# Throttle delay, lag something, can't figure out why?



## obnxous (Jan 17, 2018)

Someone else was referencing this lag in the Gen1 gas thread. I have a 2015 CDI and the throttle lag is killin me. It almost seems like there may be a throttle position sensor issue but there are no codes. If I press on the pedal lightly the delay is 1-4 seconds. If I mash the pedal from the light, the lag is still the 1-4 seconds. In either case once the car hits 2200 rpms it shoots off like we are on a dragstrip. I have found that I can shorten that delay by 1 or 2 seconds by fluttering the pedal quickly but the lag is still there. How does everyone else deal with this kind of turbo lag, throttle response delay, whatever you want to call it when it goes from crawl to scream after leaving the light? Is there something else I can do to minimize the delay? Minimize the lag so its more responsive?

Currently I'm showing just over 50k miles, Averaging about 40 mpg running 55 - 80 for 90 miles per day. Which remind me, DEF is at 27% and I need to get some on the way home.

Thoughts? Has anyone else heard of or experienced this phenomena?


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## MRO1791 (Sep 2, 2016)

Actually it's not unusual for this car. That said there are tuners out there that make a big difference. The 2200 is about the peak torque for this engine, coincidentally.

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## mechguy78 (Jun 6, 2016)

The throttle is drive by wire. The lag you are seeing is the throttle body trying to catch up to the accelerator pedal via the pcm. I notice this on my 1LT when shifting gears.


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## HatchLifeRS (Oct 3, 2017)

With it being a diesel the only use for the throttle plate is to block off air in the event that the engine "runs away". When the engine is running the plate is fully open. Older diesels didn't even have a throttle plate, just an open inlet for air.

Just GM and their laggy ass throttle response.


mechguy78 said:


> The throttle is drive by wire. The lag you are seeing is the throttle body trying to catch up to the accelerator pedal via the pcm. I notice this on my 1LT when shifting gears.


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## MP81 (Jul 20, 2015)

The lag really isn't from it being DBW - it's a combination of torque management and turbo lag.


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## MRO1791 (Sep 2, 2016)

MP81 said:


> The lag really isn't from it being DBW - it's a combination of torque management and turbo lag.


Exactly, if a tune can dramatically change this parameter, that makes it clear beyond any doubt that it is part of the programming and engine control. And yes annoying to the driver. 

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## zigabric (Jul 9, 2018)

Hi, it seems the we have a similar issue. I have also noticed poor acceleration until the turbo kicks in. My throttle position sensor is reading that the plate is only 16% open when I drive (always). When I shut the engine off, it opens to 90% and closes. How does your throttle plate respond?


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## IndyDiesel (May 24, 2015)

How I deal with the turbo lag is just to be aware it’s there and not to put myself in a position that is dangerous. I have have a couple situations where it can be scary. Once the turbo kicks in the acceleration is very good. I had a similiar issue when had the cruze eco with manual transmission, first gear just gets you started and it wasn’t fast off the line either, I had more issues with it than the diesel. I am not an aggressive driver.


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## firehawk618 (Feb 24, 2013)

If I had to venture a guess I would say it's programmed this way to minimize soot on acceleration.

A gradual acceleration produces far less soot vs a sudden acceleration.


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## Jondaytona (Apr 26, 2018)

firehawk618 said:


> If I had to venture a guess I would say it's programmed this way to minimize soot on acceleration.
> 
> A gradual acceleration produces far less soot vs a sudden acceleration.


:iagree: ...plus the torque management to help keep the front-wheel drive diesel from roasting the tires off the line due to low rpm power diesels typically push.

If you read any of the aftermarket programmers' fine print, they explain how although throttle response will be dramatically improved, there will be a need for more frequent regen's due to excessive soot created during frequent heavy acceleration. Or something like that anyway.


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## Heatmover (9 mo ago)

obnxous said:


> Someone else was referencing this lag in the Gen1 gas thread. I have a 2015 CDI and the throttle lag is killin me. It almost seems like there may be a throttle position sensor issue but there are no codes. If I press on the pedal lightly the delay is 1-4 seconds. If I mash the pedal from the light, the lag is still the 1-4 seconds. In either case once the car hits 2200 rpms it shoots off like we are on a dragstrip. I have found that I can shorten that delay by 1 or 2 seconds by fluttering the pedal quickly but the lag is still there. How does everyone else deal with this kind of turbo lag, throttle response delay, whatever you want to call it when it goes from crawl to scream after leaving the light? Is there something else I can do to minimize the delay? Minimize the lag so its more responsive?
> 
> Currently I'm showing just over 50k miles, Averaging about 40 mpg running 55 - 80 for 90 miles per day. Which remind me, DEF is at 27% and I need to get some on the way home.
> 
> Thoughts? Has anyone else heard of or experienced this phenomena?


Turn off traction control , it makes the car run terribly, you have to push the pedal half way to the floor before it goes, turn off traction control and you will find that it is a whole different car, and your mileage will increase, the one I am driving jumped 10 miles per gallon


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