secondary removal how do you go......

[bradslt5]

about it . could someone who has donerthis give me the proceedure for rmoving them. and what does one have to keep connected vaccume wise ? does the prom need to be reburned ? and who does this ? also where can one get the accel injectors ? and what part numbers . thanx in advance for any help

[Paul Workman]

about it . could someone who has donerthis give me the proceedure for rmoving them. and what does one have to keep connected vaccume wise ? does the prom need to be reburned ? and who does this ? also where can one get the accel injectors ? and what part numbers . thanx in advance for any help

I'm strongly considering removing them as well; "parts left out never break", is the way I look at it.

Pete has removed his and likes the results just fine. And, I spoke w/ Marc Haibeck about it and as it happens he has a chip profile to accomodate the modification, and is experimenting with a new table which (to me) appears to actually boost the low-mid torque a smidgen as well as adding about 5 ponies to the top end.

So, I wonder if the mod adversely affects emmissions?? If not, then it really seems to be a "no brainer" to pull them and install Marc's chip.

P.

[Pete]

You will need to keep the electric secondary solonoid,vacuum pump and
differantial MAP(under ECM early) (under plenum later).

You will need to run from the Differantial MAP to the open port of the solonoid the vacuum pump to the closed port of the solonoid.


Make sure you yank everything else shafts included use Dorman freez-plug #555-108 or equal local part store.

Make sure you have Full Power ON when you go for a test drive.
Enjoy.

This is what i can remember off the top of my head,age is catching up to my memory.

If you need more info just post.
Pete

[tpepmeie]

Or you could reprogram the PROM to avoid all the secondary vacuum checks....

Pete, did you get the other info I sent the other day?

Todd

[Pete]

Or you could reprogram the PROM to avoid all the secondary vacuum checks....

Pete, did you get the other info I sent the other day?

Todd


What Todd said reprograming the chip.

Yes,got it Todd thanks.

Pete

[XfireZ51]

What Todd said reprograming the chip.

Yes,got it Todd thanks.

Pete

Does that mean unchecking the MALF flags for PRT 56 and PRT 61? I'm interested in knowing since I'll be pulling plenum in the near future and thinking about removing SCDYs.

[bradslt5]

who can reprogram the prom to do what todd said ?one last question do you have to remove the head to pull the secondary butterflies and shafts out . pete on my cam settings 1141/2 and 1121/2. have a rear end problem on the black car so havent had a chance to dyno. will be a while now with moving in to the new house and shop.

[tpepmeie]

Does that mean unchecking the MALF flags for PRT 56 and PRT 61? I'm interested in knowing since I'll be pulling plenum in the near future and thinking about removing SCDYs.

No, that won't do it. That flag won't disable the error from setting. The vacuum check is done as a form of converter protection. (sounds weird, I know) There are a couple of options to avoid this... one way is to modify the program to jump around the vacuum checks altogether, or change the conditions which cause the PTs not to open.

Todd

[XfireZ51]

No, that won't do it. That flag won't disable the error from setting. The vacuum check is done as a form of converter protection. (sounds weird, I know) There are a couple of options to avoid this... one way is to modify the program to jump around the vacuum checks altogether, or change the conditions which cause the PTs not to open.

Todd

Todd,

Thanks. That helps. So the ECM thinks the Scndys are closed and not expecting any indicator.
But if you do the latter, how does it know to use the Open PT VE and SA tables? :-D

[karterdon]

BAck to one of your original questions - accel Injectors??
I got mine from - Atlantic Speed 1/803/548-6990 ask for Scott. Ask if he gives a discount for ZR1 memebrs or Corvette Forum members - He will then give you a discount - I paid $498 for 16 of them.

Part # acc150121

D.Y. 91-#267
:thumbsup:

[Pete]

BAck to one of your original questions - accel Injectors??
I got mine from - Atlantic Speed 1/803/548-6990 ask for Scott. Ask if he gives a discount for ZR1 memebrs or Corvette Forum members - He will then give you a discount - I paid $498 for 16 of them.

Part # acc150121

D.Y. 91-#267
:thumbsup:


That's a good price.

Pete

[bradslt5]

wow, thanx for the info, thats why i love it here ,a bunch of guys sharing and caring enough to help:thumbsup:

[XfireZ51]

While we're on the topic of secondary PT removal, Lgaff and myself discussed the idea of just removing the throttle plates and leaving the rest of the linkage in. ECM still thinks secondaries are in. Everything works except no throttle blades in the way. And since we haven't determined yet how to bypass a MALF for SCDY PT, this seemed like a reasonable way to go. Any comments?

[XfireZ51]

While we're on the topic of secondary PT removal, Lgaff and myself discussed the idea of just removing the throttle plates and leaving the rest of the linkage in. ECM still thinks secondaries are in. Everything works except no throttle blades in the way. And since we haven't determined yet how to bypass a MALF for SCDY PT, this seemed like a reasonable way to go. Any comments?

Anything further on "reprogramming the chip" if secondaries aren't used? What happens to use of PT Throttle Open VE and SA tables if the parameters for using secondaries is set high in order to avoid setting a code?
Any comments on simply removing the butterflies and leaving everything else intact?

[Maxlean]

Anything further on "reprogramming the chip" if secondaries aren't used? What happens to use of PT Throttle Open VE and SA tables if the parameters for using secondaries is set high in order to avoid setting a code?
Any comments on simply removing the butterflies and leaving everything else intact?
That's what we did. Kept the solenoid, pump, and diff map but took out the butterflys and shafts. Then in the prom, I duplicated the pt open sa and ve tables to the closed pt sa and ve tables. Works like a charm. The ecm thinks it's switching the secondaries, and using the different tables, but in reality is just using the pt open tables at all times. BTW, just setting the pt open point to be some really low value (as our chip was delivered) is not a good idea as since the ecm thinks it's in pt open mode it only uses 3 of the 19 ft cells. This can have a real impact on driveabilty (especially if your ve tables aren't perfect). Doing it the way I suggest allows the ecm to use all ft cells under normal driving as it thinks the pt's are closed.
Scott

[tpepmeie]

BTW, just setting the pt open point to be some really low value (as our chip was delivered) is not a good idea as since the ecm thinks it's in pt open mode it only uses 3 of the 19 ft cells.Scott

There is nothing in the program to limit block learn cells when the port throttles are open. Whether PT open or not should have not effect on the block learn function.

Open port throttles does not mean power enrichment is active.

Todd

[XfireZ51]

Max,

So you've left the PT settings alone and duplicated the VE and SA tables?
I was thinking of taking the butterflies off the shafts but leaving the shafts in. Any comments on how detrimental that would be to maximizing performance?

[tpepmeie]

Dom,
What benefit are you trying to achieve by removing the butterflies? At part throttle, and perhaps full throttle below 3500 rpm, there will be a torque loss. At least up to the 500hp/350 level. I experimented thoroughly a couple of years ago, by datalogging, and clearly saw higher MAP values at cruise with the PTs Open. This is indicative of a loss of torque output.

Others have proven that on a big inch, or even heavily modded out 350, that a full throttle dyno run doesn't necessarily show a torque loss w/ no PTs in place. While I believe that, I have wondered at what RPM the dyno runs started. My observations are that the cross-over point is near 3000-3500 RPM. I suspect that larger displacements will lower than cross-over point.

On all but the most extreme calibrations I do, I have set the Port throttle opening point slightly later than the factory setting. There is a noticeable gain in Part Throttle torque, and have not had anyone complain.

Todd

[XfireZ51]

Dom,
What benefit are you trying to achieve by removing the butterflies? At part throttle, and perhaps full throttle below 3500 rpm, there will be a torque loss. At least up to the 500hp/350 level. I experimented thoroughly a couple of years ago, by datalogging, and clearly saw higher MAP values at cruise with the PTs Open. This is indicative of a loss of torque output.

Others have proven that on a big inch, or even heavily modded out 350, that a full throttle dyno run doesn't necessarily show a torque loss w/ no PTs in place. While I believe that, I have wondered at what RPM the dyno runs started. My observations are that the cross-over point is near 3000-3500 RPM. I suspect that larger displacements will lower than cross-over point.

On all but the most extreme calibrations I do, I have set the Port throttle opening point slightly later than the factory setting. There is a noticeable gain in Part Throttle torque, and have not had anyone complain.

Todd

Todd,

I really appreciate that perspective. As you've noted, there are several members that recommend removing the secondaries. Marc Haibeck indicated his experience on this issue is the same as yours. No measurable difference. Clearly, if you've noted higher MAP readings at PT with secondaries removed, having secondaries "in" must help in PT response.
I was looking for a way of retaining the secondary mechanism while "gaining" flow and avoiding the MALF issue. Based on what you've described, I'll leave them alone at this point. The plans for my motor don't call for anything very radical. A very streetable 12sec. car is my goal.
We'll see how it goes once I put on my ported top end in the next few weeks.

[LGAFF]

I am no expert, and I would agree a person would expect torque loss w/removal of the secondaries.....that said, the snakerskinner program removed and siamesed the runners, and ended up with more torque, making launching at anything over 1800rpm impossible. The car had exhaust mods, and advanced cams, but was a stock 350.

Anyone know who was involved in that program? The only name I have is Scott Leon who was the GM rep who oversaw testing. Would be interesting to know what they did and why, with secondaries.


LGAFF
92 ZR1
#234

[Maxlean]

There is nothing in the program to limit block learn cells when the port throttles are open. Whether PT open or not should have not effect on the block learn function.

Open port throttles does not mean power enrichment is active.

Todd
I'm gonna have to beg to differ. When driving around with the pt commanded open (setting them at a very low value) I would only use cells 16 17 and 18 (or something like that, I'd have to check my logs). When the pt were commanded closed, all cells were available (EXCEPT 18). I suspected that when the pt's are commanded open, the ecm assumes power mode (but not necessarily pe) and therefore really only needs one cell for that mode of operation. In other words cell 18 is dedicated to pt open mode (still closed loop), just as cell 16 is idle and 17 is decel. (disclaimer: the actual cell numbers may be different than these, memory ain't what it used to be!)
Scott

[tpepmeie]

Scott,
You are free to differ if you want. I have the source code. What model year, and I will review the code again tonight to be sure.

[threestar40]

This is a re post from 5/06 on that other site...the reason I still have my secondaries...and I hate extra complicated equipment as well, so I own a ZR1:icon_scra I did do coil overs with an FX3 delete though...so I got that going for me.

When I read lingenfelters book on modifying small block chevy's, he talked a lot about intake velocity.

At the lower RPMs, smaller passages=more intake velocity thus making more power and torque and at the higher RPM's you want more volumetric area as the motor is pulling all the air it can and intake velocity for cylinder filling is not as much an issue.

I thought that was the idea behind how our stock throttle bodies' work as well. Have ya'll looked at how small that little primary butterfly is?

It's tiny...I think we need to keep our eye on the ball here.

Let me quote John.

"Intake runner length is one of the critical decisions in engine building since it contributes significantly to the shape of the power curve"

"Condensing this very complex subject down to it's basic concepts, increasing runner length tends to improve torque at the lower RPM levels while simultaneously lowering the peak torque RPM point"

Now I realize that he is speaking about a different motor, but there is knowledge to be gained here.

"The other half of the intake manifold design process, cross-sectional area of the port, also plays an important role. Generally a smaller runner area increases intake charge velocity, speeding up the inlet charge, which improves cylinder filling at lower RPM levels. Conversely, huge intake manifold port runners contribute to slowing the intake gas speed at lower RPM levels, hurting power below peak torque while contributing to improved cylinder filling at RPM levels closer to peak horsepower."

One more thing which I feel is a jewel should be mentioned here.

On a section titled "manifold destinies" (Love it, Every ZR1 owner should albeit bittersweet)

"As you can see, there are several intake tuning factors that remain constant...Intake runner size is perhaps the most important. Small runners generate great low speed torque but tend to limit top end power. Runners that are too large will be lazy at street engine speeds and contribute to exhaust dilution/reversion in the intake. Short length runners tend to emphasize top-end power while longer runners tend to increase mid-range torque at some sacrifice of top-end RPM power potential. This is about as concise as you can get yet there are plenty of questions still to be answered. The future of induction tuning will address all of these factors plus a dozen more." NOW THIS IS TH IMPORTANT PART. PAY ATTENTION "How about a variable-length, variable-diameter intake that could be long and small for good low-end power and short and fat for top end power? If that sounds too much like Buck Rogers, it's already happenend in Formula 1. Perhaps some enterprising Hot Rodder will someday build as practical and affordable and intake for the small block Chevy! Think about it."

The bastards should have designed it better so it doesn't break all the time.

Eyes on the ball.

Rick

[XfireZ51]

I'm gonna have to beg to differ. When driving around with the pt commanded open (setting them at a very low value) I would only use cells 16 17 and 18 (or something like that, I'd have to check my logs). When the pt were commanded closed, all cells were available (EXCEPT 18). I suspected that when the pt's are commanded open, the ecm assumes power mode (but not necessarily pe) and therefore really only needs one cell for that mode of operation. In other words cell 18 is dedicated to pt open mode (still closed loop), just as cell 16 is idle and 17 is decel. (disclaimer: the actual cell numbers may be different than these, memory ain't what it used to be!)
Scott

Scott,

I have to agree with Todd. PT Open doesn't automatically mean the ECM is in PE mode. Several other parameters that define PE.

Rick,

What's the image you posted?

[threestar40]

Those images were just smilies from the other forum...I just cut and pasted.

Sorry.

It wasn't anything exciting.

Rick :happy1:

[tomtom72]

I would just like to thank all of you guys for this disscussion.....I'm learning, and that's great.

Rick, thank you for reminding me to remember stuff I kind of "got" back in the early 70's.....on my LT-1 motor. This is just an observation from the peanut gallery...it seems to me that Mr. Lingenfelter was sort of describing the intake system on a LT5???:o

:cheers:
Tom

[Maxlean]

Scott,

I have to agree with Todd. PT Open doesn't automatically mean the ECM is in PE mode. Several other parameters that define PE.

Rick,

What's the image you posted?

Hold on. I'm not saying that it's pe mode at all. I'm saying that cell 18 is dedicated to pt open mode (still closed loop), just as there are other specialized cells such as 16 for idle mode and 17 for decel mode. While datalogging with the pt open, I was only using cell 18 durring normal driving. Durring decel 17 was used and at idle 16 was used. Setting it for normal opperation (pt closed durring normal driving), all the remaing cells were now being used. Try it yourself. BTW, this is '90 with the prom being based on the latest factory release.
Scott

[tpepmeie]

Do you have a copy of that datalog you could send me? Which diagnostic software?

I've looked again through the entire 90 source code (& others). No link whatsoever that I can find between the PT Open bit and the BLM cell. I have never, ever seen BL cell 18 in any of my logs. It is only a 16-byte table.

Todd

[Maxlean]

I'm using TTS Datamaster to log. I've got one I could email too you if your interested.
Scott

[tpepmeie]

All,
I have found the relevant section of code. It does not exist in all calibrations, and I had overlooked it before. Will write more later. Learned something new today.... :)

Todd

[XfireZ51]

I'm using TTS Datamaster to log. I've got one I could email too you if your interested.
Scott


Max,

Good catch! :worship:

[tpepmeie]

Well, at least I have figured out that this routine is only present on 4 calibrations, and AYBK is one. That happens to be the cal which MaxLean is using.

These calibrations use a 20-byte BLM table (0-15, 16, 17, 18, 19), whereas all the other LT5 use 16-bytes (0-15). I remembered now that BMCB used 20, but never could determine why.

More to follow.

[XfireZ51]

Todd,

So this is limited to 90-91 ZRs? Any idea why they would remove that?

[tpepmeie]

Todd,

So this is limited to 90-91 ZRs? Any idea why they would remove that?

No. The only pre-93 calibration this exists in is the AYBK, and that was a service release not original equipment. Having said that, even some later released service cals, don't have it! Very wierd.

Todd

[XfireZ51]

No. The only pre-93 calibration this exists in is the AYBK, and that was a service release not original equipment. Having said that, even some later released service cals, don't have it! Very wierd.

Todd

Todd,

Any speculation on the function?

[tpepmeie]

update -- I've finally had a chance to look at this. Several things going on...

cell 16 is the idle cell, used if tps < 1.8% and rpm < 1800.
cell 17-19 are used when the 2ndary fuel injectors are on. The cells are divided by the normal RPM boundaries.

I'll post the code, although the formatting is not perfect. So I'll attach a txt file for easier reading.
253

Todd



*################################################# ####
*# BLOCK LEARN CELL UPDATE ROUTINE
*# CELLS 0-15 FOR NORMAL OPERATION
*# CELL 16 FOR IDLE CONDITIONS (LOW TPS, LOW RPM)
*# CELLS 17-19 USED WHEN PT OPEN TO 2NDARY'S ON
*# DELAY IS OVER
*################################################# ####

************************************************** ****
* GET BLOCK LEARN MULTIPLIER AND ITS CELL
************************************************** ****
GETBLM BCLR MWFA;BIT2 BLOCK LEARN ADDRESS CHANGE FLAG = 0
LDAB BLMCELL FETCH CURRENT BL CELL
CMPB #15
BLS BLIDLCHK IF BL CELL <= 15, GO CHECK FOR IDLE STATE
CMPB #16
BNE BLMPTCHK IF BL CELL > 16, GO CHECK PT STATUS

************************************************** ****
* TEST FOR CONDITIONS TO REMAIN IN IDLE BLM CELL (16)
************************************************** ****
LDAA KTPSBLML IF BL CELL = 16, CHECK THRESHOLDS TO REMAIN IN IDLE CELL
ADDA KTPSBLHY ADD HYSTERESIS TERM (0.8%) TO MIN TPS FOR CELL 16 (1.2%)
BCS LD0CB
CMPA NTPSLD
BCS GETBLM4A BR IF TPS > LIMIT; THEN NEED TO CHANGE CELL
GETBLM1CLDAA KRPMBLML FETCH RPM THRESHOLD (1800)
ADDA KBLESHY ADD HYSTERESIS TERM (50 RPM) TO MIN RPM FOR CELL 16 (1800)
BCS GETBLM2A
CMPA NTRPMX
BCS GETBLM4A BR IF RPM > LIMIT; THEN NEED TO CHANGE CELL
JMP LD176 IF ALL OK, THEN STAY IN CELL 16

************************************************** ****
* TEST FOR CONDITIONS TO REMAIN IN PT OPEN CELLS (17-19)
************************************************** ****
BLMPTCHKBRCLR MW1;BIT1,GETBLM4AIF CELL > 16 AND PT DELAY OVER, GO TO NORMAL BLM ROUTINE
… OTHERWISE IF DELAY NOT OVER
ANDB #3 …. RPMINDEX = BITS 0,1 OF BLMCELL
SUBB #1
LDX #KBLESB1A BLM CELL RPM BOUNDARY--LOW
ABX DETERMINE LOWER RPM BOUNDARY OF CURRENT BLCELL
TSTB IF RPMINDEX = 0, THERE IS NO LOWER BOUNDARY TO CHECK
BEQ GETBLM11
LDAA 0,X
SUBA KBLESHY SUBTRACT HYSTERESIS VALUE TO FORM LOWER RPM LIMIT
BCS GETBLM09
CMPA NTRPMX
BHI GETBLM4A BR IF RPM < LIMIT; CELL HAS CHANGED
GETBLM09CMPB #2 IF RPMINDEX = 2, THERE IS NO UPPER BOUNDARY TO CHECK
BEQ GETBLM2A
GETBLM11LDAA 1,X
ADDA KBLESHY ADD HYSTERESIS VALUE TO FORM UPPER RPM LIMIT
BCS LD176
CMPA NTRPMX
BCS GETBLM4B BR IF RPM > LIMIT; CELL HAS CHANGED
GETBLM2ABRA LD176

GETBLM4AJMP GETBLM4B

************************************************** ****
* TEST FOR CONDITIONS TO ENTER IDLE CELL (16)
************************************************** ****
BLIDLCHKLDAA NTPSLD IF CURRENT CELL <= 15, CHECK FOR IDLE STATE
CMPA KTPSBLML COMPARE CURRENT TPS WITH THRESHOLD (1.2%)
BHI GETBLM2B IF TPS > MIN GO CHECK PT STATUS
LDAA NTRPMX
CMPA KRPMBLML COMPARE CURRENT RPM WITH THRESHOLD (1800)
BHI GETBLM2B IF RPM > MIN GO CHECK PT STATUS
LDAB #16 IF TPS AND RPM BELOW LIMIT, USE CELL 16
JMP GETBLM60 GO STORE BLM CELL = 16

************************************************** ****
* NORMAL BLM ROUTINE BEGINS HERE
************************************************** ****
GETBLM2BBRSET MW1;BIT1,GETBLM4BBR IF PORT THROTTLE TO 2NDARY'S ON DELAY OVER

LDAB BLMCELL
ANDB #3 …. RPMINDEX = BITS 0,1 OF BLMCELL
LDX #KBLESB1A-1 BLM CELL RPM BOUNDARY--LOW
ABX DETERMINE LOWER RPM BOUNDARY OF CURRENT BLCELL
TSTB IF RPMINDEX = 0, THERE IS NO LOWER BOUNDARY TO CHECK
BEQ GETBLM15
LDAA 0,X
SUBA KBLESHY BLM RPM HYSTERESIS
BCS GETBLM10
CMPA NTRPMX
BHI GETBLM4B
GETBLM10CMPB #3
BEQ GETBLM20
GETBLM15LDAA 1,X
ADDA KBLESHY BLM RPM HYSTERESIS
BCS GETBLM20
CMPA NTRPMX
BCS GETBLM4B
GETBLM20LDAB BLMCELL
ANDB #12
LSRB
LSRB
LDX #KBLESB3 BLM CELL RPM BOUNDARY--HIGH
ABX
TSTB
BEQ GETBLM35
LDAA 0,X
SUBA KBLPMHYA BLM MAP HYSTERESIS
BCS GETBLM30
CMPA MAPSD
BHI GETBLM4B
GETBLM30CMPB #3
BEQ GETBLM36
GETBLM35LDAA 1,X
ADDA KBLPMHYA BLM MAP HYSTERESIS
BCS GETBLM36
CMPA MAPSD
BCS GETBLM4B
GETBLM36LDAB BLMCELL MAPINDEX = BITS 2,3 OF BLMCELL
BRA GETBLM60

************************************************** ****
* PT OPEN CELLS, ADJUST BASED ON RPM
************************************************** ****
GETBLM4BBSET MWFA;BIT2+BIT3 SET BLOCK LEARN UPDATE AND CELL CHANGE
LDAB #16
LDAA NTPSLD
CMPA KTPSBLML COMPARE TPS TO THRESHOLD (1.8%)
BHI GETBLM4C
LDAA NTRPMX
CMPA KRPMBLML COMPARE RPM TO THRESHOLD (1800)
BLS GETBLM60
GETBLM4CINCB IF TPS AND RPM ARE ABOVE IDLE LIMIT, INCR BLM TO NEXT CELL
BRCLR MW1;BIT1,GETBLM40IF PT DELAY IS NOT OVER, THEN GOTO NORMAL BL ROUTINE

LDAA NTRPMX
CMPA KBLESB2 BLM CELL RPM BOUNDARY--MID
BLS GETBLM60
INCB INCREMENT BL CELL IF RPM HIGHER THAN BOUNDARY
CMPA KBLESB3 BLM CELL RPM BOUNDARY--HIGH
BLS GETBLM60
INCB INCREMENT BL CELL IF RPM HIGHER THAN BOUNDARY
BRA GETBLM60

GETBLM40CLRB BLMCELL = 0
LDAA NTRPMX MODIFY BLM CELL LOCATION BASED ON RPM
CMPA KBLESB1A BLM CELL RPM BOUNDARY--LOW
BCS GETBLM50
INCB BLMCELL = BLMCELL + 1.0 (IN COLUMN 1)
CMPA KBLESB2 BLM CELL RPM BOUNDARY--MID
BCS GETBLM50
INCB
CMPA KBLESB3 BLM CELL RPM BOUNDARY--HIGH
BCS GETBLM50
INCB
GETBLM50LDAA MAPSD MODIFY BLM CELL LOCATION BASED ON MAP
CMPA KBLPMB1A BLM CELL MAP BOUNDARY--LOW
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
CMPA KBLPMB2A BLM CELL MAP BOUNDARY--MID
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
CMPA KBLPMB3A BLM CELL MAP BOUNDARY--HIGH
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
GETBLM60STAB BLMCELL STORE BLM CELL
LDX #LBLMM POINT TO LEFT BANK BLM CELLS
ABX BLMADD = BLMM + BLMCELL
LDAA 0,X
CMPA KBLMMAX IF BLM VALUE IS OUT OF RANGE, INDICATE
BHI GETBLM65 …NVRAM FAILURE AND INITIALIZE B/L TABLE
CMPA KBLMMIN
BCS GETBLM65
TSTA TEST LEFT BLM
BMI GETBLM85 LIMIT LEFT PE BLM TO 128 - BR IF ALREADY >= 128
BRCLR MWFA;BIT5,GETBLM85BR IF NOT IN PE

LDAA #128 IF IN PE USE LEFT BLM VALUE >= 128
GETBLM85STAA LBLM SAVE FINAL LEFT BLM
LDX #RBLMM POINT TO RIGHT BANK BLM CELLS
ABX BLMADD = BLMM + BLMCELL
LDAA 0,X
CMPA KBLMMAX IF BLM VALUE IS OUT OF RANGE, INDICATE
BHI GETBLM65 …NVRAM FAILURE AND INITIALIZE B/L TABLE
CMPA KBLMMIN
BCS GETBLM65
TSTA TEST RIGHT BLM
BMI GETBLM84 LIMIT RIGHT PE BLM TO 128 - BR IF ALREADY >= 128
BRCLR MWFA;BIT5,GETBLM84BR IF NOT IN PE

LDAA #128 IF IN PE USE RIGHT BLM VALUE >= 128
GETBLM84STAA RBLM SAVE FINAL RIGHT BLM
BRA GETBLMEX

GETBLM65BSET CLCCMW;BIT6 NV RAM FAILED FLAG = 1
LDAA #128
CLRB
LDX #32
BLMINITCSTAA LBLMM-1,X
DEX
BNE BLMINITC

STAA LBLM
STAA RBLM

GETBLMEXEQU *

[Maxlean]

update -- I've finally had a chance to look at this. Several things going on...

cell 16 is the idle cell, used if tps < 1.8% and rpm < 1800.
cell 17-19 are used when the 2ndary fuel injectors are on. The cells are divided by the normal RPM boundaries.

I'll post the code, although the formatting is not perfect. So I'll attach a txt file for easier reading.
253

Todd





*################################################# ####
*# BLOCK LEARN CELL UPDATE ROUTINE
*# CELLS 0-15 FOR NORMAL OPERATION
*# CELL 16 FOR IDLE CONDITIONS (LOW TPS, LOW RPM)
*# CELLS 17-19 USED WHEN PT OPEN TO 2NDARY'S ON
*# DELAY IS OVER
*################################################# ####

************************************************** ****
* GET BLOCK LEARN MULTIPLIER AND ITS CELL
************************************************** ****
GETBLM BCLR MWFA;BIT2 BLOCK LEARN ADDRESS CHANGE FLAG = 0
LDAB BLMCELL FETCH CURRENT BL CELL
CMPB #15
BLS BLIDLCHK IF BL CELL <= 15, GO CHECK FOR IDLE STATE
CMPB #16
BNE BLMPTCHK IF BL CELL > 16, GO CHECK PT STATUS

************************************************** ****
* TEST FOR CONDITIONS TO REMAIN IN IDLE BLM CELL (16)
************************************************** ****
LDAA KTPSBLML IF BL CELL = 16, CHECK THRESHOLDS TO REMAIN IN IDLE CELL
ADDA KTPSBLHY ADD HYSTERESIS TERM (0.8%) TO MIN TPS FOR CELL 16 (1.2%)
BCS LD0CB
CMPA NTPSLD
BCS GETBLM4A BR IF TPS > LIMIT; THEN NEED TO CHANGE CELL
GETBLM1CLDAA KRPMBLML FETCH RPM THRESHOLD (1800)
ADDA KBLESHY ADD HYSTERESIS TERM (50 RPM) TO MIN RPM FOR CELL 16 (1800)
BCS GETBLM2A
CMPA NTRPMX
BCS GETBLM4A BR IF RPM > LIMIT; THEN NEED TO CHANGE CELL
JMP LD176 IF ALL OK, THEN STAY IN CELL 16

************************************************** ****
* TEST FOR CONDITIONS TO REMAIN IN PT OPEN CELLS (17-19)
************************************************** ****
BLMPTCHKBRCLR MW1;BIT1,GETBLM4AIF CELL > 16 AND PT DELAY OVER, GO TO NORMAL BLM ROUTINE
… OTHERWISE IF DELAY NOT OVER
ANDB #3 …. RPMINDEX = BITS 0,1 OF BLMCELL
SUBB #1
LDX #KBLESB1A BLM CELL RPM BOUNDARY--LOW
ABX DETERMINE LOWER RPM BOUNDARY OF CURRENT BLCELL
TSTB IF RPMINDEX = 0, THERE IS NO LOWER BOUNDARY TO CHECK
BEQ GETBLM11
LDAA 0,X
SUBA KBLESHY SUBTRACT HYSTERESIS VALUE TO FORM LOWER RPM LIMIT
BCS GETBLM09
CMPA NTRPMX
BHI GETBLM4A BR IF RPM < LIMIT; CELL HAS CHANGED
GETBLM09CMPB #2 IF RPMINDEX = 2, THERE IS NO UPPER BOUNDARY TO CHECK
BEQ GETBLM2A
GETBLM11LDAA 1,X
ADDA KBLESHY ADD HYSTERESIS VALUE TO FORM UPPER RPM LIMIT
BCS LD176
CMPA NTRPMX
BCS GETBLM4B BR IF RPM > LIMIT; CELL HAS CHANGED
GETBLM2ABRA LD176

GETBLM4AJMP GETBLM4B

************************************************** ****
* TEST FOR CONDITIONS TO ENTER IDLE CELL (16)
************************************************** ****
BLIDLCHKLDAA NTPSLD IF CURRENT CELL <= 15, CHECK FOR IDLE STATE
CMPA KTPSBLML COMPARE CURRENT TPS WITH THRESHOLD (1.2%)
BHI GETBLM2B IF TPS > MIN GO CHECK PT STATUS
LDAA NTRPMX
CMPA KRPMBLML COMPARE CURRENT RPM WITH THRESHOLD (1800)
BHI GETBLM2B IF RPM > MIN GO CHECK PT STATUS
LDAB #16 IF TPS AND RPM BELOW LIMIT, USE CELL 16
JMP GETBLM60 GO STORE BLM CELL = 16

************************************************** ****
* NORMAL BLM ROUTINE BEGINS HERE
************************************************** ****
GETBLM2BBRSET MW1;BIT1,GETBLM4BBR IF PORT THROTTLE TO 2NDARY'S ON DELAY OVER

LDAB BLMCELL
ANDB #3 …. RPMINDEX = BITS 0,1 OF BLMCELL
LDX #KBLESB1A-1 BLM CELL RPM BOUNDARY--LOW
ABX DETERMINE LOWER RPM BOUNDARY OF CURRENT BLCELL
TSTB IF RPMINDEX = 0, THERE IS NO LOWER BOUNDARY TO CHECK
BEQ GETBLM15
LDAA 0,X
SUBA KBLESHY BLM RPM HYSTERESIS
BCS GETBLM10
CMPA NTRPMX
BHI GETBLM4B
GETBLM10CMPB #3
BEQ GETBLM20
GETBLM15LDAA 1,X
ADDA KBLESHY BLM RPM HYSTERESIS
BCS GETBLM20
CMPA NTRPMX
BCS GETBLM4B
GETBLM20LDAB BLMCELL
ANDB #12
LSRB
LSRB
LDX #KBLESB3 BLM CELL RPM BOUNDARY--HIGH
ABX
TSTB
BEQ GETBLM35
LDAA 0,X
SUBA KBLPMHYA BLM MAP HYSTERESIS
BCS GETBLM30
CMPA MAPSD
BHI GETBLM4B
GETBLM30CMPB #3
BEQ GETBLM36
GETBLM35LDAA 1,X
ADDA KBLPMHYA BLM MAP HYSTERESIS
BCS GETBLM36
CMPA MAPSD
BCS GETBLM4B
GETBLM36LDAB BLMCELL MAPINDEX = BITS 2,3 OF BLMCELL
BRA GETBLM60

************************************************** ****
* PT OPEN CELLS, ADJUST BASED ON RPM
************************************************** ****
GETBLM4BBSET MWFA;BIT2+BIT3 SET BLOCK LEARN UPDATE AND CELL CHANGE
LDAB #16
LDAA NTPSLD
CMPA KTPSBLML COMPARE TPS TO THRESHOLD (1.8%)
BHI GETBLM4C
LDAA NTRPMX
CMPA KRPMBLML COMPARE RPM TO THRESHOLD (1800)
BLS GETBLM60
GETBLM4CINCB IF TPS AND RPM ARE ABOVE IDLE LIMIT, INCR BLM TO NEXT CELL
BRCLR MW1;BIT1,GETBLM40IF PT DELAY IS NOT OVER, THEN GOTO NORMAL BL ROUTINE

LDAA NTRPMX
CMPA KBLESB2 BLM CELL RPM BOUNDARY--MID
BLS GETBLM60
INCB INCREMENT BL CELL IF RPM HIGHER THAN BOUNDARY
CMPA KBLESB3 BLM CELL RPM BOUNDARY--HIGH
BLS GETBLM60
INCB INCREMENT BL CELL IF RPM HIGHER THAN BOUNDARY
BRA GETBLM60

GETBLM40CLRB BLMCELL = 0
LDAA NTRPMX MODIFY BLM CELL LOCATION BASED ON RPM
CMPA KBLESB1A BLM CELL RPM BOUNDARY--LOW
BCS GETBLM50
INCB BLMCELL = BLMCELL + 1.0 (IN COLUMN 1)
CMPA KBLESB2 BLM CELL RPM BOUNDARY--MID
BCS GETBLM50
INCB
CMPA KBLESB3 BLM CELL RPM BOUNDARY--HIGH
BCS GETBLM50
INCB
GETBLM50LDAA MAPSD MODIFY BLM CELL LOCATION BASED ON MAP
CMPA KBLPMB1A BLM CELL MAP BOUNDARY--LOW
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
CMPA KBLPMB2A BLM CELL MAP BOUNDARY--MID
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
CMPA KBLPMB3A BLM CELL MAP BOUNDARY--HIGH
BCS GETBLM60
ADDB #4 BLMCELL = BLMCELL + 2.0
GETBLM60STAB BLMCELL STORE BLM CELL
LDX #LBLMM POINT TO LEFT BANK BLM CELLS
ABX BLMADD = BLMM + BLMCELL
LDAA 0,X
CMPA KBLMMAX IF BLM VALUE IS OUT OF RANGE, INDICATE
BHI GETBLM65 …NVRAM FAILURE AND INITIALIZE B/L TABLE
CMPA KBLMMIN
BCS GETBLM65
TSTA TEST LEFT BLM
BMI GETBLM85 LIMIT LEFT PE BLM TO 128 - BR IF ALREADY >= 128
BRCLR MWFA;BIT5,GETBLM85BR IF NOT IN PE

LDAA #128 IF IN PE USE LEFT BLM VALUE >= 128
GETBLM85STAA LBLM SAVE FINAL LEFT BLM
LDX #RBLMM POINT TO RIGHT BANK BLM CELLS
ABX BLMADD = BLMM + BLMCELL
LDAA 0,X
CMPA KBLMMAX IF BLM VALUE IS OUT OF RANGE, INDICATE
BHI GETBLM65 …NVRAM FAILURE AND INITIALIZE B/L TABLE
CMPA KBLMMIN
BCS GETBLM65
TSTA TEST RIGHT BLM
BMI GETBLM84 LIMIT RIGHT PE BLM TO 128 - BR IF ALREADY >= 128
BRCLR MWFA;BIT5,GETBLM84BR IF NOT IN PE

LDAA #128 IF IN PE USE RIGHT BLM VALUE >= 128
GETBLM84STAA RBLM SAVE FINAL RIGHT BLM
BRA GETBLMEX

GETBLM65BSET CLCCMW;BIT6 NV RAM FAILED FLAG = 1
LDAA #128
CLRB
LDX #32
BLMINITCSTAA LBLMM-1,X
DEX
BNE BLMINITC

STAA LBLM
STAA RBLM

GETBLMEXEQU *


Cool! I wasn't going insane then!;) Do you agree then that when using a bin like this that it is advantageous to allow the ecm to think that secondary opperation is normal in the interest of being able to use all fuel cells for improved driveability?
Scott

[tpepmeie]

Cool! I wasn't going insane then!;) Do you agree then that when using a bin like this that it is advantageous to allow the ecm to think that secondary opperation is normal in the interest of being able to use all fuel cells for improved driveability?
Scott

For me, if I were doing a calibration for a car w/ no secondaries & one of these 4 files, I would modify this routine to avoid the 3 PT open cells, and just use the normal 16-byte BLM table. That is, assuming I needed/wanted to use Block Learn at all.

[Maxlean]

For me, if I were doing a calibration for a car w/ no secondaries & one of these 4 files, I would modify this routine to avoid the 3 PT open cells, and just use the normal 16-byte BLM table. That is, assuming I needed/wanted to use Block Learn at all.

Do you have any speculation as to why these particular calibrations are like this? I'm sure GM had a reason for this mode of opperation. And am I to assume that you run an open loop tune normally?
Scott

[tpepmeie]

Do you have any speculation as to why these particular calibrations are like this? I'm sure GM had a reason for this mode of opperation. And am I to assume that you run an open loop tune normally?
Scott

Scott,
it makes good sense, actually. The fuel tables are different for PT open v. PT closed, so therefore it is logical that you would want the ability to apply a different long-term correction value to each case. One might say that would not be needed, since you'd likely be in Power enrichment under PT open conditions anyway. Not necessarily. Imagine the situation where you make a quick passing maneuver on the freeway, then quickly back off but not less than 4.7% TPS. The PTs would remain open until the TPS lower threshold is met, yet you'd easily be out of Power enrichment.

What I just can't grasp is why the seemingly random application of this enhanced BLM code. Why is it not, for example, in BFXB (one of the last service calibrations released)? For the most part, the later released cals are very similar in all other regards.

For me, I generally ran my 91 350/500hp in Open Loop. As long as you get the fuel tables very close to ideal, and run with consistent gas and ambient conditions, its not a problem. Its all a matter of preference, really. However, I did have it going on full-time closed loop dual Wideband O2 control for awhile, just to see if I could do it. :)

Todd