Spark Advance Dip to -10 degrees
Thread Starter
Launching!
Joined: Nov 2002
Posts: 261
Likes: 0
From: Freehold, NJ
Spark Advance Dip to -10 degrees I saw this in one of my WOT log files.. Can someone explain why my spark advance went all the way down to -10degrees and there was no KR or anything out of the ordinary?
The entire logfile can be viewed here
Thanks.
The entire logfile can be viewed here
Thanks.
I looked at your log and can not see any reason that one entry had a -10 in it. I think I would remove that row of data and call it bad data. What version autotap are you using? Maybe it is a problem with the logging software.
Are you running a little rich or what?
BowlingSS
Are you running a little rich or what?
BowlingSS
TECH Resident
Joined: Jan 2002
Posts: 754
Likes: 0
From: USA
IMHO your testing methods will not gain you the best information.
The scanner your using is only requesting 10 frames or less per second
the test recording was less then 2 minutes. LTFTs are only reacted on by PCM once every 10 minutes and O2s only reacted on once a second so your seeing very little reaction time of PCM for that short record period.
Your missing other important PIDs.
The PCM is running in the low octane table and though in that short run the knock was only 2 degrees the PE timing avg was only 15 degrees which is low octane timing
No matter what cyberspace says there is a BAD gas bit and there has to be for a car can get a bad tank of gas or the owner used too low of an octane and PCM then protects the powertrain by tripping the bad gas bit and even though your not getting lots of knock now is because PCM is using low octane table to have stopped most of the knock and stays there until there has been an increase of 20% more fuel then the amount in tank on last vaild startup.
Its clear with injector duty cycle as high as 85% at only 5,000 RPMs while pushing as much as 42 lbs/min airflow that the engine has run too lean.
-10 degrees is valid since that is what the stock retard timing lookup table is set to.
Being the outside air temps was only about 40 degrees,
in hotter weather the AFR will get worse for PE or WOT conditions.
Not knowing the tune, knock functions could have been mistuned and thus would not report much knock.
Without other PIDs or DTCs being recorded its hard to tell if it is fact going to PE mode.
The scanner your using is only requesting 10 frames or less per second
the test recording was less then 2 minutes. LTFTs are only reacted on by PCM once every 10 minutes and O2s only reacted on once a second so your seeing very little reaction time of PCM for that short record period.
Your missing other important PIDs.
The PCM is running in the low octane table and though in that short run the knock was only 2 degrees the PE timing avg was only 15 degrees which is low octane timing
No matter what cyberspace says there is a BAD gas bit and there has to be for a car can get a bad tank of gas or the owner used too low of an octane and PCM then protects the powertrain by tripping the bad gas bit and even though your not getting lots of knock now is because PCM is using low octane table to have stopped most of the knock and stays there until there has been an increase of 20% more fuel then the amount in tank on last vaild startup.
Its clear with injector duty cycle as high as 85% at only 5,000 RPMs while pushing as much as 42 lbs/min airflow that the engine has run too lean.
-10 degrees is valid since that is what the stock retard timing lookup table is set to.
Being the outside air temps was only about 40 degrees,
in hotter weather the AFR will get worse for PE or WOT conditions.
Not knowing the tune, knock functions could have been mistuned and thus would not report much knock.
Without other PIDs or DTCs being recorded its hard to tell if it is fact going to PE mode.
On The Tree
Joined: Oct 2003
Posts: 175
Likes: 0
Originally Posted by Team ZR-1
No matter what cyberspace says there is a BAD gas bit and there has to be for a car can get a bad tank of gas or the owner used too low of an octane and PCM then protects the powertrain by tripping the bad gas bit and even though your not getting lots of knock now is because PCM is using low octane table to have stopped most of the knock and stays there until there has been an increase of 20% more fuel then the amount in tank on last vaild startup.
High/Low Octane Tables
And This Link
It all looks pretty convincing to me that the "BAD GAS BIT" is a myth.
Thread Starter
Launching!
Joined: Nov 2002
Posts: 261
Likes: 0
From: Freehold, NJ
Crap! I just realized what I did.. 
I screwed up on the graph.. I set autofilter on excel and filtered on 100% TP. I forgot that I did more then one WOT run. That's why the frames aren't all in sequence.. Sorry about that..
Still.. I dropped to -10 degrees on frame 169..
Car is stock.. the only mod is a lid. The software was EFILiveV6.
There are no DTC's.
I screwed up on the graph.. I set autofilter on excel and filtered on 100% TP. I forgot that I did more then one WOT run. That's why the frames aren't all in sequence.. Sorry about that..
Still.. I dropped to -10 degrees on frame 169..
Car is stock.. the only mod is a lid. The software was EFILiveV6.
There are no DTC's.
TECH Resident
Joined: Jan 2002
Posts: 754
Likes: 0
From: USA
YES
There is not a low octane table for nothing and anyone knows a bad tank of gas or wrong type of gas used happens and that increased knock to be dealt with.
Maybe this way American cars such as the Corvette have the function and cars "down under" do not ?
Its been proven several times that people at the drag strip trip several knocks in a row, and spend the rest of the day with low timing UNTIL more fuel is added and the Bad Gas bit is mentioned in GM documents.
I've tested this on my '99 C5 and the function is there.
There is not a low octane table for nothing and anyone knows a bad tank of gas or wrong type of gas used happens and that increased knock to be dealt with.
Maybe this way American cars such as the Corvette have the function and cars "down under" do not ?
Its been proven several times that people at the drag strip trip several knocks in a row, and spend the rest of the day with low timing UNTIL more fuel is added and the Bad Gas bit is mentioned in GM documents.
I've tested this on my '99 C5 and the function is there.
Originally Posted by Fetumpsh
Are you suggesting the guys at EFILive got it wrong when it comes to the
High/Low Octane Tables
And This Link
It all looks pretty convincing to me that the "BAD GAS BIT" is a myth.
High/Low Octane Tables
And This Link
It all looks pretty convincing to me that the "BAD GAS BIT" is a myth.
Trending Topics
On The Tree
Joined: Oct 2003
Posts: 175
Likes: 0
Originally Posted by 2002WS6_MN6
Crap! I just realized what I did..
I screwed up on the graph.. I set autofilter on excel and filtered on 100% TP. I forgot that I did more then one WOT run. That's why the frames aren't all in sequence.. Sorry about that..
Still.. I dropped to -10 degrees on frame 169..
Car is stock.. the only mod is a lid. The software was EFILiveV6.
There are no DTC's.
I screwed up on the graph.. I set autofilter on excel and filtered on 100% TP. I forgot that I did more then one WOT run. That's why the frames aren't all in sequence.. Sorry about that..
Still.. I dropped to -10 degrees on frame 169..
Car is stock.. the only mod is a lid. The software was EFILiveV6.
There are no DTC's.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo On The Tree
Joined: Oct 2003
Posts: 175
Likes: 0
Originally Posted by Team ZR-1
YES
Maybe this way American cars such as the Corvette have the function and cars "down under" do not ?
Maybe this way American cars such as the Corvette have the function and cars "down under" do not ?
The "down under' cars have adaptive knock (I have logged it)
They have no Fuel Tank level sensor to the PCM.
On The Tree
Joined: Oct 2003
Posts: 175
Likes: 0
Originally Posted by Team ZR-1
I've tested this on my '99 C5 and the function is there.
You said you have tested this on your C5, just wondering what PID you used for that (to show it was running in one or the other table, which I still don't believe it does), or how you actually determined the car was running exclusively in the Low Octane Table.
The log files shown on the EFILive site are VERY convincing to my suggestion that the PCM simply doesn't switch between one table or the other, nor does filling the tank up with 'x' amount of fuel reset said bit, and given one of those graphs was from a Camaro (emarkay) is on this list, it's not a 'down under' thing as you suggested.......
This is how Torque Management works. It pulls spark
all the way back until the shift has cycled. If you
see this coincident with (or within a few frames of)
shift then this is totally normal for a car that hasn't
had TM eliminated.
all the way back until the shift has cycled. If you
see this coincident with (or within a few frames of)
shift then this is totally normal for a car that hasn't
had TM eliminated.
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
Funny, I do recall a certain "expert" being laughed off a few forums already due to a lack of substiantiated facts and a general "used car salesman" type of attitude.
To qoute a famous philosopher of the last century: "Well, whatever, neveremind..." C. Kobain.
****
As for torque management, here's a good link...
http://www.efilive.com/forum/viewtopic.php?t=314
As for your data, MN6, I won't look at anything but the source - transcribed data is as good as no data! Feel free to email me the original logs to emarkay@email.com, along with some details about car, mileage, maintenance, and the like.
To qoute a famous philosopher of the last century: "Well, whatever, neveremind..." C. Kobain.
****
As for torque management, here's a good link...
http://www.efilive.com/forum/viewtopic.php?t=314
As for your data, MN6, I won't look at anything but the source - transcribed data is as good as no data! Feel free to email me the original logs to emarkay@email.com, along with some details about car, mileage, maintenance, and the like.
Last edited by emarkay; Jan 25, 2004 at 02:38 PM. Reason: spelling
TECH Resident
Joined: Jan 2002
Posts: 754
Likes: 0
From: USA
It's clear 2 of you need to learn the basics of what GM does in the PCM.
Anyone knows on normal knock the PCM draws 4 degees of timing at a time till knock decays and then raises timing 2 degrees at a time to return from a knock.
Anyone with brains knows if the wrong or bad gas is in the tank you do NOT run with higher timing UNTIL at least that tank has been deluted by at least 20% more good fuel added.
I guess GM put these functions/PIDs in for nothing but clearly if using a low grade PCM scanner you would not ever see these.
As to proof start reading GM training and tech manuals but until then I would not suggest you do any tuning until you learn how the adaptive strategy functions
Anyone knows on normal knock the PCM draws 4 degees of timing at a time till knock decays and then raises timing 2 degrees at a time to return from a knock.
Anyone with brains knows if the wrong or bad gas is in the tank you do NOT run with higher timing UNTIL at least that tank has been deluted by at least 20% more good fuel added.
I guess GM put these functions/PIDs in for nothing but clearly if using a low grade PCM scanner you would not ever see these.
As to proof start reading GM training and tech manuals but until then I would not suggest you do any tuning until you learn how the adaptive strategy functions
On The Tree
Joined: Oct 2003
Posts: 175
Likes: 0
Originally Posted by Team ZR-1
It's clear 2 of you need to learn the basics of what GM does in the PCM.
Anyone knows on normal knock the PCM draws 4 degees of timing at a time till knock decays and then raises timing 2 degrees at a time to return from a knock.
Anyone knows on normal knock the PCM draws 4 degees of timing at a time till knock decays and then raises timing 2 degrees at a time to return from a knock.
However, you have said the PCM pulls 4 degrees when 'normal' knock is detected, Mmmm, my scanner show values much less than that when knock is deteted, so please teach me the basics again....
Originally Posted by Team ZR-1
Anyone with brains knows if the wrong or bad gas is in the tank you do NOT run with higher timing UNTIL at least that tank has been deluted by at least 20% more good fuel added.
Originally Posted by Team ZR-1
I guess GM put these functions/PIDs in for nothing but clearly if using a low grade PCM scanner you would not ever see these.
How many Ease users on this forum have logged adaptive spark at work, c'mon, between the three of you, you must have.
Originally Posted by Team ZR-1
As to proof start reading GM training and tech manuals but until then I would not suggest you do any tuning until you learn how the adaptive strategy functions
Show me you "Bad Gas Bit" in Ease??.
Teching In
Joined: Dec 2001
Posts: 387
Likes: 0
From: Southern IN, USA
Deluted - Isn't that what the Italians do to bad musicians?
However, if you look, there is "weasel wiggle" here - by adding some higher octane fuel to a partial tank of lower octane fuel you are raising the average R+M to the point where the adaptive spark no longer keeps retarding the baseline. Of course, there is no sensor, it's just increasing average octane by adding higher octane fuel - duh!
Did ANYONE see my posts on"PISSGAS"?
http://www.efilive.com/forum/viewtopic.php?t=298
If anyone would like the 4 complete log files (the long baseline, the adding of 86 octane and a long run, to the adding of 94 and a long run, and the conclusion where adaptive spark returns to 100%) just let me know and I can upload them, and you can see for yourself.
Still no "Bad Gas Bit", eh?
BTW, what GM manual are you sourcing with "knock too long" PID - and for what application, model year and PCM calibration #?
:insert animated used car dealer smiley here:
"Have I got a deal for you! I have this little creampuff here, just used by a little old lady who only went to bingo with it - it was last Revised on May 03, 2002 and for just Nine Ninety Five it's a steal - now, if you want a body and a chassis, too, that'll be an extra Five Ninety Five, but if you pay me now in cash, I'll throw in a free set of floor mats and this handy ice scraper, too! Hurry, Hurry, Hurry!"
However, if you look, there is "weasel wiggle" here - by adding some higher octane fuel to a partial tank of lower octane fuel you are raising the average R+M to the point where the adaptive spark no longer keeps retarding the baseline. Of course, there is no sensor, it's just increasing average octane by adding higher octane fuel - duh!
Did ANYONE see my posts on"PISSGAS"?
http://www.efilive.com/forum/viewtopic.php?t=298
If anyone would like the 4 complete log files (the long baseline, the adding of 86 octane and a long run, to the adding of 94 and a long run, and the conclusion where adaptive spark returns to 100%) just let me know and I can upload them, and you can see for yourself.
Still no "Bad Gas Bit", eh?
BTW, what GM manual are you sourcing with "knock too long" PID - and for what application, model year and PCM calibration #?
:insert animated used car dealer smiley here:
"Have I got a deal for you! I have this little creampuff here, just used by a little old lady who only went to bingo with it - it was last Revised on May 03, 2002 and for just Nine Ninety Five it's a steal - now, if you want a body and a chassis, too, that'll be an extra Five Ninety Five, but if you pay me now in cash, I'll throw in a free set of floor mats and this handy ice scraper, too! Hurry, Hurry, Hurry!"
Last edited by emarkay; Jan 26, 2004 at 09:35 AM. Reason: spelling
