Code: EGR and CTS conversions

[jim_in_dorris]

what parameter name in tunerpro is coolant temp, I can't seem to find it. And if I minded, I wouldn't have worried about responding, this is like a timeout from work, it helps keep me sane. Oops, to late for that. LOL.

I am looking at the ALDL output stream, and it looks like the raw temp is at $0025. That is just what I think at the moment, may change as I work this out. The problem is that this is inverse. That is higher counts = cooler temps. I am not sure where the conversion takes place yet from counts to temp for the aldl stream.

LD4ED FDB $0025 ; 4. COOLANT
; see table 1

here is the ALDL table entry, it is the 4th data item.

FAFF DECB ; DECR DIAG MSG LINE COUNTER
FB00: ASLB
FB01: ABX ; ADJ ADDRESS INDEX
FB02: LDX 0,X ; GET ADDRESS FROM TABLE
FB04: LDAA 0,X ; GET VALUED FROM ADDRESS
FB06: LFB06 STAA L007C ; CURRENT DIAG OUTPUT VALUE

This is where it sticks the value in the ALDL stream. at FB02 when X =4, it will get $0025 from the ALDL table (LD4ED), then at FB04 it will get the value stored at $0025 which should be the coolant temp. However, I can't seem to find where the value in $0025 changes from counts to temp. It may already be in temp when it is stored. How $00E3 and $0025 relate is something I haven't figured out yet. Also trying to figure out exactly why 34/35 is the breaking point when you test.

[EagleMark]

And if I minded, I wouldn't have worried about responding, this is like a timeout from work, it helps keep me sane. Oops, to late for that. LOL.

I to find this way more relaxing then life in general!


Yes, this is where Coolant temp goes to ALDL, I am reading it in Data through TunerPro ADX called Coolant Temp. It's not in XDF as data...

 		;---------------------------------------------
    	;  ALDL XMIT TABLE OR ADDRESSE'S
    	; 127747 ECM
		;
		;  5.7L TBI    L05 C/K    87,91 TRUCKS
		;
    	; DATA PIN: Read data on PIN "E" of ALDL Connector
		;
		; BAUD RATE:  160 Baud
		;             Open 		- 20 Bytes
		;             10k  		- 20 Bytes
		;             Shorted 	- 20 Bytes
		;
		;---------------------------------------------
    	ORG $04E7	;
LD4E7   FDB $D002   ; 1.  EPROM ID LSB
LD4E9   FDB $D003   ; 2.  EPROM ID MSB
					;---------------------------------
LD4EB   FDB $00FD   ; 3.  CURRENT IAC POSIT, (0-255)
					;	  N = COUNTS
					;---------------------------------
LD4ED   FDB $0025   ; 4.  COOLANT
					;	  see table 1
					;---------------------------------

Coolant table 1 is about line 2438 in ASDU3.asm

 	;=============================================
		;
        ;	TABLE 1 --- COOLANT TEMPERATURE
		;
		;
        ;	 A/D          DEGREES
        ;	COUNTS           C
        ;	-------       -------
        ;	255            -40
        ;	251            -30
        ;	250            -25
        ;	247            -20
        ;	245            -15
        ;	241            -10
        ;	237            - 5
        ;	231              0
        ;	225              5
        ;	218             10
        ;	209             15
        ;	199             20
        ;	189             25
        ;	177             30
        ;	165             35
        ;	152             40
        ;	139             45
        ;	126             50
        ;  	114             55
        ;  	102             60
        ;  	92              65
        ;  	81              70
        ;  	72              75
        ;  	64              80
        ;  	56              85
        ;  	50              90
        ;  	44              95
        ;  	39             100
        ;  	34             105
        ;  	30             110
       	;   26             115
       	;   23             120
       	;   21             125
       	;   18             130
       	;   16             135
       	;   14             140
       	;   13             145
       	;   12             150
	   	;    0             200
		;
		;=============================================

Have you ever looked at ARJU_Hac.src ? It has a lot of stuff after the Prom.

[jim_in_dorris]

Okay mark, it looks like $0025 is raw counts, does the ADX do the conversion to temp? I still don't see how $0025 and $00E3 connect.

edit. I looked in TPV5, it does a lookup, so $0025 is raw counts and is somewhere around 52 or 53 counts for 88 c. This is right at 34/35 hex.. now if I can just tie $00E3 to $0025 I will know what is happening with the data.

[EagleMark]

I think it's just a start up coolant temp.

L00E3     EQU     $00E     ; START UP COOL

[jim_in_dorris]

L00E3 EQU $00E3 ; START UP COOL

And the only place that I find $00E3 referenced says start up cool when it loads, but it only gets stored here

: LDAA LD51F ; 50c,Coolant default, ERR 14/15
FDBA: LFDBA STAA L00E3 ; COOL, 1k pu

; Error 14/15 param
; Coolant default
;---------------------------------------------
LD51F FCB 126 ; 50c, 122f Coolant default

That would mean that it is comparing the EGR enable to 126 counts, 34/35 hex would not be close, as I explained above. and it would never change. It has nothing to with actual coolant temp.

here is what happens..


load accum with 132 (from D1B3) EGR parameters
compare 132 to 126 (from 00E3)
Branch if 132 less than 126. Nope won't branch.

Set D1B3 to 34 or 35 and it will branch. The part causing it to die is tied to actual coolant temp not here. I will venture to say that any value above 34 hex and below 7E will cause your truck to die and anything below 35 hex your truck will run. Now we need to find out why setting the EGR enable does that. How is it tied to actual coolant temp. I will keep exploring this.

[gregs78cam]

Okay mark, it looks like $0025 is raw counts, does the ADX do the conversion to temp? I still don't see how $0025 and $00E3 connect.

edit. I looked in TPV5, it does a lookup, so $0025 is raw counts and is somewhere around 52 or 53 counts for 88 c. This is right at 34/35 hex.. now if I can just tie $00E3 to $0025 I will know what is happening with the data.

That seems to make sense. The PCM stores and sees everything as a digital 'count', the ADX converts that to a real world value, and we can see it in HexEdit as a hexadecimal number. Mark if you were to change you view in HexEdit to decimal it should show the counts, which the ADX converts to *C.

[EagleMark]

I will venture to say that any value above 34 hex and below 7E will cause your truck to die and anything below 35 hex your truck will run.

Seems you found something very close to my test...

4. EGR CTS to enable 36h would die when revved up.
5. EGR CTS to enable 35h would run fine when revved up.

Mark if you were to change you view in HexEdit to decimal it should show the counts, which the ADX converts to *C.

That's what I started to do when I found this issue. Then found so many different conversions I had no idea what was going on? Half of which need no conversion! Some I have found to look sane and react exactly to hex, converted to decimal. Other's are way off and must go through the A/D counts and need the conversion.

EGR was another whole issue that started the temps conversion issue.

[jim_in_dorris]

I found it!!!! Coolant from $0025 (actually result from A/D) stored at E3 here

FD91: LFD91 PULA
FD92: CMPA LD51E ; 35c, COOLANT LOW LIMIT
FD95: BLS LFDBA

The PULA is get saved accum A value. I followed it from the A/D converter to here.

FDBA: LFDBA STAA L00E3 ; COOL, 1k pu and save it here. I now know how this works. E3 and 25 are the same thing so it makes sense. When coolant temp is 88 C the counts are 34/35 hex. everything fits. now to figure out why your truck dies.

[jim_in_dorris]

I will start looking at EGR stuff tomorrow after I finish a little paid work. I really think I am getting a handle on this. Mark please start making a list of questions about Coolant temp comments and I will try to resolve them as I can.

[EagleMark]

I know why it dies! It's because I set the "EGR CTS to enable 36h would die when revved up."

I know when it runs! It's because I set "EGR CTS to enable 35h would run fine when revved up. "

You just verified it in code! Give or take 1h for coolant temp at 88c and did have 1c variable in tests.



OK Back to serious... why would turning on/off EGR Enable temp there even matter while parked and rev engine up? Would barley hit 1000 RPM and seemed to shut off fuel? Async flag came on at same time as it started to die... Dam, I should have watched what BPW was doing at the same time!

[jim_in_dorris]

Also, this comment is WRONG

CMPA LD51E ; 35c, COOLANT LOW LIMIT

It should be -35c.

No Mark, we know that setting those values causes it to die, not why it dies. Thats what I intend to figure out next.

[EagleMark]

I will start looking at EGR stuff tomorrow after I finish a little paid work. I really think I am getting a handle on this. Mark please start making a list of questions about Coolant temp comments and I will try to resolve them as I can.

Well here's one we can consider accurate.

Edited Findings Closed loop entry at cold start LD299 :
1. Tests were done on fresh ADSU chip read from my factory ECM, in a factory ADSU vehicle while emulating with AutoProm.
2. Closed loop was entered at 69c when warming up.
3. Closed loop Enable Temp is 40h with no conversion is 64c
4. Add in 2 timers that add up to over a minute and I did have engine at 1200-1500 RPM for the warm up... so I believe 64c is accurate.

Change would be:
LD299 FCB 64 ; 64c COOL Min for CLS LP Enable
it is
LD299 FCB 64 ; 18c COOL Min for CLS LP Enable

Could double check with this?
2. Tests were all done warmed up and data showed 88c as Coolant temp. Varied up/down by 1c throughout tests.
3. Closed loop was entered at 91h
4. Closed Loop was exited at 94h
Conclusion: Conversion could be figured out that 91 to 94h = 88c.

[1project2many]

Mark,

I wanted to double check this before replying just to make sure it's correct.

Within the ecm there are "pull up" resistors which are used to create a bias voltage on the temp sensor line. The temp sensor then pulls this voltage back to ground. The voltage is read by the A/D converter and associated with a temp reading. However, not all ecm's are the same in this regard. The 7747 uses a single fixed 1k pull up resistor to create a single bias voltage. You'll see the references "1k p/u" in some of the disassemblies. But other ecm's use a dual pullup resistor circuit and the ecm is able to choose which resistor to use. This apparently allows better resolution across the temperature range. The resistors used are 348 and 4k Ohms. For these ecm's you're likely to see a very different A/D --> Temp conversion chart. In addition to this, the IAT sensor may also have a fixed pull up resistor of 2.5k Ohms which would lead to another A/D conversion table.

In summary, be careful if hopping from one disassembly to another looking at temp conversion charts because different ecm's will probably have different charts.

[jim_in_dorris]

1project, what ECMs are we talking about? I think mostly right now we are concentrating on the 7747 with $42 but if other ECM/Dissassemblys are used, it would help to know which ones.

[EagleMark]

This whole thread is 1227747 $42 for now.

The others I looked at were $4E, $4F and I forget, but all the same C3 type ECM, none of which had IAT. All of them had similar conversions but again different, most were in this range:
0.572900 * X + 0.000000
0.546875 * X
0.588235 * X + 0.000000
0.625000 * X + -5.000000

When it looks like now they did not need a conversion at all? Well some, that is the porpose now to decifer which is which. Besides the EGR issue.

All good information though Shannen, it will help as I persue some of these others. As always I appreciate your expertise and time to help us!