Just as title says, helping brother-in-law with cammed LS1..
Not sure what is primary fuel source...
Do I scale the MAF tables or VE? Or both?

Also If I wanted to disable MAF, how would I go about that?

Have not been through the tables yet to see for my self, waiting for my own copy and cable.
If anyone did not know they are vin specific..

Thanks for any help.

 

As I understand it, the MAP code runs full time, and is used as a diagnostic sanity check for the MAF, due to an EPA requirement for OBII. Typically, your running on the MAF.

On the LT1 8051, there is just a flag to set to switch to MAP only mode.

 

Thanks Grumpy,
Thats what I was led to believe but wanted to hear it from your mouth.
I asked on ls1 tech, on the PCM board, I don't think many peolpe know. They must just change what people tell them.

 

Well after asking that question several more times on the LS1 board - guess what, no on can give me a straight answer.....
Some still say that both VE and MAF is used while others say VE is used only during Open Loop ( Yet still scale the whole table when making idle changes, meaning all kpa areas - amazing!
While others say VE is used during low air speeds and startup.

Which frustrates the heck out of me that all of these people are editing their PCM calibrations but don't know why.
Most of them seem to settle with the old global inj. constants change.
Hopefully once I get my hands on it I will be able to tell someone,
They have the tools - use them and see.

One gut on there scaled his whole VE by 50% and does not know now why his car has a hesitation! So somebody replied "thats too much, go 60% - 70%... based on what!!!!!!!!!!???????

 

Some of that is self-inflicted.
The flash stuff was turned into a cash cow. And now, a few are just milking it for all it's worth. The guys that contributed to the original flash effort have all been somewhat been betrayed, and as far as I know have all stopped participating in the DIY EFI world. The Flash stuff started out as a Freeware Tool, but that didn't last long. The archives at DIY-EFI will answer any doubter's guestions about the full story.

BTW, you might hunt some libraries and look at the differences from say a LT1 Caprice to LT FBody, with the 8051s to see what all they changed.

 

Thanks Grumpy,
I actually made some headway today.

It seems that the PCM uses VE as scaler with the MAF.
The VE is used on startup and below 4000 RPM. After 4000 RPM and anytime in PE mode it only uses MAF. Unless there should be a MAF failure than it relies souley on VE. Which is why I was trying to stress to them not to scale all load ranges of VE.

Kinda weird, those guys don't seem to drive around like us to get VE perfect.
Here is a thread to explain code better.

 

Gosh, that just makes so much sense.
If you been reading what I had to say about AE, and how it relates to PE, then this just lines up perfectly.
MAP for the transistional stuff, and MAF for high loads. I'd been thinking of a MAP/MAF hybreed, looks like it's already been done. Thou, I was thinking of doing a tad differently.

 

this make more sense with the stuff on the LT1 and not having a definitive AE function. MAF is great for steady load states. it however is horribale when dealing with 2 things

positive atmopshere and change in TP.

map has its draw backs as well.

As for the ls1 stuff. im gonna start playing here really soon and ill let you know what i find out.

 

Here is that link of code that I forgot to add to post..

http://www.hptuners.com/forum/YaBB.p...num=1078851555

edit: Darn spelling.

 

Wish I'd known that a few years ago.
Just get one of the bigger MAFs (or the ZO6), and redo the whole cal., to match.

 

I think the map is used at startup for baro readings. Not sure what else

Is there a public PCM hack or something?

 

Hey Tim,
Map is also used for fuel correction as stated above.
Also I added a link to some code explaining its use.

 

I'll check the code It's only a matter of time before my 86 t/a has an LS-1. So it's never too early to learn! I do know alot on the hardware and ecm functions

 

I like the ls1 stuff. I need to get my greasy mitts on one

 

I see that guy has some human friendly stuff of the algorithm posted. Kinda neat the way they juggle the maf and the map to do the calculations. I wonder how large the actual compiled code is in one of those PCMs. I imagine it would be something rediculus like 100,000 lines of code when disassembled.

 

I have ls1edit and use it on my vet(98) and no it is not global as in the 3rd gen cars at all.You will agree once you get the program yourself.There are 2 alternatives (afr/ maf) to addressing
what you are trying to accomplish and ls1edit is somewhat simpler. And btw When you do get it the scales are considerably smaller, hence make very small changes.

 

Thanks for reply,
We scaled the lower portion of VE. Worked great!