it's scary what can be found in an ECM

I know this is all a lot deeper than a quick explanation and I may be out in left field but, ok..... I know you don't want it 1:1 So, say your cmded is asking for 50% but, the actual only showing 10%. Would we prefer the PID to say be at 10%-/10%+ to the cmded.... more, less ??
 
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If you get it close, great!

I'll tell ya flat out, I don't waste a lot of time on the duty cycle UNLESS I see commanded and actual duty cycle matching AND I see my rail pressure not meeting what I want.

In that case, you need to raise the duty cycle.

I look at the FCA's duty cycle like this. Let's say you have to drive 50 miles...do you need a full tank of fuel to drive 50 miles? No, but it doesn't hurt anything to have a full tank of fuel.

Remember, if you see ACTUAL duty cycle lower than COMMANDED and the truck isn't bucking, lurching, or otherwise showing poor driving characteristics, then the PID is doing what it's suppose to....mainly that would be the (D) function slowing that rise in duty cycle so that you get the soft landing vs the crash landing.
 
so if your tune is set up right and you have all your bases covered you shouldnt have to touch the pid controls . Is this right ?
 
chance cobb said:
so if your tune is set up right and you have all your bases covered you shouldnt have to touch the pid controls . Is this right ?
Click to expand...

Mmmmmm.....not really. What you shouldn't have to touch, if the truck is properly fueled and turbo'd is the FCA duty cycle.

What tends to happen is the OEM PID tends to be a little too aggressive with trucks that are heavy on the fuel is you'll notice it in the cruise control first. The truck will surge slowly at first (like a boat on the waves) and then it gets more frequent and intense, to the point that you'll turn the cruise contol off.

Reducing the (P) functions and increasing the (I) functions will smooth this out. Reducing the (D) functions will also reduce the rate pressure climbs and can help prevent the overshoot.

But, there are 100 ways to skin the cat. You can change the ramp rate of the rail pressure; you can keep timing the same in your cruising ranges; you can reduce the change in duration in those areas, etc....there's a ton of way to achieve the goal.
 
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Cummin-a-long said:
In this table DO NOT look at mm3's as a PHYSICAL VOLUME, that's not what it is. It's actually more closely related to throttle position that anything else.

In a stock map, the value is 0 - 140 mm3's. This is simply a reference that NUMEROUS functions rely on.

You ARE NOT asking, for example, 25 cubic millimeters of fuel. What you're doing is telling the ECM that I'm at THIS throttle position.

Example, I'm at 2000 RPM's and I'm commanding 55mm3's of fuel. This results in 20993 psi of pressure being commanded.

NOW, this DOES NOT equate to a specific VOLUME of fuel injected, because what have I still not added?.....DURATION. Once I add duration, now I get a specific volume of fuel that is actually injected. Until we add duration, all I've done is told the fuel system to pressurize the resevoir to 20993 psi. Without a duration table, that pressure goes no where.
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*bdh* For the love of god man,

It absolutely IS FUEL VOLUME IN mm3 :nail:.

When the ecm is commanding 140mm3's your driving point is at the extreme right of the table.

If your going to put on a clinic get it right for gods sake.


For the last time the ecm works in fuel volume, maybe its not so obvious in efi as it is hacked and you don't get to see all the little stuff that makes it obvious. BUT I guaranphuckentee it does. IT commands a fuel volume, goes to the injector conversion chart and derives a injector duration for a given pressure setpoint.
 
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And, here we go again.

We can scale that mm3 value to ANYTHING we like. It's value IS A REFERENCE, that's all.

If you're gonna run your suck, at least understand the software and what you can and can't do with it. If I want those values set at 0 - 14 instead of 0 - 140, I can set them that way. IT's A REFERENCE POINT AND A REFERENCE POINT ONLY!

You got any thing intelligent to add or are just intent on running your suck and ****tin' up the thread some more?
 
Cummin-a-long said:
And, here we go again.

We can scale that mm3 value to ANYTHING we like. It's value IS A REFERENCE, that's all.

If you're gonna run your suck, at least understand the software and what you can and can't do with it. If I want those values set at 0 - 14 instead of 0 - 140, I can set them that way. IT's A REFERENCE POINT AND A REFERENCE POINT ONLY!

You got any thing intelligent to add or are just intent on running your suck and ****tin' up the thread some more?
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If it is a reference, why are their units attached to it?
 
Okay, I'm gonna break this down crayola style for those wearing hockey helmets and drool cups....

Here is the main duration table in an OEM tune. If you notice the mm3 value it goes from 0 - 140. This is a stock table.

Slide2-23.jpg


Here is a table that I've simply changed the REFERENCE VALUE for the mm3's. All this means is I have to also change this value in my throttle position and the rest of the table that use this REFERENCE VALUE!

Slide1-25.jpg


Do ya see anything there home cheese?....IT's A FRIGGIN REFERENCE POINT!
 
IT is still in complete relation to VOLUME OF FUEL......*bdh* I don't care how you scale it, it is FUEL VOLUME.

When the ecm is commanding X of fuel at Y RPM here is our pressure set point.
 
And here we have the throttle.

The first one is the stock table and the second one has been changed so the REFERENCE VALUE matches what's in the main duration tables.

Again, do you see the REFERENCE VALUE?....it's not a PHYSICAL VOLUME!

Slide1-29.jpg


Slide2-30.jpg
 
Joesixpack said:
IT is still in complete relation to VOLUME OF FUEL......*bdh* I don't care how you scale it, it is FUEL VOLUME.

When the ecm is commanding X of fuel at Y RPM here is our pressure set point.
Click to expand...


Wow....just friggin wow!

Even when it's broken down RIGHT IN FRONT OF YOUR FACE, you're too damn stubborn to see it.

Like I said yesterday....whatever makes you happy chief, you roll with it.
 
Cummin-a-long said:
Okay, I'm gonna break this down crayola style for those wearing hockey helmets and drool cups....

Here is the main duration table in an OEM tune. If you notice the mm3 value it goes from 0 - 140. This is a stock table.

Slide2-23.jpg


Here is a table that I've simply changed the REFERENCE VALUE for the mm3's. All this means is I have to also change this value in my throttle position and the rest of the table that use this REFERENCE VALUE!

Slide1-25.jpg


Do ya see anything there home cheese?....IT's A FRIGGIN REFERENCE POINT!
Click to expand...

No point made. Go through the whole tune and cut all the mm3 related axis back so that min to max range matches and you'll have effectively cut fuel delivery back so far that the engine will not run!
 
You gonna try and tell everyone that at 2000 RPM's and full throttle that I'm not commanding the EXACT SAME DURATION AND PRESSURE VALUES?.....

If you're gonna raise your hand in someones clinic, KNOW THE FRIGGIN MATERIAL.
 
Funny not EVEN ONE other tuner is backing the chit your pumping out, I've watched them poke there heads in here and not a even a peep.

Clinic......LMFAO.....

For the last time your precious "reference value" is exactly fuel volume whether you want to believe it or not. Don't even care any more.
 
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Joesixpack said:
It absolutely IS FUEL VOLUME IN mm3 :nail:.

When the ecm is commanding 140mm3's your driving point is at the extreme right of the table.

If your going to put on a clinic get it right for gods sake.


For the last time the ecm works in fuel volume, maybe its not so obvious in efi as it is hacked and you don't get to see all the little stuff that makes it obvious. BUT I guaranphuckentee it does. IT commands a fuel volume, goes to the injector conversion chart and derives a injector duration for a given pressure setpoint.
Click to expand...


I hope you are not implying that it works in actual cubic millmeters of fuel.

This is duramax crap, but here's the explaination in one of the throttle based fuel quantity tables:

This table defines the base fuel injection quantity based on throttle position if the user selected EFILive DSP5 program #1 is running.
The value from this table (which is defined as mm3/st) is then used by the main fueling table as the fuel quantity that is to be delivered.
For example, if the value read from this table was 70mm3, then the main fueling tables {B0720} "Main Injection Pulse" and {B0721} "Main Injection Pulse (No Pilot)" will use 70mm3 as the reference to the Y axis of the table.


Now, yes it does say volume. It also says reference. I know for a fact that you can change the amount of fuel injected by changing duration at the SAME MM^3 value in the tune. You go to the tables that reference MM^3 and pulsewidth and increase the pulse width. This does change the actual volume of fuel delivered. It does not have anything to do with MM^3 in a literal sense. Otherwise you'd need twice as much mm^3 on a race truck as a daily driver. Not the case.

Maybe I'm misunderstading what you are saying, but you can not take the MM^3 as a literal value.
 
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