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Thread: Code: EGR and CTS conversions

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    Code: EGR and CTS conversions

    Thought I'd take advantage of this thread for learning purposes. Can't seem to track what issue is.

    Here's the problem, EGR Temp enable is not working right in $42 mask/XDF.

    LD1B3 FCB 120 ; ..c COOL FOR EGR ENABLE (1K PU) TBL 3
    Can't find a table 3 and not sure what 1K PU is. There is a table for Coolant temp AD counts to C which I am used to using.

    XDF parameter title.
    EGR - Coolant Temp for EGR On!
    Here's the conversion from XDF.
    0.750000 * X + -40.000000

    Stock ASDU is 59c/84 hex Is this sane? Does EGR wait till 59C to operate?

    Raising it to max 151.xx C does not turn it off?
    Lowering it to -40C does turn it off?

    What's wrong? Should it be a Disable and not enable?

    EDIT: Looking at some other CTS to Enable conversions are:
    0.750000 * X -40.000000 NOTICE NOT + -40.000000
    0.572900 * X + 0.000000
    0.546875 * X

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    1K PU is referring to the A/D circuit using a 1K resistor to "pull up" the circuit to 5 volts. usually coolant temp is done through either a 348 or 4K(combined) resistor set, increases resolution. it looks like in the C3 era, GM only used a single 1K resistor to compromise between the two(check sheet3 of the Ludis schematics for the 7747).

    i'm looking at the code that involves it(starting at EB59), that value is compared to 00E3, it branches to EBA5 if the calibration value is lower, where EGR DC% is set to 0. i'm seeing 00E3 being referred to as startup coolant temp in some locations as well. it only ever gets stored to at FDBA.
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    Mark, that is a puzzler. I only looked at it for a minute, will spend some time tonight but that address is not referenced anywhere else in the code. It appears to not be used. also my ASDU has 132 at that location. It must be in the second chip. I was posting at the same time as robert, looks like he found something. I will try tonight to puzzle out what egr is doing.
    Last edited by jim_in_dorris; 03-16-2013 at 09:56 PM.
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    Quote Originally Posted by EagleMark View Post
    EDIT: Looking at some other CTS to Enable conversions are:
    0.750000 * X -40.000000 NOTICE NOT + -40.000000
    0.572900 * X + 0.000000
    0.546875 * X
    the first one is fine since the order of operations will do the multiply, then subtract.

    the other two.... looks like someone was guessing at the correct conversion, they shouldn't look like that. when dealing with delta, you'll have X*.75(for *C, if *F, X*1.35), but for all others, it should be the X*.75-40 you're used to.
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    Quote Originally Posted by jim_in_dorris View Post
    Mark, that is a puzzler. I only looked at it for a minute, will spend some time tonight but that address is not referenced anywhere else in the code. It appears to not be used. also my ASDU has 132 at that location. It must be in the second chip. I was posting at the same time as robert, looks like he found something. I will try tonight to puzzle out what egr is doing.
    Well unless my stock ASDU is compromised? I have 84h at that location which is 132d...

    Truthfully I don't even know if it's EGR? I've always used another way to turn off EGR and worked well. This time I used it and set to max. engine would idle but not rev up? Turn it down and engine would rev up and run fine.

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    Quote Originally Posted by RobertISaar View Post
    the first one is fine since the order of operations will do the multiply, then subtract.

    the other two.... looks like someone was guessing at the correct conversion, they shouldn't look like that. when dealing with delta, you'll have X*.75(for *C, if *F, X*1.35), but for all others, it should be the X*.75-40 you're used to.
    As to not confuse Jim, I am know using the ASDX3 ASM and ASDX BCC to work on my $42 XDF...

    Robert: Well back to your guess of guessing... may be it. What would be correct way to convert hex to decimal that represents temp in C without AD lookup?

    I've found several variations of
    0.572900 * X + 0.000000
    0.546875 * X
    0.588235 * X + 0.000000
    all over the place. None of which come out to temps in Jims ASM. Some are close?

    Like
    LD299 FCB 48 ; 25c COOL Min for CLS LP Enable
    0.546875 * X + 0.000000 Comes out to 26.26C

    Hex shows 30 which is 48d

    EDIT: Did find another old xdf that had conversion for above at
    0.625000 * X + -5.000000 which comes out to 25c in Jims ASDX3.asm file...

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    trying to calibrate using raw A/D counts is a horrible idea... you wouldn't be able to give it an equation or even convert it accurately at all since tunerpro doesn't support lookup tables in the XDF.
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    So everywhere I find these...?

    0.572900 * X + 0.000000
    0.546875 * X
    0.588235 * X + 0.000000
    0.546875 * X + 0.000000

    Should be... ?
    0.750000 * X -40.000000

    Then just use whatever came stock value and wing it up or down?

    Besides AD counts I Also found some reference to Inverse AD counts, no wonder there's so many conversions? No wonder this has always confused me...

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    Quote Originally Posted by RobertISaar View Post
    trying to calibrate using raw A/D counts is a horrible idea... you wouldn't be able to give it an equation or even convert it accurately at all since tunerpro doesn't support lookup tables in the XDF.
    Wondering how the ASM comes up with the value? Seems to be there and everyone just shot for a conversion that came close?

    LD299 FCB 48 ; 25c COOL Min for CLS LP Enable

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    I have wonderd about this before. But, according to a hac that I just looked at, the coolant temp calc (if indeed linear) should be a range of 192*C that is proportional to 256 A/D counts. Which would be the "0.750000 * X -40.000000" equation. Any parameter that references Coolant temp in *C should also be converted as such.
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    Quote Originally Posted by EagleMark View Post
    So everywhere I find these...?

    0.572900 * X + 0.000000
    0.546875 * X
    0.588235 * X + 0.000000
    0.546875 * X + 0.000000

    Should be... ?
    0.750000 * X -40.000000

    Then just use whatever came stock value and wing it up or down?

    Besides AD counts I Also found some reference to Inverse AD counts, no wonder there's so many conversions? No wonder this has always confused me...
    probably. this is one of the reasons why i don't like C3s.... too much stuff going on that is redundant in and already very limited enviroment.
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    Quote Originally Posted by gregs78cam View Post
    I have wonderd about this before. But, according to a hac that I just looked at, the coolant temp calc (if indeed linear) should be a range of 192*C that is proportional to 256 A/D counts. Which would be the "0.750000 * X -40.000000" equation. Any parameter that references Coolant temp in *C should also be converted as such.
    Hmmm... well I wonder? Since the A/D counts to Degrees C I have goes from
    255 = -40
    and
    0 = 200

    If that should not be 0.781250 * X -40.00000 ?

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    Fuel Injected! gregs78cam's Avatar
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    all coolant tables I saw were from -40 to 152C = 192*C range
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    1981 Camaro Z-28 Clone, T-Tops, 350/TH350
    1981 Camaro Berlinetta, V-6, 3spd
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    I guess it's splitting hairs at this point? But your the one who got me started on math, math is cool, it's everwhere! Yeah well how come it's not exact?

    Found this in a $0D dis.asm

    Code:
    ;>Coolant counts conversion table for raw A/D value
    ;
    ;	 A/D 	degrees		A/D
    ; 	counts     C		Inv
    ; 	------- -------		---
    ; 	255	    -40		  0
    ; 	251	    -30		  4
    ; 	250	    -25		  5
    ; 	247	    -20		  8
    ; 	245	    -15		 10
    ; 	241	    -10		 14
    ; 	237	    - 5		 18
    ; 	231	      0		 24
    ; 	225	      5		 30
    ; 	218	     10		 37
    ; 	209	     15		 46
    ; 	199	     20		 56
    ; 	189	     25		 66
    ; 	177	     30		 78
    ; 	165	     35		 90
    ; 	152	     40		103
    ; 	139	     45		116
    ; 	126	     50		129
    ; 	114	     55		141
    ; 	102	     60		153
    ; 	92	     65		163
    ; 	81	     70		174
    ; 	72	     75		183
    ; 	64	     80		191
    ; 	56	     85		199
    ; 	50	     90		205
    ; 	44	     95		211
    ; 	39	    100		216
    ; 	34	    105		221
    ; 	30	    110		225
    ; 	26	    115		229
    ; 	23	    120		232
    ; 	21	    125		234
    ; 	18	    130		237
    ; 	16	    135		239
    ; 	14	    140		241
    ; 	13	    145		242
    ; 	12	    150		243
    ; 	0	    200		255
    ;
    ;>Temp conversion for stored linear counts
    ; -Deg C = .746 x counts - 40
    SO if it were needing inverse would it be 0.750000 * X +200.000000

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    And this in a ASDX1.asm

    Code:
    					; INV COOL BP'S
    					;		17 lns	
    					;		BIN		Deg c
    					;		----------------
    					;		0           -5 
    					;		16 	5 
    					;		32 	15 
    					;		48 	25 
    					;		64 	35 
    					;		80 	45 
    					;		96 	55 
    					;		112 	65 
    					;		128 	75 
    					;		144 	85 
    					;		160 	95 
    					;		176 	100 
    					;		192 	105 
    					;		208 	110 
    					;		224 	115 
    					;		240 	200 
    					;		256 	201

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