it's scary what can be found in an ECM
- Thread starter triton
- Start date
Cummin-a-long
Big Angry
Lemme help you out with that Ty....
This is the tune in question.
As you can see, as low as 1600 RPM's and as little as half throttle, the rail pressure is MAX'd the fugg out.....this is rail hang.
This is the tune in question.
As you can see, as low as 1600 RPM's and as little as half throttle, the rail pressure is MAX'd the fugg out.....this is rail hang.
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Cummin-a-long
Big Angry
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.
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.
SHughes
Too much is never enough!
This is the first thread regarding EFI Live I have looked at. It's not something I have a need for, so I usually ignore it. So I clearly have no idea what an EFI tune should look like on a diesel, but I have played with EFI tuning on a few gassers, And WOW, these look terrible!!! even to my untrained eye.
I ditched the VP for a P7100, simply because I didn't like the idea of blindly tuning with a box I didn't really know what was doing. These CR's now scare the crap out me!!!! If I was to buy one, the FIRST mod would be EFI live!!!!!!
I ditched the VP for a P7100, simply because I didn't like the idea of blindly tuning with a box I didn't really know what was doing. These CR's now scare the crap out me!!!! If I was to buy one, the FIRST mod would be EFI live!!!!!!
duck_04
resident quack
My truck does this a lot...
In my limited experience throttle hang from extreme rail pressure happens happen like I'm about to explain. You've got the pedal all the way on the floor and commanded mm3 is way up pulling the commanded rp value from the lower right part of the table pictured. The next thing that normally happens...rpm is maxed out, somewhere around 3200-3500 and the flag man shuts you down. You lift off the throttle fast and if its a manual truck you slam the clutch pedal down to keep the motor from stalling which magnifies the result of rp hang because now there is no load to bring rpm back. At this point the rp value is all the way in the lower left corner of the table. RPM is still up and commanded mm3 is 0 but the motor continues to rev because rp is still up and the injector solenoids are only a one direction electronically controlled...this allows rp to over ride ecm command and the injectors continue to inject fuel. To eliminate this problem you must enter 0 in the lower left corner of the rp table and then smooth toward the upper right corner until you get the desired effect. All the tables posted in this thread will have throttle hang including the stock table. Dyno tuning will most likely never bring this out like an actual sled pull will.
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Joesixpack
Pull'n it.
That 36k is as meaningless as 99k in any cell you want at the limit period.
You can't possibly be putting out tunes without a limiter?
Whats in the pressure table has ZERO to do with throttle hang. The PID for pressure/volume control is where its at for controlling pressure overshoot.
triton
Scarlet Fever
this isn't the point of this post though. It also isn't about anything Rich did to a tune. The point that was made is.... it's a good thing the limiters were still in place. Either purposely left that way ( I would hope ) or who ever wrote it didn't have access to them.
When someone loads a box tune like this, if that's what it was..... you're at the mercy of what you can't see. I'd bet that anyone you showed that table wouldn't just say...... that value doesn't mean a thing and load it. It's a RED flag right off the bat whether it will go there or not.
Cummin-a-long
Big Angry
The PID controller only comes into play to correct errors over or under the commanded rate.
In this case, the PID controller is not the issue.
When you have the cruise control applied and the truck is surging, thats the PID controller being set too aggressively.
Rail hang is 100% due to these tables, NOT the PID controller.
The PID's sole function is to correct errors between commanded and actual pressure. If the pressure being commanded doesn't come down (i.e. the values in these tables) it isn't trying to correct anything, because the pressure is withing the range being commanded.
This isnt a PID issue.
In this case, the PID controller is not the issue.
When you have the cruise control applied and the truck is surging, thats the PID controller being set too aggressively.
Rail hang is 100% due to these tables, NOT the PID controller.
The PID's sole function is to correct errors between commanded and actual pressure. If the pressure being commanded doesn't come down (i.e. the values in these tables) it isn't trying to correct anything, because the pressure is withing the range being commanded.
This isnt a PID issue.
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JasonCzerak
New member
huh. interesting read guys. Those tables don't look like a smart way of doing things.
Joesixpack
Pull'n it.
LMFAO....The WHOLE table could be 24000 PSI if you wanted....THE PID that controls pressure is EVERYTHING to due with keeping it there.....:nail: wow.
Cummin-a-long
Big Angry
Aa for the limiters, limiters are there to protect the system.
Setting a limiter over 11k PSI below what you're commanding isn't protecting the system, its simply not knowing its there.
Correct use of the limiter would be setting it 500 psi OVER your target goal, not 11k psi below it.
Setting a limiter over 11k PSI below what you're commanding isn't protecting the system, its simply not knowing its there.
Correct use of the limiter would be setting it 500 psi OVER your target goal, not 11k psi below it.
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Cummin-a-long
Big Angry
You are correct, the PID controllers ONLY responsibility is maintaining commanded pressure......COMMANDED pressure.
If that pressure is not withing the ranges that you have the PID controller set, it makes corrections instantly, over time and on the next occurance.
Thats ALL it does, corrects errors between commanded and actual values.
That's all it does.
If you command 24000 psi, its gonna try and make 24000 psi....until you run into a limiter.
This is not a case of the PID controller. Your truck surging under constant throttle is an example of a PID error.
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Cummin-a-long
Big Angry
I tell ya what, lets do this.....
When the tuning for the 03 - 05's is released, I'll make ya 2 tunes.
One, with a table that looks like this and a totally stock PID controller and I'll do another with NOTHING changed EXCEPT, I'll put the LIMITER at 40,000 psi. Not the PID controller, the LIMITER. No other changes.
Wanna load it on your truck and see what happens?
When the tuning for the 03 - 05's is released, I'll make ya 2 tunes.
One, with a table that looks like this and a totally stock PID controller and I'll do another with NOTHING changed EXCEPT, I'll put the LIMITER at 40,000 psi. Not the PID controller, the LIMITER. No other changes.
Wanna load it on your truck and see what happens?
Joesixpack
Pull'n it.
What are you talking about PID limiter????
The PID's function is to meet commanded pressure AND VOLUME. Since we do not have a separate pressure control valve and a volume control valve, pressure control is VIA a volume control valve know as the FCA.
The pressure control PID is absolutely responsible for keeping pressure and volume inline with commanded.
Your not suggesting anything are you......
Why in the hell would you every run at stock PID with anything other than a stock tune stock injectors stock single pump? AND why the hell would you put the limiter at 40K.....:nail:
The PID's function is to meet commanded pressure AND VOLUME. Since we do not have a separate pressure control valve and a volume control valve, pressure control is VIA a volume control valve know as the FCA.
The pressure control PID is absolutely responsible for keeping pressure and volume inline with commanded.
Your not suggesting anything are you......
Why in the hell would you every run at stock PID with anything other than a stock tune stock injectors stock single pump? AND why the hell would you put the limiter at 40K.....:nail:
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Cummin-a-long
Big Angry
We're saying the same thing.
The ECM has no concept of volume. It only knows PRESSURE and TIME.
The FCA does not work on volume, it is simply acting in response to two things, 1 - what you are asking, and 2 - what is actually happening at the rail.
The FCA duty cycle is adjusted to maintain that pressure in the rail. It has has NO CONCEPT of volume.
The PID controller does ONE THING and ONE THING ONLY.....makes corrections to adjust to variation in commanded and actual pressure.
So, when your rail pressure map is COMMANDING 24,000 psi, but the pressure is actually 25,000 psi, what's it gonna do? It's going to attempt to bring that pressure down. Same thing if it's the other way around.
Now, If you're COMMANDING 36,000 psi and the ACTUAL pressure is at 23,000 psi, what is the PID controller going to do? It's going to attempt to bring that pressure up to 36,000 psi.
Preventing it from going that high is the limiter, which is either 23,205 psi in the OEM tune or whatever you decide to set it to.
The ECM has no concept of volume. It only knows PRESSURE and TIME.
The FCA does not work on volume, it is simply acting in response to two things, 1 - what you are asking, and 2 - what is actually happening at the rail.
The FCA duty cycle is adjusted to maintain that pressure in the rail. It has has NO CONCEPT of volume.
The PID controller does ONE THING and ONE THING ONLY.....makes corrections to adjust to variation in commanded and actual pressure.
So, when your rail pressure map is COMMANDING 24,000 psi, but the pressure is actually 25,000 psi, what's it gonna do? It's going to attempt to bring that pressure down. Same thing if it's the other way around.
Now, If you're COMMANDING 36,000 psi and the ACTUAL pressure is at 23,000 psi, what is the PID controller going to do? It's going to attempt to bring that pressure up to 36,000 psi.
Preventing it from going that high is the limiter, which is either 23,205 psi in the OEM tune or whatever you decide to set it to.
Joesixpack
Pull'n it.
Oh GAWD....the FCA is a VOLUME control valve....thats all it knows! The PID is never going to command higher than what is set in the LIMITER!
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Cummin-a-long
Big Angry
The FCA is 100% in REACTION mode. All it does is REACT to what it's told by the ECM, based on feedback from the rail pressure sensor.
What happens when you unplug the FCA and run the motor? The pressure goes to MAX, right. Does volume? NO, it has NO CONCEPT of volume.
SHOW ME WHAT MEASURES VOLUME? Show me the parameter that measures and controls VOLUME. There isn't one. The FCA is a valve, that's all it is. It has a duty cycle and nothing else.
I'm gonna make this as simple as possible. Look below at the picture, you'll see a few things. 1 - You see the LIMITER (23,208 psi) for commanded pressure. THAT is the parameter that dictates that no matter what you put in the table, the pressure is not allowed to go higher than that, 2 - You see the P.I.D. functions....look closely....large, small, positive and negative ERRORS. When the rail pressure hits that limiter, YES, the PID controller is what keeps it in check, BASED ON THAT VALUE. If I change that values to 40,000 psi, what's gonna happen?.....You guessed it, pressure is gonna come up until something gives.
What happens when you unplug the FCA and run the motor? The pressure goes to MAX, right. Does volume? NO, it has NO CONCEPT of volume.
SHOW ME WHAT MEASURES VOLUME? Show me the parameter that measures and controls VOLUME. There isn't one. The FCA is a valve, that's all it is. It has a duty cycle and nothing else.
I'm gonna make this as simple as possible. Look below at the picture, you'll see a few things. 1 - You see the LIMITER (23,208 psi) for commanded pressure. THAT is the parameter that dictates that no matter what you put in the table, the pressure is not allowed to go higher than that, 2 - You see the P.I.D. functions....look closely....large, small, positive and negative ERRORS. When the rail pressure hits that limiter, YES, the PID controller is what keeps it in check, BASED ON THAT VALUE. If I change that values to 40,000 psi, what's gonna happen?.....You guessed it, pressure is gonna come up until something gives.