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Discussion Starter · #1 ·
Noticed something while driving around - usually occurs at very low speed (i.e. a stop and go - more of a rolling stop at a stop sign :eek:).

I will push the throttle down - and no/limited response - and then all of a sudden it kicks in and I am accelerating faster than I planned. I know the immediate response will be Turbo Lag, but that is not what this is (There is no wind up in the engine - it more no response at all). It reminds me of a previous car I had that had "Throttle by Wire" (like fly by wire) - you could literally push the pedal to the floor and release - and if you did it fast enough the engine would not respond.

So - anyone know if this Truck is a traditional cable to throttle body - or a wire to a computer chip?

My other thought is the result of the Transmission "learning" my driving style and not allowing everything to respond. I am going to test it out later today by turning Traction Control off, which should remove some of the computer inputs out of the equation.

Not really a big deal - more of a question. It is entirely possible I have to adjust the way I drive.
 

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................huh, I still think it is turbo lag, experiencing the same thing.

I own another car with throttle by wire (it's all going that way) and twin turbos. No lag here, she will jump and one actually has to be very easy and careful on the throttle in tight places.
 

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Throttle by wire, shift by wire, but not fly by wire. I still have mechanical devices connected to my steering wheel. ;-)
 

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All of the new diesels do this. Its a initial torque limiter done in the fueling and timing. It ramps up the power electronically to save the driveline and make the car operate smoothly. Then, because its limiting the "throttle" timing when you take off, the turbo becomes even more laggy because its not getting the airflow to spool it.

A proper tune will get rid of 99% of this. Moves torque limiters as well as adds more fuel down low to fill the lower powerband.
 

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You could also try this to make the truck more responsive. Not sure if it works the same way in the diesel, but worth a try.


From another forum, Originally Posted by brandonjansen.
Throttle response calibration. If the first half of your pedal travel feels useless something seems off. I feel like I rarely go over half travel for everyday driving.... Turn your key to the run position, wait for all the lights and chimes to go off. Slowly depress the gas pedal all the way to the floor, and then slowly release it all the way up. Turn the key back off. Then start the truck. Most people do notice a significant increase in throttle response after doing that.

You can also try not going all the way to the floor but maybe 3/4 to see if it makes it even more responsive.
 

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You do it. Let me know. If I try it will probably screw things up.
 

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All of the new diesels do this. Its a initial torque limiter done in the fueling and timing. It ramps up the power electronically to save the driveline and make the car operate smoothly. Then, because its limiting the "throttle" timing when you take off, the turbo becomes even more laggy because its not getting the airflow to spool it.

A proper tune will get rid of 99% of this. Moves torque limiters as well as adds more fuel down low to fill the lower powerband.
If you don't feel the "full" torque when going full pedal from a standstill, that is the fuel limitation to prevent excessive black smoke from being produced due to a lack of airflow in that maneuver. This is necessary so that you don't blow huge plumes of soot into the DPF and fill it instantly.
The 8HP70 driveline doesn't require any torque limitation, since it's carrying capacity is more than the engine can give anyways under ideal conditions.

The comment about "recalibrating" the pedal travel at key-on doesn't work on the Ecodiesel.
 

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Its not a torque limiter for the transmission because it cant hold it, its to help longevity of it, as well as the driveline mounts. No jarring, only smooth rolls into power. You are correct, it also rolls into it to help with soot. But the new diesels all work off AFR's, TPS, and many other sensors. I more than guarantee there is a ramping of throttle for drivability and emissions. Even new gas cars have that. Its tuned into the ECU via TQ limiting.
 

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Discussion Starter · #10 · (Edited)
................huh, I still think it is turbo lag, experiencing the same thing.

I own another car with throttle by wire (it's all going that way) and twin turbos. No lag here, she will jump and one actually has to be very easy and careful on the throttle in tight places.
It is not lag. I experimented last night on the way home. While driving I could push the pedal all the way to the floor, and release (all in one motion) - with zero response on the throttle. Did this 2 or 3 times.

The fuel consumption gauge also does not indicate an increased demand for fuel - which it should when the throttle is pressed.
 

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Discussion Starter · #11 ·
You could also try this to make the truck more responsive. Not sure if it works the same way in the diesel, but worth a try.


From another forum, Originally Posted by brandonjansen.
Throttle response calibration. If the first half of your pedal travel feels useless something seems off. I feel like I rarely go over half travel for everyday driving.... Turn your key to the run position, wait for all the lights and chimes to go off. Slowly depress the gas pedal all the way to the floor, and then slowly release it all the way up. Turn the key back off. Then start the truck. Most people do notice a significant increase in throttle response after doing that.

You can also try not going all the way to the floor but maybe 3/4 to see if it makes it even more responsive.
I will try that tonight. I have noticed when accelerating that the best ( or at least what feels like the best) is 3/4.
 

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Any difference? Same issue here, and same "eh, it's just lag". Noticed yesterday and today, after coming off the highway from my commute (76 miles each way), the lag was still there, but it is seriously reduced.
 

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All has to do with emissions my 12 cummins had same issue. I occasionally drive school buses with the big NAVSTAR engine and Allison transmission it does the samething. Those engines with out the limiting would jerk you back in the seat . It allis about that little filter behind the turbo charger....
 

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Discussion Starter · #14 ·
Any difference? Same issue here, and same "eh, it's just lag". Noticed yesterday and today, after coming off the highway from my commute (76 miles each way), the lag was still there, but it is seriously reduced.
Did not really notice anything. I am trying to narrow it down, as it does not always happen. I will be at a stop, and select the throttle and away we go. Then I will be at another stop, push the throttle - and - wait for - any minute now - and then bam it takes off like I was flooring it (and I probably was pushing the pedal harder).

The only common thing I have noticed, is it happens more when the vehicle is cold/just started. As I drive it seems to go away somewhat.
 

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All has to do with emissions my 12 cummins had same issue. I occasionally drive school buses with the big NAVSTAR engine and Allison transmission it does the samething. Those engines with out the limiting would jerk you back in the seat . It allis about that little filter behind the turbo charger....
Hmm, wonder if engine size has something to do with it (probably programming more than anything)? One of my trade in's was a '13 Golf TDi, which showed none of these issues in the shitload of miles I put on it.

Overall, can live with it, will just require a little right foot and gray matter recalibration.
 

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Laggy throttle response - Ecodiesel

All has to do with emissions my 12 cummins had same issue. I occasionally drive school buses with the big NAVSTAR engine and Allison transmission it does the samething. Those engines with out the limiting would jerk you back in the seat . It allis about that little filter behind the turbo charger....
This is entirely a throttle response programming issue. I notice this lag if you will when trying to merge into traffic from a stand still. Press the gas, nothing happens, and then all of a sudden your gone like a bat out of hell, but often much later than expected. You guys are not alone in your observations. The fix, get product called a "sprint booster":

Dodge Ram-1500 SprintBooster

...and here is a video on how it works...

 

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Did not really notice anything. I am trying to narrow it down, as it does not always happen. I will be at a stop, and select the throttle and away we go. Then I will be at another stop, push the throttle - and - wait for - any minute now - and then bam it takes off like I was flooring it (and I probably was pushing the pedal harder).

The only common thing I have noticed, is it happens more when the vehicle is cold/just started. As I drive it seems to go away somewhat.
Mine does the same thing, worse when it's cold, better when the engine warms up or the ambient temp is warmer.

I noticed that this started occurring after the last PCM flash that was applied about a month ago when I was having a cold weather DEF issue.
 
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Did not really notice anything. I am trying to narrow it down, as it does not always happen. I will be at a stop, and select the throttle and away we go. Then I will be at another stop, push the throttle - and - wait for - any minute now - and then bam it takes off like I was flooring it (and I probably was pushing the pedal harder).

The only common thing I have noticed, is it happens more when the vehicle is cold/just started. As I drive it seems to go away somewhat.
Ever heard of the designers protecting the engine and drive train from owners of diesel's that have no mechanical sympathy or common sense about properly warming up a diesel motor before getting on the throttle hard? It's an engineering design in the software/firmware, fueling programming that limits boost and fueling rates on cold engines, turbochargers, pollution control systems, etc, until everything is up to proper operating temperature and up to proper clearance tolerances. It's to prevent poorly trained operators from damaging very expensive equipment. It's self preservation, by the makers of the vehicle, so they can at least reach the end of their warranty with you the owner, before you destroy things on your own accord with poor operating practices.

Maybe go read your owners manual on proper warm up procedure for a cold diesel engine, as I am sure there is something in the Owners Manual about proper warm up procedure.


If you notice these observations, make note of it, and drive accordingly, so that you DON'T notice the symptoms you are complaining about... your truck is telling you, the operator, that you are being too aggressive before it is fully warmed up.
 

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Agree with Niner here... this is not a race car or sport truck. it's a high efficiency 1/2 ton hauler. why beat it up when it's cold?
 

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If I need to make sure I can accelerate when needed from a slow roll, I downshift to a gear that keeps the RPMs over 2,000. That seems to help.
 
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