DIY PROMDo It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I'm having an issue with cold spark advance. I am not sure why it is setting the timing back so far when it is cold. It is giving the car fits.
First off, I'm running a 230/236 cam on a 110lsa.
I have idle spark advance set to 29* along with the main spark advance table. This is where it seems to idle best when warm and pull the most vacuum.
Then at 45* This happens. Spark jumps back up to 25*, Int goes back in line.
RPM: 1100
MAP:50
Spark Advance: 25*
BLM: 124
INT: 130
Then by 65*C Spark advance creeped back up to the commanded 29*
RPM:950
MAP:59
Spark advance: 29
BLM 125
INT 128
Any idea's? It doesnt make sense.
Here is the coolant correction table. It is the stock table for S_AUJP the bias is set at 20.04* so no where can I find where it is taking out 15*. Looks like its taking out 5* near the 40*c area but where is the other 10* coming from?
Spark Advance Cold Disable: 44.75*C so that is right where it spikes from 13* to 25* instantly
The coolant correction bias is subtracted from this table to give you the advance/retard amount correct?
Am I missing another table or value or something??????
Thanks
__________________ 1987 Trans Am GTA, Turbocharged 357ci 470rwhp/565rwtq 11.12@124mph
Last edited by mike1986fyrbird; 03-08-2007 at 07:09 PM.
Apparently there is something.....
I tested several aujp bins on the bench just now and got the same result.
Adjusting the closed throttle or main SA table had no effect till warmer temps.
I didn't check exactly what temp it goes away at.
That will have to be on another night along with some research in the hack.
Well that is interesting. I also have been having idle problems like the post above and with SP you will see the idle jump right down at 45 in my car. Ironically what you are seeing is right where my car starts giving me fits when it is cold. When the car gets to about 60C I can put it in gear without stalling. The table seems to be the SA Temp Correction Vs Load Vs Temp. This has a 45C where you will see the change. I think that combined with your idle setting at that temp will make a difference.
One thing to note here in my observations. 45 is a point where you may be dropping the commanded idle, the SA goes down, MAP goes up, etc. For me with the variable mentioned above it would seem that I would want to raise that value to say 60. I was running closed loop at a low temp then I raised that but again. There maybe multiple tables at play here.
Although Grumpy is describing timing for a 747, he mentions
"Cold spark bias" , and says "This value is subtracted from the
Total SA. It's purpose is to bias the Coolant
compensation spark table. Again, to allow for a
negative advance in this table."
I have not found it, but does the AUJP contain a "Cold spark bias" that is subtracted out of the main spark advance or closed throttle spark advance? If so, that may account for the discrepancy.
The idle SA is calc'd that way. And per his table he has 29* initially.
But once the temp starts moving, the SA moves as posted above.
Testing on the bench showed SA following RPM in that temp region.
And changing the idle spark tables at low temps had no effect on SA.
I thought it was a TP related error until I changed the cool temp corr. & idle error tables and the SA moved as expected.
Once above 44c changing the idle SA table worked.
8D bias has been out for several years. Look at the Super8dm ecu or do a search in the hac on bias......
<snip> bad info
The AUJP hac has been out for over a year, search moates for JPaujp or similar.
If needed, I'll include a bit selectable fix in S_AUJPV4.
But like Red said, lowering the cold disable temp maybe all the fix that's needed.
Last edited by Z69; 03-10-2007 at 04:06 AM.
Reason: incorrect statement
It looks like there is a bias of 20 degrees in the cool comp. SA table. Any value below 20 degrees will cause timing to be pulled as the computed corrections are the value in the table - 20. Right in the middle of your table at around 35-45 degrees C, your pulling around 4-5 deg. of SA at the mid MAP range. Change this to 20 degrees and see if it still seems to pull timing. The engine may wander into those cells and get stuck there in a funk.
Ok, the code does actually do as posted above.
Your problem is your stock coolant comp table goes from adding ~ 7 deg to pulling 5 degrees. Or a delta of 12 deg. Also, when < 44.5 C the code uses the main SA tables 100kpa column.
So as your rpm drops so will the SA since it's following your table. Which explains why some may have and extra hard time with cold idle swings.
Lots of people flaten the low rpm main SA area and zero out the cool comp table in the area it pulls timing. So they never see this as long as the low rpm area matches their clsd throttle tbl.
The code basically removes the MAP from the SA equation until > 44.5c (113f).
Have a look at the axcn cool comp and 100 kpa col. to see how GM handled it with a MT. And it might make more sense.
I'll post how the code works another time.
Now I see what Rbob was getting at when he said people have trouble with the idle SA.
I've seen a few other posts with this problem but it was so poorly stated and presented that they were ignored. By more than just me.
This falls in the catagory of someone who asked a question correctly.
Guys lets keep this thread going! I have had my share of idle problems and I also have had times where behaved perfectly only to go ballistic the next time I started the car. I have also seen my IAC go wild where my counts go to 160+ only to finally settle down which is usualy after it stalls. This is only when I put it in gear at this temp area. I can start the car stone cold then put it in gear no problem and when I am fully warmed up I have no problem with stalling -ever. I have played with O2 constants, IAC steps, etc. Take a look at my ScannerPro thread where I started using it do dataloging. I started at idle with a idle only definition. I am not running a Park/Drive switch and have set the difference to 0 RPM's but I have also had a perfect idle in the past with the same cam. When I went LT1 intake, 1.6RR's and the AFR heads I started having problems. One thing to note here I am using a bleed hole for Split BLM's and an IAC count of 20-30 at temp but it shouldn't make a difference. I think it may be as simple as aluminum heads are more cold blooded and that the temp is to low to go from cold start idle to normal idle. My next test is to change the variable mentioned above to 60C to see if my problems go away.
Alright thanks a lot guys.
So you figured out that before the cold temp spark is disabled, It uses the values in the 100kpa area of the main spark table to make the spark advance temp correction changes?
So to fix this without having to up my 100kpa main spark values I can simply add more spark to the temp correction table as needed and flatten out the lower rpm 100kpa area?
Last edited by mike1986fyrbird; 03-10-2007 at 06:08 PM.
Ok, the code does actually do as posted above.
Your problem is your stock coolant comp table goes from adding ~ 7 deg to pulling 5 degrees. Or a delta of 12 deg. Also, when < 44.5 C the code uses the main SA tables 100kpa column.
So as your rpm drops so will the SA since it's following your table. Which explains why some may have and extra hard time with cold idle swings.
Lots of people flaten the low rpm main SA area and zero out the cool comp table in the area it pulls timing. So they never see this as long as the low rpm area matches their clsd throttle tbl.
The code basically removes the MAP from the SA equation until > 44.5c (113f).
Have a look at the axcn cool comp and 100 kpa col. to see how GM handled it with a MT. And it might make more sense.
I'll post how the code works another time.
Now I see what Rbob was getting at when he said people have trouble with the idle SA.
I've seen a few other posts with this problem but it was so poorly stated and presented that they were ignored. By more than just me.
This falls in the catagory of someone who asked a question correctly.
YES ,keep it going.Is tuner cats coolcomp table wyswyg
Have a look at the axcn tables and you'll get an idea of what to try with your SA numbers instead.
AFA changing the temp constant. I'd say it would be cam dependent.
And it will really depend on how much heat you put into the intake air.
So every combo will be different.
I suspect most problems are caused by the SA tables not being matched well.
Making sure the cool comp table doesn't defeat what your trying to do in the other tables will help.
This thread is great. I have another thread with the same problem in it on the 6E I am running and I will now adjust the Main SA table out in the higher LV8 coulmns to see if that helps.
Ok, here's some text I added to my hac to help explain what's going on for this post.
I can't seem to get it to post in a normal pane though......
Might try cut & paste into word to get a better layout.
This is similar to how it look in my editor.
But the html conversion messes up all sorts of stuff.
And it looks terrible in Firefox.......
Code:
***************************************************
; * MAIN SPARK ADVANCE
; ***************************************************
;.ORG 0xB906
;
LB906: ldx #L8033 ; 400 RPM - 4800 RPM MAIN SPK TBL
LoaD the main SA table address location on the prom into
a memory location that is called "X". (ldx)
brset *L0001,#0x40,LB924 ; b6, Br IF WARM Kickdown enabled
;to do Normal or clsd throttle SA
This is only set if all condition are met to disable the cold SA routine.
If it is set, then skip down to line LB924
ldab *L005D ; FILTERED COOLANT TEMP
cmpb L8031 ; COOL LOW ENOUGH FOR COLD SPARK?
; VALUE to disable Cold SA
; val = 44.5 Deg C (113F)
Check to see if CTS is < or >= 112.5 *F
bcc LB91D ; If > 44.5 Deg C (113F)
; Br AROUND LOGIC IF TOO WARM
If > temp qual, skip down to line LB91D
; ... else
subb *L0060 ; (START UP COOLANT TEMP)
; CALC DELTA COOL TEMP SINCE START UP
; TEMP, (DEG C+40) * (256/192)
Check to see if Current filtered CT - Startup CT is < or >= Startup CT
bcs LB920 ; Br If DELTA NOT BIG ENOUGH
If Startup temp > Current CT - startup CT skip down to line LB920
; .... else
cmpb L8032 ; 151 Deg C, if diff cool > disable cold SA
Check to see if:
Current Filtered CT - start up CT is < or >
Diff cool temp to disable Cold SA routine
bcs LB920 ; br around until CTS increases above L8032
IF < Diff cool temp qual, skip down to line LB920
; .... else
LB91D: bset *L003C,#0x40 ; WARM KICK DOWN REQUEST
Set bit 6 at RAM address L003C
For use in other part of program- which will set L001 bit 6 for use above.
The following 2 lines are done at least once on every startup on
the first time through here.
LB920: ldab #0xB0 ; Val=176, Use (100 kpa col) 1ST WARM PASS
bra LB946 ; BRA around closed throttle SA
; until > L8031- 44.5 Deg C, (113F)
; or until
; current filtered CTS - S/U CTS is > S/U CTS
; and filtered CTS - S/U CTS is > L8032.
Put 176 decimal in a memory location called "B" for use in a value lookup.
The Main SA table address is still in memory for the lookup.
And skip down to line LB946
Skip to here if CT already > 112.5 F on second pass through of SA routine.
Then check to see if the TPS is < or > the idle setting
to determine which SA table to use.
IF > then use the main SA tables by skipping down to line LB93B
and getting the map value for the lookup.
If < then use the closed throttle SA table
; DETERMINE IF CLOSED THROTTLE
; SPARK ADVANCE OR NOMAL SPK ADV
; table is used and look up value
;--------------------------------
LB924: ldaa *L0095 ; CURRENT TPS LOAD VALUE
cmpa L8647 ; 1.2% TPS
bhi LB93B ; IF TPS > 1.2% do normal SPK
;---------------------
; Closed throttle
; spark advance
;---------------------
ldaa *L0058 ; RPM/25 (w Lookup Offset)
cmpa #0xC0 ; Val = 192, RPM Limit for lkup, 4800 RPM
bls LB933 ; Branch IF Less Than 4800 RPM
; ... else
ldaa #0xC0 ; USE 4800 RPM FOR LOOK UP
;--------------------------------------------------
; LK UP CLOSED THROTLE S.A. vs RPM
;--------------------------------------------------
LB933: ldx #L81FD ; CLOSED THROTLE S.A. TABLE, (2d SPK ADV vs RPM)
jsr LE3D8 ; 2D LOOK UP, NO OFF SET
bra LB95C ; STORE S.A.
;--------------------------------------------------
;
; ***************************************************
; * Normal SPK ADV use main or extended table
; ***************************************************
;
;-----------------
; PROCESS MAP for
; BRK POINTS
;-----------------
LB93B: ldab *L0078 ; LINEARIZED EGR CORRECTED MAP VALUE
cmpb #0xA0 ; Val = 160, > 70 Kpa MAP
bcc LB944 ; Br IF YES.. MORE WORK TO DO
; ... else
lsrb ; PERFORM SCALING, DIV / 2
bra LB946 ; .. & Br to do LK UP
LB944: subb #0x50 ; Val = 80, SUB OFFSET FOR CHANGE TO
; 5 Kpa Break POINTS
;-----------------
; PROCESS RPM for
; table CHOICE
;-----------------
Skip to here if CT is < 112.5 F
with the main SA table address already in memory "X".
Memory location "B" has 176 in it to point to the 100Kpa column.
Determine if RPM is high enough to use the extended SA table or not
and lookup the SA using the 100kpa column and the row based on RPM.
And store it in memory for use many lines farther down from here.
LB946: ldaa *L0058 ; RPM/25 (w Lookup Offset)
cmpa #0xC0 ; Val = 192, ABOVE 4800 RPM ?
bcs LB957 ; BR IF Less Than 4800 RPM
; ... else
cmpa #0xE0 ; Val = 224, LIMIT RPM to 5600 for LOOK UP
bls LB952 ;
; ... else
ldaa #0xE0 ; FORCE TO 5600 RPM
LB952: ldx #L8102 ; EXTENDED SPARK TABLE
;
; **********************
; * IF RPM G.T. 4800 RPM
; * 4800 RPM - 5600 RPM
; * SA EXT TABLE
; **********************
bra LB959 ; TO SPK ADV LK UP
LB957: ldaa *L0057 ; Scaled RPM/25
LB959: jsr LE35B ; 3D Look Up
Go look up the SA value with the table address in "X"
The Map value in "B" and the RPM in "A" for use by the lookup routine
LB95C: staa L0456 ; Save Main spark advance in HU, (HU ADDR)
psha ; USE IN PGM, Push to STX
; *******************************************************
Look up the SA compensation (offset) based on CT.
The SA CT compensation bias is subtracted farther down in the code.
; ****************************************************
; * COOLANT SA COMP
; ****************************************************
ldaa *L005D ; FILTERED COOLANT TEMP
cmpa #0xD0 ; Val = 208, Limit COOL DEG FL to 115 C
bls LB968 ; BR IF COOL LT 115c
; ... else
ldaa #0xD0 ; FORCE TO 115c FOR LOOK UP
; ********************
; * COOL SA COMP TABLE
; ********************
LB968: ldx #L8138 ; COOLANT SPARK ADVANCE TABLE
ldab *L007F ; CURRENT MANIFOLD VACUUM
lsrb ; SCALE 10 Kpa PER TABLE Break Point
jsr LE35B ; 3D Look Up (Is LE353 in ANHT)
staa L0457 ; COOL COMP SPK ADV FM 3D LU (HU ADDR)
psha ; SAVE COOL SA ON STX
Ok, here's some text I added to my hac to help explain what's going on for this post.
I can't seem to get it to post in a normal pane though......
Might try cut & paste into word to get a better layout.
The colors are how it looks in the editor I use.
It took a little work to go back and make it look the same here.....
