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2021 cargo van - can throttle response be improved?

7K views 35 replies 17 participants last post by  icerabbit 
#1 ·
Just bought this van new. There is a delay when applying throttle at low RPM. For example, when making a turn into fast moving traffic, I press down on the gas pedal, expecting the van to accelerate immediately. Instead what happens is there is a delay of about a second before it accelerates. If I press down further on the pedal, it doesn't really make any difference except that a few seconds later the engine is now developing max power and I am screaming down the road as the load I am carrying slides to the back of the van.

I am guessing this is normal, probably designed this way to reduce emissions. What I am wondering, is if there is some way around this via chip tuning? I am reading about different types of add on modules that either work with the ECU or else modify the signal going from the pedal to the throttle. These seems to be designed with the aim of producing more power. I'm not interested in more power, just better throttle response. I don't care if I lose some fuel efficiency.

I'm actually surprised I don't see more on this forum about this. It's one of the few complaints I have about this van. I'm used to early 2000s vehicles so maybe everything is like this nowadays. Hopefully someone has some insight. Thanks.
 
#3 ·
Welcome to the forum.

There are a couple threads about tuning, that should show up via search.

I think a little turbo lag is to be expected. But the van is certainly no slouch and mine will throw the content around in the van when I press on the accelerator or brake pedal too fast. I have zero issues merging into fast traffic. The van does this faster the average vehicle and the minivans I had before my Metris. She's no E350 V6 turbo in sport mode, but she accelerates with far less effort than the average American minivan. If you had this complaint about Grand Caravan or Town and Country or Pacifica in eco mode ... for sure they're sluggish and fast merges take planning. With the Metris, I just step down a bit and she bites.

What were you driving before the Metris?
 
#8 ·
I also have the 2021 with the 9 speed transmission. I have this same issue, and I really don’t think it is a turbo issue, even though it sounds like it may be based on your description. It’s an issue of the new 9 speed transmission. As you slow down for a turn, the transmission doesn’t shift down through the last couple gears until you come to a complete stop. So, if you almost came to a stop, but then press the accelerator, there is a pause before the transmission shifts down to allow you the power to accelerate again.
if you use the paddles, and force it to downshift to 1st or 2nd just before you enter the turn, you’ll notice it immediately has the throttle response that you’re expecting.

too much computer control, and not enough good programming…
 
#10 ·
I have experienced this same issue with my 2021 Getaway. On my van you cannot change it into Eco mode, which according to some people, might help with the throttle response issue. I found that the only way I can avoid unwanted "surge" is to press the gas pedal with constant, but high pressure, if that makes any senseo_O. It seems to surge more with quick accelerating presses on the gas pedal with increasing force as you push down with your foot. I once tried a quick acceleration from a standstill, in the exact same situation as you described, by just mashing on the pedal. The turbo lag and perhaps tranny response resulted in very similar behavior from my van.
 
#12 ·
All this discussion makes me thankful I got a ‘20 instead of waiting another year. @patch.kit hit the nail right on the head. I am absolutely in love with the combination of the standard 2liter turbo and the 7-speed G-Tronic trans. The shifting computer always seems to make its up shifts and downshifts match my driving style of that moment, whether I’m in assertive mode or laid-back mode. I never use Eco mode - always Comfort mode.
 
#13 ·
I don't think anybody uses or misses Eco mode, because the computer defaults to Comfort every time you start the vehicle ... and there's only so many times you're going to press that button. I gave up on pushing the button. A light right foot is better for fuel economy than that eco button.
 
#14 ·
I've turned into a a regular Eco mode user on my '18 135 Cargo. Comfort mode makes the throttle response a bit too jumpy for my taste in stop/start driving. Eco mode seems more forgiving about accelerator pedal movement, especially off the line at low speed.

Back to the OP, my 7G-tronic van kind of jumps in C mode unless I am super careful to modulate the accelerator pedal very gently on start up.

I disagree that this is a "turbo lag" issue. The M274 starts hitting the turbo somewhere in the 1,400 RPM range, as I recall. There is virtually no turbo lag on Metris unless you drop the throttle to the floor from idle. In addition and surprisingly for a turbo, the M274 will let you get away with "lugging" it, i.e., low RPM in heavy load situations, without griping.
 
#15 ·
Thanks for the replies. One thing I have noticed, is that if I reduce the throttle position to zero, and then apply any amount of throttle, thats when the delay occurs. If I maintain 10% throttle opening and then apply more, it responds right away.
 
#16 ·
That does sound like it could implicate the turbo.
 
#17 ·
Yes, if you let off the gas entirely, hesitate, then want to motor fast, maybe she will need extra time as she is thinking you actually want to coast / decelerate.

I have an interstate on ramp near my house, up hill on ramp ... Coming from the traffic light stop or slow turn in, zero issue to get throttle response once the van is lined up ...

Same thing at highway speed. Zero issue to hit the next 10 or 20 mph from any speed, even loaded, to pass, fast merge, stick with traffic in the fast lane to get away from whatever cluster of vehicles that is frustrating you ...
 
#18 ·
We have a '21 with the 9G and also experience this. We live in a town with a lot of roundabouts, and get this 1 second delay every once in a while when applying the throttle from maybe 5-10mph or so. It's not the turbo. It's more like there is no acceleration during this brief time, and then once it's in gear it goes (and potentially REALLY goes because you keep depressing the accelerator wondering why you aren't speeding up yet). That's why I suspect the transmission is in the middle of shifting.

That said, now that we've had the van for three months, I don't notice it as much as when we first got it. I don't know if my driving style has adjusted to account for it, or if it has actually gotten better or broken in somehow.
 
#20 ·
There's a good chance your driving style has adapted too so as to avoid the lag. I find that driving a van is kinda Zen (sorry) in that you need to find the vehicle's rhythm and just go with it. The van is very determined despite being an inanimate object.
 
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#22 ·
Keep the load weight under1000lbs and strapped down in the center of your metris, you have the same drive train as the American made Sprinter it's very strong! I have carried several heavy loads and noticed the same electronic drag, it's it like towing a trailer, you need to adjust your driving Mitch
 
#25 ·
Folks, this has nothing whatsoever to do with the turbo nor the transmission. These vans (as do most new cars these days) have a "fly by wire" throttle, meaning there is no mechanical connection between the pedal and the engine throttle. My van has this same problem (2018 cargo). It doesn't happen every time, but when it does it's annoying. I'd MUCH prefer a mechanical connection. Listen to how he's described the problem: When he says, "there's a delay of about one second before it accelerates", he means IT DOES NOTHING AT ALL for that span of time. It feels like your vehicle has stalled, and then it's easy to react by pushing the pedal further, so when the throttle does engage it's like slamming it with your foot and going much faster than intended. I'm surprised we haven't heard of any accidents as a result of this already. I'd like to know myself whether this is something that will get worse later on, or is it just a minor annoyance that I need to get used to?
 
#26 ·
Drive by wire or not, throttle lag has EVERYTHING to do with the nature of a turbocharged engine - keep in mind we are talking low rpm driving’s situations here…if turbo has a last name it’s LAG

Turbo forces are secondary to engine RPM (turbo is recycling exhaust gases and reintroducing into the combustible cycle). It’s literally a force fed scroll or turbine - so there’s a pressure delay as it builds boost. it doesn’t really kick in until 2200- 2500rpm or once boost pressure is significant and sustained and can be fed back into the system. Choppy on/off throttle inputs at low rpm doesn’t work for the benefits of running a turbo. Sustained rpms 2200rpm+ (highway cruising) is where the efficiency and response of a turbo really benefit.

This has always been the nature of turbocharged ICE’s.
 
#27 ·
OK. I feel like this is going to go off the rails.

You can change the throttle curves without messing with the system with add on products. If you use Google things like pedal commander or box will take you down a rabbit hole....

I find my 19 to be zippy and I don't feel the need to mess with it. This from a person that has a rotary with a 3rd party computer and assortment of go fast vehicles. But knock yourself out.

I'd much rather tweak the brake response. It brakes good, but isn't linear like I want it.
 
#28 ·
There is a 1 sec delay ... surprised this has not caused accidents ... ?

What? Come on!

It really sounds like people never drove a van nor box van or even bigger vehicle before ... and are expecting Tesla / electric car level response.

How many times does one need a 1/2 sec critical accelaration curve response from a van, as if we were in some video game?

My 2l Metris with the same and even higher load is like a rocket compared to my 3.6l Dodge GC ... and I can go back in time across dozens of vehicles I drove that truly had no oomph ... all the way to my VW Golf 1 with 900 something cc ... that a Metris does just fine. Bit of turbo lag, maybe, but then you have to keep in mind these says that everything is focused on fuel economy.
 
#34 ·
There is a 1 sec delay ... surprised this has not caused accidents ... ?

What? Come on!

It really sounds like people never drove a van nor box van or even bigger vehicle before ... and are expecting Tesla / electric car level response.

How many times does one need a 1/2 sec critical accelaration curve response from a van, as if we were in some video game?

My 2l Metris with the same and even higher load is like a rocket compared to my 3.6l Dodge GC ... and I can go back in time across dozens of vehicles I drove that truly had no oomph ... all the way to my VW Golf 1 with 900 something cc ... that a Metris does just fine. Bit of turbo lag, maybe, but then you have to keep in mind these says that everything is focused on fuel economy.
I need to reply to this one since you're implying that I don't know how to drive a small cargo van. I've driven large trucks, as in a full size diesel truck across several states, several times. No, not a full time trucker, but enough to know what I'm doing. But regardless, if you're at a standstill, and you're ACCUSTOMED to your vehicle responding immediately when you push on the throttle, but then you get a delay (which feels exactly like a stall), your first inclination is to push more on the throttle, and with the excellent response from that engine being what it is, then yes, a sudden surge could, in fact, lead to an accident if one is, let's say, in close proximity to something, like in a parking lot, the car in front of you at a light, your own driveway, etc. I'm really confused as to why this is so difficult to understand.
 
#29 ·
Sorry guys, this isn't turbo lag. My van did it again yesterday, and it was more like 2-3 seconds. The delay is in the initial throttle response to the pedal. We're talking about moving the engine FROM AN IDLE to a speed FASTER THAN AN IDLE. The "lag" is a delay in the electronic response. That's it. If you're telling me that that is "turbo lag", then you have no idea what turbo lag is. And yes, it can cause an accident if a person overreacts to the lack of response by pushing the pedal harder, and then when it does respond you end up moving much faster than you want to. I'm a very experienced driver and have driven multiple vehicles with turbos. I know what turbo lag is, and this isn't it. In fact, the Metris vans have the least turbo lag of any turbo charged vehicle I've ever driven and it's quite impressive.
 
#30 ·
In fact, the Metris vans have the least turbo lag of any turbo charged vehicle I've ever driven and it's quite impressive.
This thread makes me sure I'll never replace my 2016 Metris with a newer one. I agree with KEM - the engine/turbo combination in my van is awesome. I'm constantly amazed at how well a little 4 cylinder 200HP engine moves the van. It's a hoot to drive in rural hilly roads precisely because there is virtually no lag, even at low RPMs, and the torque pulls it out of corners like a boss.

There's only one situation where I get the delay (and yes, it's very clearly due to software not turbo lag) that folks in this thread are reporting is all too common on the newer vans. There's a particular left turn at an intersection with traffic lights all directions. Crossing the intersection is uphill, so I've got the pedal down decently to accelerate, but I left to make the left turn. Most of the way through the turn, I push the pedal down to pull through the turn and accelerate up to the 55MPH speed limit. Nope. The problem is when I lift before entering the turn, the transmission upshifts to 3rd. When I try to accelerate out of the turn in 3rd, it takes the van at least two seconds to figure out what to do. I can have the pedal completely to the floor; no difference. It's because the pedal just goes to the computer, and the computer is confused. It isn't turbo lag because the computer hasn't responded to the pedal and given the engine any fuel.

The solution is for me to grab the left downshift paddle a moment after I lift the pedal before the turn causing a downshift back into 2nd. By the time I need to accelerate out of the turn, everything's settled, and the van pulls forward nicely - no turbo lag at all when the engine computer actually responds to the pedal input.

From everything I've read in this thread, it sure seems the newer vans suffer from a software or transmission problem. It's not turbo lag. KEM is right - this engine/turbo combination is amazingly awesome. Mercedes' software engineers (Bosch?) less so.
 
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