Question about PE fueling vs temp.

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Apr 26, 2003 | 07:35 PM

87_TA

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From: ELIZABETH,PA,USA

Question about PE fueling vs temp.

Hi all,
I have been trying to dial in my PE a/f ratio but notive that when coolnt temp is about 125-130 that my a/f ratio is about 12.2-12.5
But when coolant temp is higher like 140-160 then a/f ratio is about 13.0-13.3 .
Here is my F/A adder in Pe settings.
% added temp c
54.7 -40
48.8 -16
43.8 8
33.6 32
22.7 56
22.7 80
22.7 104
22.7 128
22.7 156
Hmmm wait-I Think I see the problem,The 32 celcious table must have control all the way untill 55 celcious which is 131 degrees.
Sorry bout that.

But I do have another Q.
Is there anyway to disable BLM influence on PE without disabling
closed loop corrections?

Apr 26, 2003 | 08:28 PM

RBob

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From: Chasing Electrons

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Transmission: check

Re: Question about PE fueling vs temp.

Quote:

Originally posted by 87_TA
Hi all,
.
.
.
But I do have another Q.
Is there anyway to disable BLM influence on PE without disabling
closed loop corrections?

I believe that it already does. Maskid $8D? Check the code between $C9AD & $C9B7. If in PE mode the BLM is set to 128.

RBob.

Apr 26, 2003 | 11:36 PM

87_TA

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From: ELIZABETH,PA,USA

Quote:

I believe that it already does. Maskid $8D? Check the code between $C9AD & $C9B7. If in PE mode the BLM is set to 128.

Thanks Rob,Yes BLM'S do go to 128 .
But I had always thought the ecm made correction,if noy\t thats great.

Now Im back with the same problem as earlier,I changed all the values in the F/A adder vs. coolant temp to the same value (22.7) and still the same.

First pass at wot coolant temp 127 and inj. pulsewidth 9.8-10.1
shortly after that coolant temp 135 and inj pulse width 8.9-9.1
WTH! how can I tune wot when this is happening?

Apr 26, 2003 | 11:48 PM

funstick

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From: great lakes

have you checked the

open loop chnage to a/f ratio vs collatn temp table to see if something is defeating you there ?

85.7
50.9
20.8
10.7
6.0
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9

stock table

or what about

open loop change to a/f ratio vs map ??

0.0
0.0
0.0
0.0
0.0
3.1
3.9
5.1
7.0
7.0
9.0
10.2
12.1
14.1
14.1
14.1
14.1

stock table

just some thougths. maybe youive got a few bad byte in your bin. import all your tables into a fresh binary see what happens.

Apr 27, 2003 | 12:26 AM

87_TA

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From: ELIZABETH,PA,USA

Well Rob,I think it must have influence because I just took it out and blm's were 140 just before and stayed there during WOT
and added about 9% to my PW.

Thanks funstick,yes I checked the open loop FA adder vs.temp
and all there past 8 degrees house the value.

Moving all tables to another bin is a good idea,I just noticed on this last bin that my speedo is jumping around like 50 mph...

Apr 27, 2003 | 08:39 AM

RBob

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From: Chasing Electrons

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Quote:

Originally posted by 87_TA
Well Rob,I think it must have influence because I just took it out and blm's were 140 just before and stayed there during WOT
and added about 9% to my PW.

You are correct, it does the traditional if BLM < 128 ignore it or if BLM > 128 use it.

If you would like to patch that out, go to $C9AB (virtual address) and overlay two bytes with a NOP ($01). The physical address (BIN) would be $C9AB - $8000 = $49AB. So at $49AB change the $2B to $01 and at $49AC change the $02 to $01. See the following (you are patching out the BMI at line 11402):

Code:

C9A7                     11396  ;-------------------------------
C9A7                     11397  ; SAVE UPDATED CURRENT BLM VAL
C9A7                     11398  ;-------------------------------
C9A7                     11399  
C9A7  D7 DF              11400  LC9A7:	STAB	L00DF 		; BLM CELL NUMS 0 - 7
C9A9  97 E0              11401  	STAA	L00E0		; SAVE BLM
C9AB  2B 02              11402  	BMI	LC9AF		; BRA IF BLM > 127 (adding fuel)
C9AD                     11403  
C9AD                     11404  ;-------------------------------
C9AD                     11405  ; 
C9AD                     11406  ; SET BLM = 128 IF IN PWR ENR
C9AD                     11407  ; 
C9AD                     11408  ;-------------------------------
C9AD                     11409  
C9AD  86 80              11410  	LDAA	#128		; MID VALUE
C9AF                     11411  				; 
C9AF  D6 46              11412  LC9AF:	LDAB	L0046 		; AFR MD WD
C9B1  C5 20              11413  	BITB	#$20		; B5 1 = IN PWR ENRICH
C9B3  27 02              11414  	BEQ	LC9B7		; BR IF not IN PWR ENRICH
C9B5                     11415  				; .... else
C9B5  97 E0              11416  	STAA	L00E0		; IF YES, SET BLM = 128

The only gotcha' would be if your current bin does NOT have those values to start with (the $2b & $02). From what I understand there are several versions of the $8D mask. There have been code changes made that have moved some of the code around.

If yours does not match you should be able to find the proper location to patch via the information above.

RBob.

Apr 27, 2003 | 09:52 AM

Grim Reaper

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From: The Bone Yard

Car: Death Mobile

Engine: 666 c.i.

Quote:

Originally posted by RBob
You are correct, it does the traditional if BLM < 128 ignore it or if BLM > 128 use it.

You know RBob, the significance of the above statment really just explains why so many guys experience noticeable improvements in their performance when they first start tuning their eprom.

Most people with our vintage of cars almost always notice that their calibration is too rich when they start tuning. GM apparently took the "conservative approach" and tended to make the calibration overly rich.

So when people start pulling out the excess fuel, they often will notice an increase in performance because they are now getting closer to an optimal AF Ratio. Better, GM put "safety code" in the calibration to ensure that if you are running lean.

Of course, one should properly tune the PE Tables with a WB O2 sensor after they have gotten all of their Part Throttle Tables optimized. But it again illustrates why a person is likely to experience an increase in performance when they start to optimize their eprom.

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Apr 27, 2003 | 09:14 PM

87_TA

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From: ELIZABETH,PA,USA

Thanks alot Rob,BUt I have one problem..
I have never disasembled code,Nor would I know the first thing to do. I just use generic tunercat and winbin tables.
If you were to point me in the right direction I would love to start
and think its about time I do.

Thanks again.

Apr 27, 2003 | 09:28 PM

Grim Reaper

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From: The Bone Yard

Car: Death Mobile

Engine: 666 c.i.

Check the "sticky" on Source Code. There are links in there to get ALL the info you need to start getting into Assembly Language. From there, just start posting specific questions - especially if you need to how an instruction works.

Trust me, there are a dozen other guys wanting to learn Assembly but afraid to ask. If you ever programmed a computer, you have big start.

Apr 27, 2003 | 11:47 PM

#10

87_TA

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From: ELIZABETH,PA,USA

Quote:

Thanks Glenn I will,and will be asking question as well

Ok guys I am still having problem with Temp influence on PE .
I just took a scan and made two back to back runs at wot.
with BLM's locked down.
One at 130 coolant temp and avg BPW was (8.30)
And another at 170 temp,avg. BPW was (7.65)
Heeeelp,where am I losing my 8%?
I have all the values in the PE F/A adder vs. coolant temp @ 22.7.
Please help, I will be glad to send somebody a scan file and a bin to see if they can see why..

Apr 28, 2003 | 01:38 AM

#11

funstick

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From: great lakes

Quote:

One at 130 coolant temp and avg BPW was (8.30)

whats your desired afr at 130 vs 170 ?? non pe ?

Apr 28, 2003 | 09:12 AM

#12

87_TA

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From: ELIZABETH,PA,USA

Here is the open loop vs. coolant temp.

85.7
51.0
20.9
10.7 -4
6.0 8
1.0 20 = 68 degrees
1.0 32
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0

Now in the constants there is a minimum temp for open loop fueling I have set to 45 or 113 degrees (f),maybe thats to close to 130 or something...

Apr 30, 2003 | 08:18 PM

#13

87_TA

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From: ELIZABETH,PA,USA

Anybody have anything to add to this? I can't believe that nobody out there spends time optimizing there PE ?
Grumpy I know you have something to add?

May 1, 2003 | 09:46 PM

#14

drive it

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From: Ca.

I've found that I havn't had to change the vs coolant...maybe I'm just lucky-but I've tuned with a wide band and the vs rpm, after warm up; anywhere from 160 to 220 deg it's so close (f/a ratio) as to not bother with the vs coolant. For lower temps I havn't logged a wide band run, always figured I wanted to let it warm up before wot. I'll have to go back thru the datalogs to check inj. pulse widths at diff temps....