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I'm scaring the crap out of myself. Just bought my 2018 PM 136 and I can't make a smooth start. No matter how gently I depress the accelerator it's always a sudden start which several times has sent me into the oncoming traffic lane or almost sent me into the rear end of the vehicle in front of me. Is this normal for it to start that quickly? This is my first experience with a front wheel drive vehicle. Thought I would ask here first before taking it back to the dealer.
 

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keep driving it slowly. it takes awhile for the transmission to "learn" how you drive.

mine accelerated very quick at first, now it behaves nicely.

disconnecting the battery will start the learning process all over.
 

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my guess is your not used to not having anything to the right of your foot, it kinda has to stand on its heel, move your foot to a different position, experiment. I think the design of the pedal is your problem, youll get used to it. (hope your not using the tip of your shoe....or hitting just the bottom of pedal)
 

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I have the same issue, van is way too "jumpy" accelerating from a stop or from slow speeds. I thought it was just programmed that way for american consumers who need a "compensator" to feel better about themselves.

I didnt know that the transmission learns your driving behavior, mine feels the same as it did the last time I disconnected the battery.
 

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We haven’t had many people have this problem. Perhaps it’s psychological? If you’re not used to driving a big vehicle at first you unconsciously think you need to "step on it" to get it moving. Most new owners are surprised buy the power of the van.

Also. It’s "drive by wire" accelerator perhaps you’re used to a cable or even an accelerator rod?
 

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Mine is the same way. I just take my time and press lightly. I'm not the fastest off the line, but I'm experiencing the sudden lunge forward. Is this a joke about the transmission learning your driving. Seems a bit much for a basic cargo van.
 

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No joke, the computer learns your driving habits and programs the transmission accordingly. This is true with most modern vehicles.
 

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Mine was also exceptionally lurchy off the line. Even at 8k pounds! It does seem to have gotten a little better, or I got used to it. It still lurches. Want proof? try starting off on wet grass in this van without lighting up the front tires! Hahaa. Not a chance.
 

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It's touchy IMO. I think the tip in point is too aggressive. Took a while for me to get used to it.

Sent from my Nexus 6 using Tapatalk
 

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Yeah, ours was jumpy at first, too. But eventually we learned along with the tranny and it's not so bad anymore. These things also have a pretty low first-gear ratio (think truck granny gear) which contributes to the issue, too. Easy does it.


That said, starts on slick ground can be problematic. How do ya'll in the snow belt manage this issue?
 

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This seems odd. My PM isn't at all jumpy or touchy (I've only had it four months), nor did I notice an issue with a different van that I test drove previously. The brakes took some getting used to, but accelerating from a stop is smooth.


I'd ask the dealer if there's some sort of adjustment that needs to be made.
 

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Most new owners are surprised buy the power of the van.

Also. It’s "drive by wire" accelerator perhaps you’re used to a cable or even an accelerator rod?
The jumpiness/twitchyness is not a symptom/symbol of excessive power, it has to do with the software which is providing the connection between gas pedal position and engine throttle. It has been intentionally programmed to react quickly to a small movement of the accelerator pedal. I (and it sounds like others from this thread) would prefer to the power curve to be more linear, instead of a steep curve in the beginning followed by a shallower curve. I am certain the van was intentionally programmed this way to "surprise the driver by the "power of the van", just as you state. I wish consumer preferences were different. I wish there were a way to reprogram it to be less twitchy when starting from a stop, it seems this would improve fuel economy and be safer and be easier to drive. Other vehicles have settable "drive modes", such as a "test drive mode" which is a unnecessarily dangerous and inefficient mode designed to surprise prospective buyers by the power of the vehicle during a test drive.
 

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...it seems this would improve fuel economy...
There is no engineering basis for this assumption. Technically engines are most efficient at maximum load. The best fuel economy should be obtained by opening the throttle generously while shifting up as soon as possible without lugging the engine in the next gear. The objective should be to get to highest gear with the fewest total engine rotations. This is easier with a stick shift, but you can lift off the throttle to induce an upshift and re-apply as much throttle as possible without forcing a downshift. This is where an economy mode would actually make a difference (hold current gear with higher throttle position).

The problem is that people look at the instant economy gauge and jump to the conclusion that lowering your rate of acceleration increases overall fuel economy. What they overlook is all the extra distance they could have travelled at a steady 35 or 45 mph where in fuel economy can easily be in the 30s. Instant mpg sucks when you are accelerating no matter what your acceleration rate. Getting 12 mpg and taking 600 yards to get to cruise speed is no better than getting 8 mpg and taking 200 yards. Also, if you miss the next light by a few seconds because you didn't accelerate fast enough, you are definitely wasting gas.
 

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Just took delivery last month of a brand new 2018 136 low roof. I will say that mine was very touchy until maybe last week. I would have to say that the transmission "learning" idea seems very plausible. I don't think I've changed my technique so much as to have stopped the van from the former lurch. In fact, I can't hardly make it lurch even with some effort. I have to say that I sort of liked that initial setting because I'm chronically light footed with vehicles.
 

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Hey guys this isn’t some wimpy diesel it’s a real performance van! It’s a real gas ;)
Isn’t inserting a comment like this called a red herring? To jump to the “bait” I’d suggest the behavior may be why the gasser gets 17 mpg and my manual diesel gets 27!
 

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There is no engineering basis for this assumption. Technically engines are most efficient at maximum load. The best fuel economy should be obtained by opening the throttle generously while shifting up as soon as possible without lugging the engine in the next gear. The objective should be to get to highest gear with the fewest total engine rotations. This is easier with a stick shift, but you can lift off the throttle to induce an upshift and re-apply as much throttle as possible without forcing a downshift. This is where an economy mode would actually make a difference (hold current gear with higher throttle position).

The problem is that people look at the instant economy gauge and jump to the conclusion that lowering your rate of acceleration increases overall fuel economy. What they overlook is all the extra distance they could have travelled at a steady 35 or 45 mph where in fuel economy can easily be in the 30s. Instant mpg sucks when you are accelerating no matter what your acceleration rate. Getting 12 mpg and taking 600 yards to get to cruise speed is no better than getting 8 mpg and taking 200 yards. Also, if you miss the next light by a few seconds because you didn't accelerate fast enough, you are definitely wasting gas.
Thanks for pointing this out, I read about this and you are correct, the engine is not at its most efficient at low rpms, its also not very efficient at high rpms, it is sort of a U shaped curve where efficiency is worst at the extreme throttle ranges. To me it feels like the promaster is accelerating from a stop at the inefficient high end of the range but we would need more data about the engine to know that for sure. I understand that staying in low gears longer will lead to inefficiency. Perhaps using the "resume" function on cruise control would result in the most efficient acceleration speed? I dont pay any attention to the instant mpg number on the dash, its useless information to me.
 

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The jumpiness/twitchyness is not a symptom/symbol of excessive power, it has to do with the software which is providing the connection between gas pedal position and engine throttle. It has been intentionally programmed to react quickly to a small movement of the accelerator pedal. I (and it sounds like others from this thread) would prefer to the power curve to be more linear, instead of a steep curve in the beginning followed by a shallower curve. I am certain the van was intentionally programmed this way to "surprise the driver by the "power of the van", just as you state. I wish consumer preferences were different. I wish there were a way to reprogram it to be less twitchy when starting from a stop, it seems this would improve fuel economy and be safer and be easier to drive. Other vehicles have settable "drive modes", such as a "test drive mode" which is a unnecessarily dangerous and inefficient mode designed to surprise prospective buyers by the power of the vehicle during a test drive.
I agree with this 100 percent. I even noted it when I was test driving. Feels quick in the parking lot, but is a dog on the on ramp.
 
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