it's scary what can be found in an ECM

[Joesixpack]

Okay, I'm done arguing with Oneshortofasixpack, as his own quote shows he's a FUGGIN' TARD and can't read!

Go across just the friggin 150mm3 value on the chart. WHAT THE FUGG do you see?

Look at it Cheapsixpack....fuggin' look!....The EXACT SAME VOLUME OF FUEL IS INJECTED 7 TIMES! You know what it based on? PRESSURE AND DURATION FOR THAT INJECTOR! PRESSURE AND DURATION EQUAL A SPECIFIC INJECTED QUANTITY.

This is an example of ONE...FUGGIN' ONE...set of injectors.

At a given pressure and a given pulsewidth, you get a SPECIFIC VOLUME OF FUEL INJECTED GIVEN THAT PARTICULAR SIZE OF INJECTOR.

If this specific set of injectors was run at 140 MPa for 3000 uS, what would the INJECTED fuel volume be? ALMOST 450 mm3/stroke!

If this specific injector was used and we applied your retarded azz theory to it, we'd have no reason to apply more than 1000 uS of duration at 140 MPa to run the truck at the same power as a stock truck. And that's not the case.

That's it! That's the last I'm arguing with your azz.

It's one thing to be stubborn, it's a whole 'nother to be stump dumb.

LMFAO still no clue.......LOL

 

[TheBigNasty]

I'm no mathematician but....seems to me that the table posted (fuel commanded mm3 vs. fuel pressure commanded) states that for x psi and y mm3 you need to hold the injector open for the value in the corresponding cell.

So, what I gather here is that you change the cell. The computer says, "for y amount of fuel at x amount of pressure my tune states I should open this long". I still thinks its getting y mm3 of fuel at x amount of pressure, but in fact it's getting a completely different volume.

 

[Cummin-a-long]

LMFAO still no clue.......LOL

*bdh*

You're a fuggin' moron.

If it makes ya happy, scale it up to 450mm3....it's IRRELEVANT.

 

[Cummin-a-long]

So, what I gather here is that you change the cell. The computer says, "for y amount of fuel at x amount of pressure my tune states I should open this long". I still thinks its getting y mm3 of fuel at x amount of pressure, but in fact it's getting a completely different volume.

The ECM has no idea how much fuel is being injected.

All it knows is I'm being told to provide THIS much pressure and hold the injector open for THIS long. The mm3 value is the REFERENCE for those variables.

If I stick a stock injector in and did that, I'd get one volume delivered.

If I stick a 200 over injector in there and don't change a DAMN THING in the tune, what would happen? I'd get a totally different volume of fuel and the ECM wouldn't have a clue.

 

[zstroken]

The ECM has no idea how much fuel is being injected.

All it knows is I'm being told to provide THIS much pressure and hold the injector open for THIS long.

If I stick a stock injector in and did that, I'd get one volume delivered.

If I stick a 200 over injector in there and don't change a DAMN THING in the tune, what would happen? I'd get a totally different volume of fuel and the ECM wouldn't have a clue.

If you followed the scaling and modified all of the tables would the value being commanded be close? It might be a pain since every injector and/or CP3 change would require new scaling.

Just asking as I don't know what all tables are available.

 

[Cummin-a-long]

If you followed the scaling and modified all of the tables would the value being commanded be close? It might be a pain since every injector and/or CP3 change would require new scaling.

Just asking as I don't know what all tables are available.

You could, and it wouldn't hurt anything.

If you have the flow data for your injectors and you want it accurately reflected as the reference, you could do that.

Like in the chart above, if you knew you only wanted to run a max of 24000 psi (165 MPA) and you could scale the reference to 450mm3 and then it would reflect the true volume.

But, the ECM doesn't care. It only sees mm3 as it relates to the pedal position, it applies that to all these charts and when push comes to shove, it applies a given pressure for a given duration and THAT equals the volume of fuel injected.

If you took a stock injector and used the same scale (450mm3), the ECM wouldn't care, but you likely would not be injecting enough fuel for the truck to run because your duration and pressure values were based on that much larger injector.

Can you scale it like that? Sure! Knock yourself out, it just means that for every truck you are tuning, you'd have to have the injector flow data and you'd have to scale every single axis, in every single tune to reflect accordingly.

 

[duck_04]

Everything Rich is saying makes sense, and he can elaborate on it, instead of just saying "you have no clue". I'm still curious where the volume sensor is.

 

[TheBigNasty]

So how do you start from zeros and modify? You just throw in numbers that sound good, data log, then adjust? Then if your pump keeps up....good, if not....increase duty cycle and repeat?

 

[Cummin-a-long]

The ECM only does this.

It takes THIS map....which you can set any way you'd like. If 1 - 100 is easier for you to digest, then you can do that.

And applies the specified mm3 value to these tables....

And what you get is the volume of fuel that THAT individual injector can flow.

Doesn't matter if it's a stock injector or a 200 over, all it knows is that at that reference value, you're telling me to apply THIS pressure for THIS long.

 

[Joesixpack]

Looks like you're finally admiting this "reference" is to FUEL VOLUME........LOL

Now lets see if you can explain what this 129mm3 is on the side of the valve cover......It can't possibly be fuel volume could it........

 

[Cummin-a-long]

[FONT=&quot]

So how do you start from zeros and modify? You just throw in numbers that sound good, data log, then adjust? Then if your pump keeps up....good, if not....increase duty cycle and repeat?

[/FONT]
[FONT=&quot]
[/FONT][FONT=&quot]If you just start with it and you really don't know the values and what will make the truck run, you really have to data log it....or do a SH!T ton of math to figure out what you need.[/FONT]
[FONT=&quot]
[/FONT][FONT=&quot]One thing you can do is use the custom mapping feature and see what the truck is ACTUALLY doing and you can start from there.[/FONT][FONT=&quot]
[/FONT]
[FONT=&quot]

[/FONT]
[FONT=&quot]
[/FONT][FONT=&quot]Once you have the values that make the truck at least idle correctly, you can start applying your values to achieve the end goal.[/FONT]
[FONT=&quot]
[/FONT][FONT=&quot]What I do is I pick specific points on the maps and I apply the target value that I want at that point, then I build the tune around those points, because I'll tell ya flat out that if you use the OEM maps, a full 1/3 of it will never be used because it's not in any real world range that will actually be applied.[/FONT]
[FONT=&quot]
[/FONT][FONT=&quot]Once you tune a crap load of trucks, you have tunes that are a CLOSE fit and then all you're doing is fine tuning it for THAT specific owners wants.[/FONT]

[FONT=&quot]If he wants it totally clean and not a lick of smoke, you go in one direction. If he wants a light haze so it's a slight over fuel condition, you go another way. If he wants enough fuel to spray the crap out of the truck, you do something else.[/FONT]
[FONT=&quot]
BUT, if the truck is properly fueled and has the correct airflow, the tables will actually be pretty similar.[/FONT]

 

[Cummin-a-long]

Looks like you're finally admiting this "reference" is to FUEL VOLUME........LOL

Now lets see if you can explain what this 129mm3 is on the side of the valve cover......It can't possibly be fuel volume could it........

Sure, if ya like.

Now, toss a set of 100 hp injectors in the truck and let me know what changes in the value.

I bet the valve cover still says 129mm3. I bet the tune still says that too. But that's NOT what is now being injected.

:doh:

 

[Cummin-a-long]

Better yet, don't change the injectors.

Just change the rail pressure to 26k psi instead of 23,209.

What happens?

The valve cover still says 129mm3. The tune still says 129mm3. But the fuel quantity is NOT 129mm3.

Here let's try it again....

Leave the truck bone stock, but increase the duration at 129mm3.

What happens?

The valve cover says 129mm3. The tune says 129mm3. But the injected quantity is not 129mm3.

The ECM doesn't give a rats azz. All it knows is THIS pressure, for THIS long, at THIS reference point.

The quantity of fuel is NOT dependant on that reference.

 

[Joesixpack]

The ECM only does this.

It takes THIS map....which you can set any way you'd like. If 1 - 100 is easier for you to digest, then you can do that.

And applies the specified mm3 value to these tables....

And what you get is the volume of fuel that THAT individual injector can flow.

Doesn't matter if it's a stock injector or a 200 over, all it knows is that at that reference value, you're telling me to apply THIS pressure for THIS long.

Your comming along so great and I dont want to hurt your progress, BUT.......

THE ECM is coming to the injector conversion table WITH a VOLUME of fuel it wants, that table OUTPUTS .....(TIME).

Your getting there.........


No cigar on the 129mm3's.

 

[Cummin-a-long]

:nail:
*bdh*
:banghead:

 

[TheBigNasty]

Or this....looks pretty similar, right.

This one is commanding max pressure all the way down to 1600 RPM's and ZERO throttle.

This is why you have to bump the truck down into neutral to get it to stop hanging the throttle.

Going back to the original argument, you say the table is to blame for rail hang. You claim, "This is why you have to bump the truck down into neutral to get it to stop hanging the throttle."

In more recent posts you claim mm3 is nothing more than the ecm's interpolation of tps %.

Say we are at 3000 rpm at the far left column. It's in the red, maxed out. "rail hang" area. What does removing the load have to do with slowing the engine down, getting out of "rail hang" and back into the green.

 

[triton]

the difference here just seems to be terminology. I'm sure Rich knows damn well the definition for mm3's can be cubic millimeters in volume. What JSP needs to get, or not.... is that in these tables we're working with, apparently the mm3 value is only a reference and not to be taken as flow volume.

 

[Scooter's Roofing]

Everything Rich is saying makes sense, and he can elaborate on it, instead of just saying "you have no clue". I'm still curious where the volume sensor is.

this

 

[LReiff]

Everything Rich is saying makes sense, and he can elaborate on it, instead of just saying "you have no clue". I'm still curious where the volume sensor is.

If what Rich is saying makes sense then tell us why Cummins put a value in the tuning software that EfiLive translated as "mm3" that some think is not directly related to fuel flow?

The tune is built around this parameter. You run out of fuel flow volume the engine loses power. You build the tune to reflect a loss of fuel flow by lowering the numerical value of this parameter and the engine responds the same as it would if fuel flow volume were restricted. A well built tune will have the mm3 parameter adjusted to match the fuel flow volume of the components on the motor.

 

[Big Swole]

Somewhere out there, Wade and Greg H are smiling and laughing.
Cause this is the worst internet war In a while that didn't involve them two. lol



Carry on...