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've been playing with the $8D code lately and found out something interesting. The hac has this functionality labeled as Stall Saver SA. Only problem is, it looks like it is designed to make sure the engine does stall.
Here are the parameters:
Code:
;------------------------------
; STALL SAVER
;------------------------------
L802A: FCB 32 ; 400 RPM, IF RPM < ENABLE STALL SAVER SA
L802B: FCB 36 ; 450 RPM, IF RPM < & RPM > L802C,
; ENABLE STALL SAVER SA
L802C: FCB 44 ; 550 RPM, IF RPM > & RPM < L802B,
; ENABLE STALL SAVER SA
L802D: FCB 44 ; 550 RPM, IF RPM > DISABLE STALL SAVER SA
What it does is to shut down the EST and force the distributor into bypass mode whenever the RPM falls below the trip point. Once in bypass mode the distributor fires at the reference angle, or base setting.
This is effect can pull a lot of timing out. Poor engine was struggling to run, and barely made it. Happened a couple of times before I looked at the logs and watched the timing fall off. Then a gander at the code and I was surprised.
I am not sure why this routine is implemented like this, but it is. The above 4 settings are now at 0 and will soon find out how that works out. No wonder I was never able to find the SA term that would be required if it added timing. . .
RBob.
This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!
Sponsored Links
Registered users do not see this ad. Click here to register for free!
Just a thought but maybe a stock cam woud generawte more torque with the low timimg value. The instant you add any cam then the self egr'ing means adding timing.
Personnally. I think some of the timing strategies are backward.
Hey RBob, Do you think this could be the cuase for a problem I have been tryin to solve for a year?
When I am driving and hit the brakes and come to a hard fast stop, the engine just runs like crap and tries to die. I can recover if I give it gas and keep the RPM's over 1000. A couple of seconds later it runs like nothings wrong. Thanks Stewart
Originally posted by Doc1of7 Just a thought but maybe a stock cam woud generawte more torque with the low timimg value. The instant you add any cam then the self egr'ing means adding timing.
Personnally. I think some of the timing strategies are backward.
I'd also wonder if the intent was to put the engine in a "happy place" that it had seen before under similar circumstances. Effectively, if the engine was able to start off of the ignition module alone, let's go back there at low engine speeds. If the ECM was doing such a good job controlling things, we wouldn't be in this predicament......
Just some random speculation. Feel free to disregard.
Originally posted by L98FORM89 Hey RBob, Do you think this could be the cuase for a problem I have been tryin to solve for a year?
When I am driving and hit the brakes and come to a hard fast stop, the engine just runs like crap and tries to die. I can recover if I give it gas and keep the RPM's over 1000. A couple of seconds later it runs like nothings wrong. Thanks Stewart
Very good possibility. Your '89 would be running the $6E code which has the exact same 'stall saver SA' routine. Just set the parameters lower and check it out.
It works, changing those 4 entries to 0 eliminated the Stall Maker SA. As the clutch was being let out the engine RPM dipped down and recovered nicely. The SA actually increased as the idle correction SA came into play.
The IAC opened to correct the low idle and the car basically drove itself into the garage.
Originally posted by 91L98Z28 Just out of curiosity...does this mean that timing is under ECM control during initial startup (while cranking the starter)?
or is stall saver only invoked after the engine is actually running..
Still cranks at initial timing. There is another term used for the RPM switchover to EST for crank to run.
Hey RBob,
I'm having another separate problem but it brought me to a part of the code that has something in common with the stall saver code.
When I'm in DFCO the program reverts to base timing and if I get out of DFCO by getting on the throttle, it'll slowly add timing back until it's at the advance I actually want. i.e 10(base), 10.3, 10.6, 10.9...and so on until it gets to the actual timing from the main spark table. It only does that if the TPS is above the enable TPS% for DFCO, not for the RPM or MAP conditions, in which case timing will jump back to normal immediately. I want to reduce or eliminate this.
I dug into the code a bit (I can only understand little bits). There's a SA blend value for DFCO and SA. This value(L013B) is multiplied by the spark advance to get the actual spark advance. Normally it's at 255 but it DFCO and stall saver change it. The bin location for Stall Saver SA Blend Steps is at $802E. I think changing this would have some effect on the timing. I don't understand enough to figure it out but it looks like SA Blend Steps controls how fast timing returns to normal? Does it make sense?
Code:
LB31D: INCB ; INCR CNT'R
STAB L012B ; DRP CNTR FOR COLD START ELIMN
LB321: BRCLR L0033,#$04,LB344 ; BR IF not b2
; B2 1 = EST ENABLE
; ... else
BRSET L00BB,#80,LB344 ; BR IF b7
; SA RETARDED
; ... else
BRSET L0016,#$02,LB344 ; BR IF b1,
; IN DECEL FUEL C/O STALL SAVE
; IF ERR CNTR NON ZERO
; ... else
LDAA $85F3 ; 2 CNT'S ADDED TO SA BLEND/DRP
LDX L009B ; STALL SAVER TIMER
BNE LB337 ;
; ... else
LDAA $802E ; 16 CNTS ADDED TO SA BLEND EACH DRP
LB337: ADDA L013B ; SPK ADV BLEND MULT
BCC LB341 ; BR IF BLEND NOT FINISHED
; ... else
LDAA #255
BCLR L0039,#$20 ; clr b5, SPARK BELEND IN PROG FLAG
LB341: STAA L013B ; SPK ADV BLEND MULT
It looks like the count at $802E controls how quickly the SA blends from base to controlled at startup.
The DCFO uses the term at $85F3 to blend the SA back in. The term at $85F2 is used whenever the ECM is in DFCO. This will reduce and hold the SA until DFCO exits.
Try increasing the term at $85F3 and see if that blends the SA back in faster. Can also try increasing the term at $85F2. This may cause a bit of a jump once the fuel comes back on.
Originally posted by RBob Very good possibility. Your '89 would be running the $6E code which has the exact same 'stall saver SA' routine. Just set the parameters lower and check it out.
RBob.
RBob,
Is there a parameter in the 7747 code that corresponds to this? I have seen this very condition in my scans when the engine begins to stumble and finally shutdown. The last frame I get usually has a SA timing of 9.8 which is the base timing I have in the Constant Table.
Is there a parameter in the 7747 code that corresponds to this? I have seen this very condition in my scans when the engine begins to stumble and finally shutdown. The last frame I get usually has a SA timing of 9.8 which is the base timing I have in the Constant Table.
None that I am aware of. Also, when outputting [sic] the SA to the ALDL the base timing needs to be added after the fact.
The SA term that is output does not include the base timing advance. So in reality that is 20 deg of SA (when the engine has 10 deg of base or initial timing).
The scans I have include the base timing using the formula you sent on converting the scan information. I just changed the ALDL sream to put the SA data where the INT would go. Not sure how to read that. Output is different than what I got when I sent it to the O2 Voltage.
Originally posted by RBob I've been playing with the $8D code lately and found out something interesting. The hac has this functionality labeled as Stall Saver SA. Only problem is, it looks like it is designed to make sure the engine does stall.
Rbob,
Are you talking about these Constants:
(Stall Saver Spark Adv. on RPM Threshold 1)
(Stall Saver Spark Adv. on RPM Threshold 2)
(Stall Saver Spark Adv. on RPM Threshold 3)
(Stall Saver Spark Adv. off RPM Threshold )
And if so, your saying setting the to 0 rpm will disable this routine.
Louis
__________________
Louis
2001 Supercharged Suburban 4x4.
99 Buick Regal GS Supercharged.
92 Convertable Z28 Supercharged 355cid, 9.5 to1, tpi Auto:
All Forged internals, 6in rods, w/Paxton VR4 13psi, CC blower cam .560 .570 @ .230 .235 dur @ .50 114LS, Ram air mod,100% methanol injection intercooling. W/ PAC controller,52mm T/B,ASM Large tube runners, ported upper & lower TPIS Bigmouth intakes,AFPR set to 55psi,32# injectors,1.6 Pro Magnum roller rockers,slp 1 3/4 headers,3in. cat,3in. gale banks cat back system,3.42 gears,17x9.5 Front, 17x11 Rear, Vett ZR1 wheels, 275x40x17 Front, 315x35x17 Rear G-Force tires,and much more, Check my web site for pics and mods. http://www.lbsz28blown.cz28.com
Originally posted by LBSZ28BLOWN Rbob,
Are you talking about these Constants:
(Stall Saver Spark Adv. on RPM Threshold 1)
(Stall Saver Spark Adv. on RPM Threshold 2)
(Stall Saver Spark Adv. on RPM Threshold 3)
(Stall Saver Spark Adv. off RPM Threshold )
And if so, your saying setting the to 0 rpm will disable this routine.
Louis
I listed the four parameters in the opening post of this thread. I later posted that setting all four parameters to 0 eliminated the stall saver SA.
Originally posted by RBob I listed the four parameters in the opening post of this thread. I later posted that setting all four parameters to 0 eliminated the stall saver SA.
RBob.
RBob,
Can I change the four parameters using the pocket programmer's edit buffer? If so, where do I start because I don't understand computer jargon. I tried doing it in the constant tables, yeilding no change and the car still stubbles a little when put in gear and after reving the engine in park hunting for a stable idle. I've also made sure IAC is @ 0 as mentioned in other tuning threads posted by Traxion and other tuning guru's such as yourself. Other than that the car runs good. Also I'm running a 234/242 w/.539/.558 lift, 112 LSA. Help me out. If you can. I tried to do it on my own, then I got lost in the code stuff! Got to learn on my own some time LOL.
Originally posted by zz17iroc RBob,
Can I change the four parameters using the pocket programmer's edit buffer? If so, where do I start because I don't understand computer jargon. I tried doing it in the constant tables, yeilding no change and the car still stubbles a little when put in gear and after reving the engine in park hunting for a stable idle. I've also made sure IAC is @ 0 as mentioned in other tuning threads posted by Traxion and other tuning guru's such as yourself. Other than that the car runs good. Also I'm running a 234/242 w/.539/.558 lift, 112 LSA. Help me out. If you can. I tried to do it on my own, then I got lost in the code stuff! Got to learn on my own some time LOL.
Thanks
Can edit the bin that way, can also use a hex editor or other such program. The locations shown in the first post of this thread are the virtual addresses. In order to get the EPROM physical address need to subtract 0x800 off the address:
L802A - 8000 = 2A
So $2A will be the address of the first location. With the other three following: $2B, $2C, $2D. Zero out those four locations.
Running $6E, After reading what you guys are saying here it sounds like if I reduce RPM in my Stall Savers the car is less likely to stall. I have stalling problems/low rpm issues when shifting in and out of gear. Will changing the stall saver help me?
Originally posted by RBob Can edit the bin that way, can also use a hex editor or other such program. The locations shown in the first post of this thread are the virtual addresses. In order to get the EPROM physical address need to subtract 0x800 off the address:
L802A - 8000 = 2A
So $2A will be the address of the first location. With the other three following: $2B, $2C, $2D. Zero out those four locations.
RBob.
Cool. I'll try it after I finish installing my Alston subframe connectors. Thanks for your help bro!
__________________ 88 Iroc w/383 eagle forged assembly, Accel Pro-Ram, ZEX nos plate, 1200cfm TB, 847 cam, Trickflow 195, Hooker LT coated w/Mufflex y-pipe and 4" Ultra-Flo, Pro-Built tranny, 3500 stall, Moser 12bolt 3.73's, Spohn suspension throughout, 315 ZR1's rear and 275 ZR1's front, Weld Drag Lites w/ M/T drag radials and front skinnies on 165's for the strip. Speed Density swap and Innovate LM1 WB.
