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Discussion Starter · #1 ·
The pulse time tables for the main injection only go to 100 mm3 requested. Has anyone tried modifying the Throttle Base Injection table to request more than 100 mm3? This would be off the pulse time table. Will it extrapolate past 100, or use the pulsetime for 100 for any request past 100?
 

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Discussion Starter · #3 ·
That tells me it uses the 100mm3 pulsetime for requests over 100 mm3. For later versions, would it be possible to change the axes cells for the tables...so I can give it pulsetimes for fueling requests over 100 mm3?

I want over 100 for more power. Right now, the technique is to fudge the pulsetime tables to get more fuel without "requesting" over 100. I'd like to do it explicitly. So the torque calc remains valid, and the trans stays sane. Also, the MPG calc would remain accurate (or as accurate as stock).
 

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I have a 75 hp tune from a tuner that turned the throttle based injection up to 166mm. So this does not make any difference in power? Only Injection pulse widths? Why is the throttle based injection PID even there if it does not change anything in the pulse width time?
 

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Discussion Starter · #5 ·
The pulse width (time) determines how much fuel is shot in...in conjunction with fuel pressure. So the pulse time table takes the desired amount, and pressure, and tells the ECU how long to hold the injector open, to get that desired fuel amount....pretty simple.

The problem is, the table to look up pulse times, only goes to 100 mm3. So if I reset the throttle table to request 120 mm3 (for more power), how does the pulsetime get looked up (the table only goes to 100)? Will it use the time corresponding to 100 mm3, and therefore only inject 100 mm3....or will it extrapolate past 100 at the slope between 90 and 100, thereby giving a pulsetime longer than the pulsetime for 100mm3? I'd like it to extrapolate, obviously, but not having tried it, I was hoping someone else already has.

I don't want to request 120 and only get 100.
 

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You will find that if you go over 100 it will look up the cell that is valued at the 100 on the Main Injection Table.

You can set it to 120, 150, 190 it will change nothing.

If you want to prove it out, log the tune, then make the change over 100 and relog it, at WOT you won't see any changes.

;)
 

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Thanks for the replies guys someday I will get this thing figured out
All you need is a 500 or 600 hours of playing with the tables, logging and failing miserably like I did and you will begin to figure it out too.....:cool:

Once you figure out the basics it will get easier to make a change and have it do what you want it to do,

Good Luck,

T:D NY
 

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cit1991, one of our beta testers did a controlled experiment setting the main pulse time at 100mm3 to 1800µs (from memory). Then commanded numbers above 100mm3 in the throttle table....guess what, the injector on time never went beyond 1800µs. Notice any stock GM file will not command beyond 100mm3, most only go up to 95mm3.

There is indeed a hard coded limiter in the code before the pulse lookup table that will limit it to 100mm3, it has to or else the ECM will be looking for values beyond that table.

So, someone observed that an aftermarket tune goes way beyond 100mm3, perhaps they know something we all don't, but right now, looking at log files and the code in the ECM I can't explain why this would serve any purpose, though it 'might' help with the MPG calc.

It has already been suggested that we extend the tables beyond 100mm3 so you don't need to fudge the pulse widths as that would indeed be the correct way to do things. If we do this it will be in the form of a DSP² update as there is some pretty major code changes to do such things.

Cheers,
Ross

P.S - cit1991, well spotted!
 

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So, someone observed that an aftermarket tune goes way beyond 100mm3, perhaps they know something we all don't, but right now, looking at log files and the code in the ECM I can't explain why this would serve any purpose, though it 'might' help with the MPG calc.

I didn't see that on a data log I was just looking at the tune. Also the new programer that has the program on the fly function ( I won't mention wich one on here) if you try to read the pcm, in every tune it will flash the stock one back to efi live. Confusing huh:confused: ):h
 

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Also the new programer that has the program on the fly function ( I won't mention wich one on here) if you try to read the pcm, in every tune it will flash the stock one back to efi live. Confusing huh:confused: ):h
Well, I'm confused, I have no idea what you are talking about!.

Cheers,
Ross
 

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Discussion Starter · #12 ·
cit1991, one of our beta testers did a controlled experiment setting the main pulse time at 100mm3 to 1800µs (from memory). Then commanded numbers above 100mm3 in the throttle table....guess what, the injector on time never went beyond 1800µs. Notice any stock GM file will not command beyond 100mm3, most only go up to 95mm3.

There is indeed a hard coded limiter in the code before the pulse lookup table that will limit it to 100mm3, it has to or else the ECM will be looking for values beyond that table.

So, someone observed that an aftermarket tune goes way beyond 100mm3, perhaps they know something we all don't, but right now, looking at log files and the code in the ECM I can't explain why this would serve any purpose, though it 'might' help with the MPG calc.

It has already been suggested that we extend the tables beyond 100mm3 so you don't need to fudge the pulse widths as that would indeed be the correct way to do things. If we do this it will be in the form of a DSP² update as there is some pretty major code changes to do such things.

Cheers,
Ross

P.S - cit1991, well spotted!
Damn. A clear and concise answer, and exactly what I was afraid of.
 
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