Throttle hang?

OS just means operating system. The Dodge Cummins have several different ones as does other makes/modles. Different truck configurations have different OS.

Jake
 
chizwizdiz said:
This, and on hard acceleration while driving. If you let off of the throttle, it will continue to pull for a second or two.
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I thought so. What I found most disturbing was this 03 seemed to increase in RPM's for that second then would SLOWLY come back down to idle. After driving it there was no comparison to the DURAMAX tuning. I can't believe CUMMINS would put out tuning with problems like this in it, glad to see EFILIVE has helped you guys get driveable big HP trucks now too.
 
SixOhh said:
phale is right.. im in my first week with the v2 and the first thing i did was pull my stock tune and look at the timing and duration maps and WOW. it makes you wonder.. who the hell made the factory tune and why is it so primitive!

i am so impressed with the things people have found in tuning it makes my mind wander. the fact that we can really SEE EVERYTHING now is all there was to it!

i will be monitoring 2 different tunes and logging in the next week to see what affects throttle hang. i dont claim to be a genius but all i can do is log and learn right?!
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Any update on your findings?
 
So back to it, I finally bought my EFILive but haven't had time to install on the computer yet. I am not 100% new to tuning, but I'm new to diesel tuning, and new to EFILive. I've used HPTuners enough to grasp the basics of gasser tuning. FWIW. :(

Can we reduce the rail hang by severely scaling back the pulse width when coming off the throttle?

Also so far are you guys finding one OS to be superior to another, for any reason?
 
Be ready to download a different OS for your truck from the tune library right from the get-go. That Bully Dog don't play nice.
 
Oh I figured that.
And out of curiosity, can I read the BD tunes so that I can at least see what they were doing? I'm sure they were accessing tables that we can't yet see, but I'd love to see how badly it's written to cause the rattle rattle thunder clatter that I hear. Haha. I know if I use its timing as the likely upper limit to my settings, I should be just fine, IMHO, as I build from scratch. Looks like this weekend or next will be spent strapped to Bluecat's dyno.
 
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AdamRRT said:
I see but one issue with the pressure theory:
Why are the injectors firing?
If it's pressure, it shouldn't matter if there's no pulse to fire the injectors.
I'm no master tuner but I have enough experience to grasp the basics. And knowing how an injector works. Pressure doesn't explain injectors firing when they're not needing to.

Maybe you can taper them off faster? When my foot comes off my pedal, my injectors shouldn't be firing. At all.
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only in an 05 up 6 liter at low speeds. What is going to keep your engine spinning in an auto with the tc unlocked? It should always idle!
 
RPM hang related to RP is tunable in tables D0782, D0781, D0771, D0774, D0777. Tuning to eliminate RP related rpm hang in tables other than these is a futile effort at best.

With EFI-Live there is no myth in tuning. Data log a lot, change a little.
 
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6btdakota said:
only in an 05 up 6 liter at low speeds. What is going to keep your engine spinning in an auto with the tc unlocked? It should always idle!
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True. I guess I over-simplified. So as said in the rest of the post, seriously scaling back the injectors is what I mean, because yes of course there will be an injection event. Just thinking it could be appropriately scaled down so that the high pressure + low duration = idle amount of fuel (basically).
 
AdamRRT said:
True. I guess I over-simplified. So as said in the rest of the post, seriously scaling back the injectors is what I mean, because yes of course there will be an injection event. Just thinking it could be appropriately scaled down so that the high pressure + low duration = idle amount of fuel (basically).
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Wrong. There are safety factors built into the software that are not tunable.
 
Here is a visual on the fix!

These screen shots are taken at relatively the same angle. MM3 along the bottom left, RPM along the bottom right and MPA up the right side. This is the best way I've found to combat the issue. Have fun guys! ;)

Stock RP table
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No RPM Hang RP table
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Fueling error (commanded vs. actual) increases significantly with use of multiple injection events. That's potentially be one of the factors contributing also. Easymon's mention of it getting better with no pilot would agree with that also. Are you commanding an on-time...or a fueling value?

If you're coming off a high fueling and high rail pressure condition, and down to a lower rail and commanded fueling. I could see where there'd be some hang. The pump may have a hard time cutting pressure quickly enough. And commanding low idle-like fueling, split across a pilot and main event, it's likely overfueling. The injectors probably struggle as it is to have real consistent shot-to-shot fueling at the low idle fueling values...even at the much lower rail pressures it's normally running at idle. It likely can't inject that small amount of fuel with such high rail pressure...and splitting across two events will make the fueling error worse.
 
Stock tune. Let's fix it on a stock tune however we have to - removing pre & post, etc. Then we can work on a modded tune. You feel you are ok fixing that? I've had no luck removing it.
 
Have any of you tried fixing RP hang the way I showed in my previous post?
 
In my testing, it's not the rail pressure causing the hang. I have not had the hang for a long time in my tuning, so was curious why so many were. I made tunes with just one table modded on my no hang tunes, then tested many versions and found some interesting stuff. These Cummins surprise me again and again how different they react to adjustments opposite of the duramax.
 
And so what did you find, Rob? Lol the important part of the post is missing. You've been using EFI live on Dodge Cummins from the beginning and before, right? I'd love to hear your input. Thanks.
 
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The Cummins does tune way different than a duramax. The difference is American vs Asian...I find the Cummins more my type LOL
Rob, if throttle hang is not RP related is it possible that something else in your tuning is causing throttle hang? I have not seen any throttle hang since tuning the RP...
 
LReiff said:
Rob, if throttle hang is not RP related is it possible that something else in your tuning is causing throttle hang? I have not seen any throttle hang since tuning the RP...
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I don't see throttle hang in my tuning. I tried to duplicate what others have been saying to see where the issue is.

If the throttle hang is present in a stock tune, then best to install one of the newer OS's that don't have the issue in stock form. This way you are starting out with a good foundation in which to tune.
 
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