100mm3 limit LB7/LLY for delphi ECM

[malibu795]

here is the thread that i particpated in back in feb 07
http://www.dieselplace.com/forum/showthread.php?t=136760&highlight=125mm3 im going to try and get the main stuff the thread is 3 pages long
original quetion

If the ECM does not acknowledge fuel over 100 mm3, why do the boost tables all go to 125 mm3.

ross's replies

Good point, to know the real answer to that we would need to ask the software team at GM (like they would tell you anyway!)

There are many stange things, for example, we limit the pulse times to 5000uS, the ECM can actually calculate out to 32767uS (insane!).

It may have even been a situation where a different programmer was working on the boost control code and he decided to make he's table go up to 125, 130mm3. Or, that boost routine is used on another ECM that will go out to 130mm3.

Cheers,
Ross

My point was that what you see in EFILive does not mean that is the limits of the ECM. Technically we could have allowed users to enter pulse times of 32767uS, but, limiting the table values to more sensible limits means we don't get to read of someones disastrous test results of using a 32767us pulse.

Another example is the main fuel pulse table axis for the mm3 values, there is actually two almost seperate mm3 lookups, one scaled 0,1,2,3......7,8,9 then other 10,20,30,40....90,100, they simply do a nice 10 step table lookup, and depending on if it is looking at 0-10 or 10 - 100 they scale the mm3 value differently. When you look at the maths it just works out nicer to have 10 entry points, they could have made it 10 to 1000mm3 if they wanted to, but, remember, GM wrote all this for a stock truck. 100m3 was going to be plenty of room.

my question

Originally Posted by Flashscan;1595652;
Good point, to know the real answer to that we would need to ask the software team at GM (like they would tell you anyway!)

There are many stange things, for example, we limit the pulse times to 5000uS, the ECM can actually calculate out to 32767uS (insane!).

It may have even been a situation where a different programmer was working on the boost control code and he decided to make he's table go up to 125, 130mm3. Or, that boost routine is used on another ECM that will go out to 130mm3.

Cheers,
Ross

here is a question i can command up to 200mm3 on my tbiq but both the b0720 and b0721 tables only go to 100mm3???
my max injection quality warm is 120mm3 max is 200mm3
my current tune i logged 105mm3 with 157mpa with 1950uS????? i would liek to know were that calculatin came from.....i aksed a couple other memebers.. i dont think i was able to convey the info correctly


adam

ross's replay to my question

Adam, here's the rather technical explanation on how the mm3 values are used on B0720 & B0721 and this will hopefully make some people think about how things are done.

I'm going to use just the 10 - 100mm3 values as an example. (schulte will like this I'm sure).

To get the lookup value the ECM does this process.
Gets the currently commanded mm3
Scales it to suit the table lookup routine
Gets pulse value based on the mm3 value (and RP).
Now the maths behind that (easily seen in the assembly code).......

Assume 10mm3
10mm3 in hex = $8280 (these are signed numbers)
Multiply by $100 = $828000
Divide by $280 = $3433
Add $CBCD = $10000
Now, just take the word value to get the correct mm3 cell to use, in this case that = $0000, so, use cell 0
Some more examples -

Assume 50mm3
50mm3 in hex = $8C80 (these are signed numbers)
Multiply by $100 = $8C8000
Divide by $280 = $3833
Add $CBCD = $10400
Now, just take the word value to get the correct mm3 cell to use, in this case that = $0400, so, use cell 4

Assume 90mm3
90mm3 in hex = $9680 (these are signed numbers)
Multiply by $100 = $968000
Divide by $280 = $3C33
Add $CBCD = $10800
Now, just take the word value to get the correct mm3 cell to use, in this case that = $0800, so, use cell 8

Now, this is where it gets interesting, if you command over 100mm3 looks what happens......

Assume 130mm3
130mm3 in hex = $A080 (these are signed numbers)
Multiply by $100 = $A08000
Divide by $280 = $4033
Add $CBCD = $10C00
Now, just take the word value to get the correct mm3 cell to use, in this case that = $0C00, so, use cell 12.
BUT, there is no cell 12, so what GM have done is to put a check in this part of the code that if the commanded mm3 scaled result is above $0900 (see below) then that is what it will be limited to or else the ECM would attempt to look at a value outside of the table.
FYI, the final example -
100mm3 in hex = $9900 (these are signed numbers)
Multiply by $100 = $990000
Divide by $280 = $3D33
Add $CBCD = $10900
Now, just take the word value to get the correct mm3 cell to use, in this case that = $0900, so, use cell 9.
So, looking at table B0720, count how many mm3 cells there are from 10mm3 to 100mm3 (start the count at 0, not 1), you will find 100mm3 is cell count #9.
So hopefully you can see from all the above, any commanded mm3 value above 100mm3 will still result in the ECM using the pulse time in this table from the 100mm3 row.

For those that can read CPU32 assembler, here is the exact code that does the above scaling -

move.l d7,d5 ; Move Commanded mm3 into d5
lsl.l #8,d5 ; Multiply by 256 ($100)
divu.l #$280,d5 ; Divide by 640
add.w #$CBCD,d5 ; Add 52173
move.w #$900,d7 ; Table cell count limit value (9)
cmp.w d7,d5 ; Compare to scaled mm3 value
bcs.s loc_30B4E ; Skip next if less than, Else...
move.w d7,d5 ; Set mm3 look up value max to cell #9

Cheers,
Ross

john kennedy's remark to Ross post

The example Ross gave just shows how EASY it is with EFI Live.

I do at least know from experience that commanding over 100mm3 is fruitless...

shultes reply to kennedys post

Originally Posted by Kennedy;1596255;

The example Ross gave just shows how EASY it is with EFI Live.

I do at least know from experience that commanding over 100mm3 is fruitless...

Ross's post explains why this is true. In short, GM's error checking prevents commands over 100mm^3 from producing any difference in operation than commanding 100mm^3- there are only 10 cells (addressed 0-9), so anything over 100 would theoretically refer to a cell that doesn't exist (if there was no error handling).

my post

Originally Posted by Kennedy;1596255;


The example Ross gave just shows how EASY it is with EFI Live.

I do at least know from experience that commanding over 100mm3 is fruitless...

Posted by schulte;1596281;
Ross's post explains why this is true. In short, GM's error checking prevents commands over 100mm^3 from producing any difference in operation than commanding 100mm^3- there are only 10 cells (addressed 0-9), so anything over 100 would theoretically refer to a cell that doesn't exist (if there was no error handling).

yet i have a log saying i got more than 100mm3.....105mm3 to be exact

i was just asking how.......

ross's reply to my post

Oh I see, the ECM will still internally process values higher than 100mm3 as your saw on the scanner, however, what I tried to show was that although the ECM might be working with the figure of 105mm3, or even 200mm3, it also limits these values internally based on the way the table is set up it needs commanded mm3 values for. So what you see on the scanner is correct, but for some tables the ECM ignores values above the set limits.

Cheers,
Ross

i dont know how the bosch ECM work with soemthing above 100mm3. i do know all the tables run to 120mm3
but for the 01-05 dmaxs the limit is 100mm3 that you can control.
hope this make sense for some people

 

[Mike]

here is the thread that i particpated in back in feb 07
http://www.dieselplace.com/forum/showthread.php?t=136760&highlight=125mm3 im going to try and get the main stuff the thread is 3 pages long
original quetion

ross's replies


my question

ross's replay to my question

john kennedy's remark to Ross post


shultes reply to kennedys post

my post


ross's reply to my post


i dont know how the bosch ECM work with soemthing above 100mm3. i do know all the tables run to 120mm3
but for the 01-05 dmaxs the limit is 100mm3 that you can control.
hope this make sense for some people

Perfect sense for a particular table. Thanks for the post.

 

[malibu795]

and which table is that mike?

 

[Mike]

and which table is that mike?

The tables that max out with a reference not past 100mm3.

 

[malibu795]

currenlty on LLY and LB7
all base torque tables max @ 100mm3
all main injection pulse tables max @ 100mm3
all pilot injection pulse tables max @ 100mm3


you can not control anything past theses limits on the current setup..


maybe im not following what you are trying to say....

 

[McRat]

mm3 are only reference for convenience. We really want pressure and duration.

If you find a limit to either, you have a problem that needs work.

On any of the race tunes, a command for 100mm is a command for over 200mm of true fuel delivery.

 

[malibu795]

i know the diff between command flow and actually flow....

i will get a guy that ask hey im a noobie can you give me some pointers?

first table i look at is the TBIQ... ussualy i will see mm3 numbers between 105-200mm3 on the top end..
combined with what ross said and my log that i did a year ago.. i commanded 100mm3+ and got pulse width that wasnt any were close to what i wanted on the main inj pulse tables. bassicly lead me to believe commanding anything aboe 100mm3 was a crap shoot to what timeing and pulse width you were getting. IMO that is not a good thing.

since feb 07 i havent writen a tune commanding more than 100mm..
thats JMHO

 

[Mike]

currenlty on LLY and LB7
all base torque tables max @ 100mm3
all main injection pulse tables max @ 100mm3
all pilot injection pulse tables max @ 100mm3


you can not control anything past theses limits on the current setup..


maybe im not following what you are trying to say....

I just said it makes sense when a table is referenced to 100mm3. But with say tliq. A reference higher has helped with eliminating defuel. Simon and I worked on this last year. That's all.

As Pat said, duration and pressure determine actual mm3 through an injector. Reported is only a calculation not actual. Better yet, reported is a reflection of Tbiq.

No mountain making going on here.

 

[malibu795]

if commanding mm3 is maxed at 100 why command more than 101? on tliq?

 

[Mike]

i know the diff between command flow and actually flow....

i will get a guy that ask hey im a noobie can you give me some pointers?

first table i look at is the TBIQ... ussualy i will see mm3 numbers between 105-200mm3 on the top end..
combined with what ross said and my log that i did a year ago.. i commanded 100mm3+ and got pulse width that wasnt any were close to what i wanted on the main inj pulse tables. bassicly lead me to believe commanding anything aboe 100mm3 was a crap shoot to what timeing and pulse width you were getting. IMO that is not a good thing.

since feb 07 i havent writen a tune commanding more than 100mm..
thats JMHO

FWIW, I have played in different aspects of tuning as well as some of which you have mentioned. Tuning as I did at that time, pw followed actual pressure unless actual was so low that commanded rail could not be sustained.

One more point. Following timing tables, ones that go to over 100mm3, timing references are taken for rpm and quantity higher than 100mm3.

 

[Mike]

if commanding mm3 is maxed at 100 why command more than 101? on tliq?

As stated before, defuel.

One more interesting find. By manipulating tables, a quantity over say 50mm3 can be useless. If pw and pressure are commanding a 3500ms pw and pressure is maxed out at say your limit of say 180mpa, no reference past this is needed unless rail pressure above this number is actually obtained.

 

[SmokeShow]

I feel like I just picked up a book written in German or something. I haven't the slightest idea what is going on. All I got was that 100mm3 is all that can be "seen" in the tuning yet more than that can be achieved somehow. I didn't follow how to, if it's possible, to do this in a controlled manner.

Crazy.

 

[malibu795]

making the TLIQ more and in sense over powering the base tq table you get a rough hard shift.

the key is to have them close together. if not then it wound be a smooth transistion.

but if commanding more then 101mm3 in the tliq when max fule commanded is 100mm3 works for you.. im glad.

IMO bottom line is if you tliq table and base torque table aren copesetice with each other you will have funky shift maybe not at wot but you will have them aon part throttle shifts

 

[Mike]

making the TLIQ more and in sense over powering the base tq table you get a rough hard shift.

the key is to have them close together. if not then it wound be a smooth transistion.

but if commanding more then 101mm3 in the tliq when max fule commanded is 100mm3 works for you.. im glad.

IMO bottom line is if you tliq table and base torque table aren copesetice with each other you will have funky shift maybe not at wot but you will have them aon part throttle shifts

Just saying there is more than one way to build a house. I don't push a technique, I only support techniques I can explain. Here, I am trying to understand this one and was only saying I need to research and draw my conclusion. Thanks

 

[malibu795]

i agree more then one way to skin a cat.

but when it come from the program producer (aka ross and paul) and they say what they said in the above posts that 101mm3 commanded dosnt work on a lb7/lly delphi ecm........ is like john kennedy said pointless


building a house without a foundation is pointless. IMO :hug:

 

[Mike]

i agree more then one way to skin a cat.

but when it come from the program producer (aka ross and paul) and they say what they said in the above posts that 101mm3 commanded dosnt work on a lb7/lly delphi ecm........ is like john kennedy said pointless


building a house without a foundation is pointless. IMO :hug:

Go back and read what has been posted above. You'll see how to build a house even without a foundation.

 

[McRat]

I command over 100mm to cover "interpolation"

You will notice that values jump from cell to cell. Often what will happen is a computer will take two neighboring cells to "guess" at a value. So if WOT is 98% measured pedal position, and you've programmed 90% = 90mm, and 100% = 100mm, you will get 98mm of fuel. By putting 110mm in there instead of 100mm, it might guarantee you will get 100mm instead of 98mm.

I'm not expecting the engine to fuel 110mm. I'm just hedging my bets.

 

[malibu795]

i run 90% thottle row the same as 100% throttle rows

 

[JoshH]

I command over 100mm to cover "interpolation"

You will notice that values jump from cell to cell. Often what will happen is a computer will take two neighboring cells to "guess" at a value. So if WOT is 98% measured pedal position, and you've programmed 90% = 90mm, and 100% = 100mm, you will get 98mm of fuel. By putting 110mm in there instead of 100mm, it might guarantee you will get 100mm instead of 98mm.

I'm not expecting the engine to fuel 110mm. I'm just hedging my bets.

I do the same thing. At 100% throttle I command 125 mm3 (LBZ ECM), but that's just because I want to make sure it injects the full 120 mm3 amount.

 

[Mike]

i run 90% thottle row the same as 100% throttle rows

So now there is not a reason to press the pedal to the floor.