to something like 150C and just tune the thing till it runs good at a reasonable AFR i do this alot BTW
So from what I you are suggesting is that possibly my ignition system my be leading to some of this?
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From: Grand Island, NY
Car: 1990 Formula
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Originally posted by contactpatch
novass,,,
where did those fuel and spark tables,
come from?
contact
novass,,,
where did those fuel and spark tables,
come from?
contact
VE tables are mine tuned via blm feedback
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From: Chasing Electrons
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I took the second log posted and graphed the O2 value (divided by 100) and the WB value together. They actually don't look too bad. A good portion of the graph tracks right along averaging a 14.7:1 AFR.
Two things come to mind: what are the O2 window values (calibration points) programmed into the ECM. And, how well is the ECM reading and translating the WB AFR output.
Connecting a WB to an ECM and retaining accurate readings can be tricky. Depending upon the WB output voltage range only a few millivolts can change the displayed AFR.
That and the ECM is only an 8-bit ADC. This gives 20mV per bit.
RBob.
Two things come to mind: what are the O2 window values (calibration points) programmed into the ECM. And, how well is the ECM reading and translating the WB AFR output.
Connecting a WB to an ECM and retaining accurate readings can be tricky. Depending upon the WB output voltage range only a few millivolts can change the displayed AFR.
That and the ECM is only an 8-bit ADC. This gives 20mV per bit.
RBob.
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Originally posted by RBob
Two things come to mind: what are the O2 window values (calibration points) programmed into the ECM. And, how well is the ECM reading and translating the WB AFR output.
Two things come to mind: what are the O2 window values (calibration points) programmed into the ECM. And, how well is the ECM reading and translating the WB AFR output.
And how might i use these to change where the ecm sees a "proper" o2/blm amount.
I will check the output of the wb with my digital volt meter and compare it to the value that the ecm is outputting.
Thanks for you help RBob!
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From: Chasing Electrons
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Originally posted by novass
Where would I determine the 02 window values in the super 8dm1.ecu?
And how might i use these to change where the ecm sees a "proper" o2/blm amount.
I will check the output of the wb with my digital volt meter and compare it to the value that the ecm is outputting.
Thanks for you help RBob!
Where would I determine the 02 window values in the super 8dm1.ecu?
And how might i use these to change where the ecm sees a "proper" o2/blm amount.
I will check the output of the wb with my digital volt meter and compare it to the value that the ecm is outputting.
Thanks for you help RBob!
{edit: table info deleted due to being invalid. See my next post a little further down}
RBob.
Last edited by RBob; Jun 23, 2004 at 06:51 PM.
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What does each table do?
UPPER ZERO ERROR REF FOR SLOW O2 R/L vs MAP
for this table. is this the point that the ecm toggles around that is concidered stoich (BLM 128)?
FAST O2 R/L THRESHOLD vs MAP
How is this table different? What is meant by fast/slow?
053 mvdc, DIFF TO MAKE R/L WINDOW (FAST O2)
Is This is the amount of millivolts that can be +- from that table value to be concidered stoich?
Just trying to lean what each section means.
Thanks
Tom
UPPER ZERO ERROR REF FOR SLOW O2 R/L vs MAP
for this table. is this the point that the ecm toggles around that is concidered stoich (BLM 128)?
FAST O2 R/L THRESHOLD vs MAP
How is this table different? What is meant by fast/slow?
053 mvdc, DIFF TO MAKE R/L WINDOW (FAST O2)
Is This is the amount of millivolts that can be +- from that table value to be concidered stoich?
Just trying to lean what each section means.
Thanks
Tom
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Originally posted by novass
I will check the output of the wb with my digital volt meter and compare it to the value that the ecm is outputting.
I will check the output of the wb with my digital volt meter and compare it to the value that the ecm is outputting.
But it is still lean.
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did some open loop runs. Holy crap was there a difference in the 2500-4000 rpm range!!
The front of the car actually lifted noticably and it screamed thru that rpm range where before it would seem like it would take "forever" to get thru the range.
However, I would still like feed back on changing the O2 range so that I can put the computer back into the loop.
Does any one becides Rbob know?
The front of the car actually lifted noticably and it screamed thru that rpm range where before it would seem like it would take "forever" to get thru the range.
However, I would still like feed back on changing the O2 range so that I can put the computer back into the loop.
Does any one becides Rbob know?
Last edited by novass; Jun 23, 2004 at 08:31 AM.
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From: Chasing Electrons
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$8D O2 window tables
Just spent some time figuring out the $8D mask O2 window tables. The hac has a few errors in this regard. I edited my previous reply on this topic.
Here are some constants and tables:
So what do they do? The fast O2 table at L84B4 is used to discover the direction the O2 sensor is moving, and hence the AFR. The value at L849C is used to create a small window. The term at L849C is both subtracted and added to this table in order to create upper and lower boundries.
This FAST O2 R/L table thresholds are used to increment the x-cnts, reset proportional gains duration and for AFR direcction detection.
The oter two tables (UPPER and LOWER SLOW O2) form the boundries that the O2 sensor must cross into in order to hold the INTegrator at a constant value. The O2 ONLY needs to travel within either the upper or lower boundry. It does not need to cross both.
The term at L849D is subtracted from all of the three table values. According to the code/comments this occures whenever the air pump air is being diverted to the atmosphere. I do not know if this is exactly true or not.
Notice that the FAST R/L table values typically sits inbetween the two SLOW O2 tables.
The table at L84F6 is also used to adjust the lookups from the three O2 tables listed above (it is subtracted).
RBob.
Here are some constants and tables:
Code:
L849C: FCB 12 ; 53 mvdc, DIFF TO MAKE R/L WINDOW (FAST O2) ; L849D: FCB 23 ; 100 mvdc, DIFF R/L WHEN AIR DIVERTED ;======================================= ; UPPER THRESHOLD FOR SLOW O2 R/L vs MAP ; ; ; TBL = O2 VOLTS * 266 ;======================================= ;-------------------------------------- ; O2 ; Kpa MAP ;-------------------------------------- L84A2: FCB 140 ; 20 FCB 148 ; 30 FCB 152 ; 40 FCB 132 ; 50 FCB 132 ; 60 FCB 132 ; 70 FCB 132 ; 80 FCB 132 ; 90 FCB 132 ; 100 ;======================================= ; LOWER THRESHOLD FOR SLOW O2 R/L vs MAP ; ; ; TBL = O2 VOLTS * 266 ;======================================= ;-------------------------------------- ; O2 ; Kpa MAP ;-------------------------------------- L84AB: FCB 120 ; 20 FCB 128 ; 30 FCB 132 ; 40 FCB 112 ; 50 FCB 112 ; 60 FCB 112 ; 70 FCB 112 ; 80 FCB 112 ; 90 FCB 112 ; 100 ;======================================= ; FAST O2 R/L THRESHOLD vs MAP ; ; +- L859C ; ; TBL = O2 VOLTS * 266 ;======================================= ;-------------------------------------- ; O2 ; MAP KPa ;-------------------------------------- L84B4: FCB 130 ; 20 FCB 138 ; 30 FCB 142 ; 40 FCB 122 ; 50 FCB 122 ; 60 FCB 122 ; 70 FCB 122 ; 80 FCB 122 ; 90 FCB 122 ; 100
This FAST O2 R/L table thresholds are used to increment the x-cnts, reset proportional gains duration and for AFR direcction detection.
The oter two tables (UPPER and LOWER SLOW O2) form the boundries that the O2 sensor must cross into in order to hold the INTegrator at a constant value. The O2 ONLY needs to travel within either the upper or lower boundry. It does not need to cross both.
The term at L849D is subtracted from all of the three table values. According to the code/comments this occures whenever the air pump air is being diverted to the atmosphere. I do not know if this is exactly true or not.
Notice that the FAST R/L table values typically sits inbetween the two SLOW O2 tables.
The table at L84F6 is also used to adjust the lookups from the three O2 tables listed above (it is subtracted).
RBob.
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:hail:
You are awsome!!
Thank you very much for the informative response!
It is going to take me a bit to digest it.
I really want to get this to work so that I can get the blms to 128 around the correct readings I am getting from the wb.
Thanks again.
I will post how my progress goes.
You are awsome!!
Thank you very much for the informative response!
It is going to take me a bit to digest it.
I really want to get this to work so that I can get the blms to 128 around the correct readings I am getting from the wb.
Thanks again.
I will post how my progress goes.
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Just would like to check my thought process.
1st of all I plan on tuning all of my ve with wb to get as close to possible to 14.7 under non pe
Then use the above tables to bring the stock sensor to 128 blms to correspond with the ve tables I have set using the wb.
Now for the tables.
as the o2 volts go up it is getting leaner... correct?
so my thought is I need to shift the values in the tables down, since I was lean using the stock o2
My plan was to take all three tables and where I was experiencing lean readings those map readings lower the numbers in all three tables. Keeping all the fast 02 in the middle.
so say:
At 40 Kpa
Upper threshold to say 150
Lower threshold to say 130
And Fast o2 to say 140
Would my thinking be correct?
Feed back would be appreciated.
Thanks
Tom
1st of all I plan on tuning all of my ve with wb to get as close to possible to 14.7 under non pe
Then use the above tables to bring the stock sensor to 128 blms to correspond with the ve tables I have set using the wb.
Now for the tables.
as the o2 volts go up it is getting leaner... correct?
so my thought is I need to shift the values in the tables down, since I was lean using the stock o2
My plan was to take all three tables and where I was experiencing lean readings those map readings lower the numbers in all three tables. Keeping all the fast 02 in the middle.
so say:
At 40 Kpa
Upper threshold to say 150
Lower threshold to say 130
And Fast o2 to say 140
Would my thinking be correct?
Feed back would be appreciated.
Thanks
Tom
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From: Chasing Electrons
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A NB O2 is richer as the voltage goes up. So you want to raise the O2 table terms.
If the engine is running w/o the air pump be sure to set the term at L849D to 0 and to set the air pump divert enable temperature to 151C (At L839A). Double check the data logs to be sure that it is always in divert mode.
150 / 226 = 664 mV, which is on the rich side of 450 mV.
130 / 226 = 575 mV
So those terms seem to be a good place to start.
RBob.
If the engine is running w/o the air pump be sure to set the term at L849D to 0 and to set the air pump divert enable temperature to 151C (At L839A). Double check the data logs to be sure that it is always in divert mode.
150 / 226 = 664 mV, which is on the rich side of 450 mV.
130 / 226 = 575 mV
So those terms seem to be a good place to start.
RBob.
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Well here is what I did.
I tuned the car with the WB in open loop so all of the cruse/part throttle/no pe full throttle areas were darn near 14.7.
Use Traxon's AFR Tuner to get my PE areas about 12.7.
The car runs great in open loop!
now I tried to adjust to O2 swings using the areas above...
would not work out for me, here is why.
During alot of my part throttle areas I was in 30 and 40 MAP, even in the area I was originally having problems in the 3-4000 rpm range at part throttle.
So here was the delema, the areas that were low in the rpm range were "seen" by the stock NB as right on BLM 128 and the areas in the higher RPM Ranges was seen as lean. Here is the Kicker both were in the same MAP range so when I changed the swing points for the O2 in the 30 40 ranges it thru off the lower rpm areas when the upper areas began to get closer.
So..... It is running so good in open loop, I am going to stick with it.
I tuned the car with the WB in open loop so all of the cruse/part throttle/no pe full throttle areas were darn near 14.7.
Use Traxon's AFR Tuner to get my PE areas about 12.7.
The car runs great in open loop!
now I tried to adjust to O2 swings using the areas above...
would not work out for me, here is why.
During alot of my part throttle areas I was in 30 and 40 MAP, even in the area I was originally having problems in the 3-4000 rpm range at part throttle.
So here was the delema, the areas that were low in the rpm range were "seen" by the stock NB as right on BLM 128 and the areas in the higher RPM Ranges was seen as lean. Here is the Kicker both were in the same MAP range so when I changed the swing points for the O2 in the 30 40 ranges it thru off the lower rpm areas when the upper areas began to get closer.
So..... It is running so good in open loop, I am going to stick with it.
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What about weather condition changes and water temp changes?
How does the WB datalog look for the above condition changes when running full time open loop?
How does the WB datalog look for the above condition changes when running full time open loop?
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I blieve that even in open loop the tables that deal with coolant temp and MAT temp are in use.
I only drive my car in nice weather, my data logs of the WB have been pretty consistant.
Maybe an "expert" could chime in on the coolant and MAT stuff, either saying ya or nay.
I only drive my car in nice weather, my data logs of the WB have been pretty consistant.
Maybe an "expert" could chime in on the coolant and MAT stuff, either saying ya or nay.
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