Throttle hang?

AdamRRT

AdamRRT

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Aug 3, 2009
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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.
 
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.
 
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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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?!
 
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.
 
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.
 
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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. :(
 
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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.
 
AdamRRT said:
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. :(
Click to expand...

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.
 
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....
 
StarLite Diesel said:
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....
Click to expand...

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


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

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.
 
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)
 
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.
 
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