Diesel Tuner's Blog

What causes the LML Dead Pedal?

Posted by Chris Ehmke on Aug 31, 2016 1:39:08 PM


Many customers have upgraded from their old pre-emissions Duramax to a new LML Duramax and found there are a few changes besides just the looks. 

The new LML made and astonishing 395 RWHP and 731 ft/lbs of torque on our dyno when tested stock. Which is impressive by itself but you will probably notice your old Duramax feels quicker. In fact we hear many stories of guys trying to merge into traffic or gun it to get in front of someone and the pedal does not seem to respond. This phenomena is often called the LML "Dead Pedal". The "Dead Pedal" is a delay the driver feels between pressing on the throttle pedal and the truck reacting as desired. 



But what causes the LML Dead Pedal? And more importantly, What is the fix for the LML Dead Pedal?

These are exactly the questions we hope to answer for you. Below you will see what we have put together on the topic. 

What causes the LML Dead Pedal?


Reason #1: Electronic Throttle Input

Many people refer to this as "Drive-by-Wire". It means there is no physical connection between the throttle pedal and a mechanical fuel injection system. Instead it is completely controlled by electronics.  This automation has the ability to change throttle response based on a host of inputs including  temperature, gear, 'run mode', and boost to name a few. 

Reason #2: Turbo Lag

Turbo lag is a term used to describe the time between hitting the throttle pedal and the truck reaching the desired torque output for set load point.  This delay is characterized by the time it take the turbocharger to reach the desired airflow rate or boost.  In todays modern engines, the turbocharger typically leads the fuel curve to the desired torque output in order to minimize particulate emissions.  The slower an engine accelerates, the easier it is to control particulate emissions. 

Reason #3:  Factory Calibration Strategy

Factory engineers have to consider a wide range of vehicle uses and driver skill levels when they calibrate throttle feel.  The best throttle feel for your 16 year old daughter backing up to a trailer is probably not the one you'd prefer for your daily commute.  We solve this one size fits all throttle calibration by adjusting the throttle feel based on how the truck is being used (towing, daily driving, racing etc.) 

What fixes the LML Dead Pedal?


The Fix: Custom LML Tuning

Custom LML tuning offers the driver the sensation of driving much lighter vehicle while improving mileage, throttle response, and of course peak power over the GM stock offering. Custom tuning is without question the best option for solving the dead pedal problem. 



Topics: Emissions, EGR Delete, 2013, 2014, 2016, DPF Intact, EGR ON, DPF ON, 2011, 2015, LML, How to program my LML, More Power for my LML?, what are some upgrades I can go to my LML?, 2012, DPF Delete, LML Tuning, Emissions Intact, LML Power, DEF fluid, NOX, 2017, regen