Throttle hang?

[AdamRRT]

Any auto trans guys having any luck on removing the throttle hang that's so bad in these trucks? I know I seem to hear of it mostly in 2006 trucks but always autos. I love a good custom tuning option as I'm originally a GM guy and miss HPtuners with this Dodge. So I'll buy EFIlive soon.

But so I know what to expect regarding my expectations, any luck removing throttle hang?
Trans tuning released yet?

Thanks guys. Looks like I'll buy in a week or 2.

[phale]

It is all in the rail pressure. Some trucks respond differently than others, but for the most part it can be greatly minimized. As an example though, I sent out a file yesterday that I have ran on several trucks without throttle hang issues and the customer says his still hung on shifts (manual tranny) so everything is different. Once you get the software and look at the factory settings you will see why it hangs.

[AdamRRT]

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.

[SixOhh]

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?!

[AdamRRT]

That still doesn't explain why the injector is firing. It shouldn't be firing. Duration & pressure don't put fuel into a cyl that isn't getting an injection pulse signal. Surely we can agree on such a basic concept of tuning and mechanics.

[phale]

The injector is still firing, just because you let out on the throttle does not mean that the injector stops firing instantly, the pulse width just drops significantly but there is still fuel entering the cylinder for a few milliseconds, and the high rail pressure forces more quantity of fuel through the injector with the same duration than when it bleeds off the pressure to a lower level.

[AdamRRT]

True. So are the injectors just not as scalable as we need? I mean yes sone firing but just at a lower pulse width than idle we could manage that pressure couldn't we? I understand if they're just horribly unresponsive or the scaling just isn't there. Just seems we should be able to open the fuel pressure return and scale back the injectors and there would be no issue.

So is it that they're just not responsive or the scaling is just not fine enough?

I'm still trying to get a tuning genius friend if mine to convert me to a GM COMPUTER. LOL. He did it with a Polaris 4wheeler, so I'm sure he could do it with this. But can't get him interested. :(

[easymon]

just a beginer here but seems that with no post pilot dont seem to hang like it dos with it on . Been playing with zacks tunes at starlite.

[phale]

True. So are the injectors just not as scalable as we need? I mean yes sone firing but just at a lower pulse width than idle we could manage that pressure couldn't we? I understand if they're just horribly unresponsive or the scaling just isn't there. Just seems we should be able to open the fuel pressure return and scale back the injectors and there would be no issue.

So is it that they're just not responsive or the scaling is just not fine enough?

I'm still trying to get a tuning genius friend if mine to convert me to a GM COMPUTER. LOL. He did it with a Polaris 4wheeler, so I'm sure he could do it with this. But can't get him interested. :(

This is where we get into the land of the unknown. Within a few miliseconds of letting off the throttle the commanded duration does drop to 0, but there may be something in the software that tries to bring the revs down gradually rather than as abruptly. Also you have to consider the PID tables and how the truck is responding to changes in the rail pressure. I could type 2 pages about what I think is happening but it is only my theory. I can tell you that by tapering off the rail pressure as you approach your max rpm and playing with the PID tables you can really minimize the throttle hang in most cases.

[StarLite Diesel]

I believe we have narrowed it down to an OS issue.... in fact an issue that I 'think' the factory learned about and fixed. During beta testing I had a truck that when he bought it, had the throttle hang - and his truck was completely stock.

He went to the dealer several times and finally they updated his ECM with a new OS for his truck. Poof. No more throttle hang. I have used this OS on any customer trucks that compalined about having throttle hang previously with great success. No complaints from any of my customers about throttle hang.

We have now successfully stretched out RPMs and fueling limiters to the point where even on modded trucks if it was simply a rail pressure condition we'd have hangs happening all over the place.

I realize this doesn't complete answer the 'why' for the throttle hang, but I think the bigger point is that we have a clean way around it....

[icemanjc1]

I believe we have narrowed it down to an OS issue.... in fact an issue that I 'think' the factory learned about and fixed. During beta testing I had a truck that when he bought it, had the throttle hang - and his truck was completely stock.

He went to the dealer several times and finally they updated his ECM with a new OS for his truck. Poof. No more throttle hang. I have used this OS on any customer trucks that compalined about having throttle hang previously with great success. No complaints from any of my customers about throttle hang.

We have now successfully stretched out RPMs and fueling limiters to the point where even on modded trucks if it was simply a rail pressure condition we'd have hangs happening all over the place.

I realize this doesn't complete answer the 'why' for the throttle hang, but I think the bigger point is that we have a clean way around it....

I'll have to agree on this. My original OS along with another from an 06 hangs up pretty badly (I call it rail hang). I recently swapped my tune to an 07 OS and it, for the most part, cured it.

[AdamRRT]

Oh sweet. So when I get EFIlive are there any 07 OS's in the repositories? I'd love to get it fixed.

[EFI Support]

All stock tunes are available for download in the tune library to ensure customers who's trucks were not returned to stock by their previous programmers can tune with EFILive.

Cheers
Cindy

[THEFERMANATOR]

I was recently working on an 03, and when you revved it WOT it would take almost 2 seconds before it would return to idle. Is this the hang that you guys are refferring to? this was a stock truck, and I know I sure wasn't impressed with it compared to my DURAMAX as far as the tuning smoothness went espescially the delay to return to idle it had in it when you would floor it.

[chizwizdiz]

I was recently working on an 03, and when you revved it WOT it would take almost 2 seconds before it would return to idle. Is this the hang that you guys are refferring to? this was a stock truck, and I know I sure wasn't impressed with it compared to my DURAMAX as far as the tuning smoothness went espescially the delay to return to idle it had in it when you would floor it.


This, and on hard acceleration while driving. If you let off of the throttle, it will continue to pull for a second or two.

[easymon]

Hey guys can some 1 tell me what to do to change os from tune depot after it down loads .Do i flash truck then change vin not sure and then how to change vin if need to thanks shannon

[icemanjc1]

Hey guys can some 1 tell me what to do to change os from tune depot after it down loads .Do i flash truck then change vin not sure and then how to change vin if need to thanks shannon

Download it, load it to your truck with whatever settings you see fit. When it's done, with the V2 still connected, open 7.5 scan tool, click on the green button (upper left hand corner of the screen) to connect to the ECM, then click on the drop down menu from the menu bar at the top called bidirectional, click change VIN... Enter your new VIN. Presto.

[easymon]

Thanks for info. shannon

[IdahoRob]

Many months ago Bobo and I tested the OS theory. We had two trucks. one with the hang and one without in stock form. Basically the same configuation also. We installed the exact same tune in each truck and nothing changed between the two. Wasn't tuning, but certain OS's. Can tuning cause throttle hang? yes. Can tuning fix a OS that has the hang issue? not that I've seen (can be improved though)

[Red Sleeper]

Can someone elaborate on OS for those who don't understand it, including myself? Don't know all the abbreviations for everything.. I have throttle hang on my stock 05 pretty bad. I went to the dealer to ask about an updated flash and they couldn't tell me much about what it offered/fixed and improved on and it would cost $105 being it's not a recall.

One thing I'm hoping it has is the feature where the key can be off and the radio still plays until you open the door for gauge readout reasons... Just wondering if someone could explain it.

[ComnRailPwr]

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

Jake

[THEFERMANATOR]

This, and on hard acceleration while driving. If you let off of the throttle, it will continue to pull for a second or two.


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.

[Red Sleeper]

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?!


Any update on your findings?

[AdamRRT]

And just think, they are still opening up more and more tables.

[AdamRRT]

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?

[icemanjc1]

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.

[AdamRRT]

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.

[6btdakota]

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.


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!

[LReiff]

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.

[AdamRRT]

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!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).

[LReiff]

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).

Wrong. There are safety factors built into the software that are not tunable.

[LReiff]

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
http://www.competitiondiesel.com/forums/attachment.php?attachmentid=31504&d=1315591651




No RPM Hang RP table
http://www.competitiondiesel.com/forums/attachment.php?attachmentid=31506&stc=1&d=1315591932

[AdamRRT]

Nice. So stick to a stock 06 base tune? 07 has no advantage?

[LanjPerf]

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.

[AdamRRT]

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.

[LReiff]

Have any of you tried fixing RP hang the way I showed in my previous post?

[IdahoRob]

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.

[AdamRRT]

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.

[LReiff]

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...

[IdahoRob]

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...

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.

[LReiff]

On all the stock tunes I've played with throttle hang only happens when the engine is reved past 3200 and the throttle pedal is fully released. Most only realize throttle hang is an issue at the end of a run when sled pulling. The engine is seldom reved past 3k on the street because mildly modded stock tunes don't make power up there.

[Blazin Dmax]

so does any one know if the 35325551 OS for 06 federal manual trucks has rail hang in stock form?