Bruce this is for you.

in the $58 code at adress $334 there is a A/F mode switch. It can be either switched to evrv or injector constant. The question of weather this actually works ?? i dunno havent tried it but ill make a point of it soon. the switch mask is $80

enjoy.

 

Fun, I am beginning to wonder if GM hasn't released different versions of the $58 mask (as they have with other masks). The reason I bring this up is that the Sy/Ty & Sunbird code that I have worked with do not use either the injector constant or the bit you show above.

Are you at liberty to let us/me know the source of your information? Even access to the bin that you are examing would be enough.

RBob.

 

Is this the block your referring too? specifically bit 2?

 

i am at liberty to say whatever i want now. I sort of got burned but they still didnt learn what they needed to learn. LOL. more on that later.

yes bit 2 is the one im reffering to. i have not had the time to research it very far but from my reading of the P4 turbo pdf and a breif glance at the branches it might just enable the injector constant. i think that would also change the egr table to become some sort of inverse lookup as well. i know it will modify the BPW so how it all falls together ?? i dont know.

just trying to foster a bit more functionality out of it.

 

I think it is more to do with making fuel adjustments for EGR being part of the equation (ON/OFF) than triggering another routine ei Injector constant.

It looks like $0334 (KAFOPT3_2) enables/disables the EVRV (electronic vacuum regulator valve).

I would run it up on my bench, but I have sold all my running benches.. including mine.. lol Just need to solder/wire another one up. Just ordered parts today for 2 more. <G>

 

as i have stated im not sure if and how it works. havent had time to look into it. im being honest here. it just happened to catch my eye and sort of looked at it. it would appear that it enable the BPW and injector constant to work instead of using the EGR table for BPW. thats the jist of it. yet again i have not had time to reasearch this fully. i was simply replying to a comment i made earlier.

 

no problem.. I'm not busting your *****...

I don't see any reference to injector constant. All I see is referred to as injector flow rate.

$0x0328 (KDISFS) Injector Flow Rate in gal/hr.

But my understanding is that it has little effect overall.

cheers, BW

 

Just off the top,
isn't the inj/cons at 327?.
If so then just use find and see where it's referenced to in the code. If it's not called out in the code, it ain't ever going to be used. If it's referenced in the code then you need to comment that part of the code to see what it's being used for.

Just a guess.

 

I see what you are saying. The value at $328 is an injector flow rate (as opposed to an injector constant). However it still isn't used anywhere. The $334, bit 2 option is to switch between a PWM (or digital?) EGR and a vacuum controlled on/off EGR.

Dependent upon the type of EGR the actual EGR flow is calculated differently. One thing to what for we searching for the use of a cal term is the use of the X or Y register as an index. Very easy to hide the use of a cal term.

RBob.

 

it could very well be the hack ive been working from is in fact wrong. my understadning of the a/f word mode was that the set the stage for what gets used exactly. i have often pondered weather or not the inj/cons was simply put there by the engineers as a foot note of sorts. i understand is has no effect but there could be a peice of code somewhere in the ecm the turns it on. just tha same as the 2bar map sensor.

 

The GN code ('7148) also has a cal term (maybe two?) that is not used. GM puts together a mask from a library of routines. It can then be modified for a particular use. As the library pulls in everything, then a coder removes a piece of functionality, remnants can remain.

The hard part is figuring out whether it is really used or not. I've worked on code that used the X reg to index many bytes into the cal terms. I had to sit there with a calculator to find which term was being accessed. Almost wrote a program to do it for me. . .

RBob.