DFCO doesn't activate often

[TGI-Germany]

Hello Guys,

 

i have registered new to this board. I've read much in the past but haven't been active here.

 

I bought this year a ´17 Black Silverado HC with the awesome 6.2 V8 and the 8 spd tranny. Georgeos Truck - best vehicle i've ever driven. I put some Pics here later.

 

I got a question - probably someone can give me advise or tell me its just normal.

 

My DFCO (deceleration fuel cut off) kicks in very incosistently. Once the engine is warmed up i will activate for the first decelerations when i let off the throttle. But after a few minutes most of the time it won't kick in again. Sometime i think it is about ambient temperature - when it was colder it was also less often. When at highway speed it literally never activates. I have no clue why. 

I have no check engine lights or other issues. 

 

Regards and thank you in advance for everything which help me to determine the problem

[2kwik4u]

How are you detecting DFCO?

 

The only way I can tell in my '15 5.3 is by watching the instant fuel economy if it spikes to 99, then I know the ECM has turned off the injectors. Otherwise it is completely unnoticable to me.

[JimCost2014]

Welcome to the site!

 

Agree with prior post, if you can feel the fuel shutting off, think you have a problem with the truck.

 

Should be a seamless transition when it is working correctly.

[TGI-Germany]

3 hours ago, 2kwik4u said:

How are you detecting DFCO?

 

The only way I can tell in my '15 5.3 is by watching the instant fuel economy if it spikes to 99, then I know the ECM has turned off the injectors. Otherwise it is completely unnoticable to me.

I detect it by the instant MPG, and there is more deccelleration if activated. 

 

If it activates it is nearly seamless - but it doesnt activate often.

[2kwik4u]

14 hours ago, TGI-Germany said:

I detect it by the instant MPG, and there is more deccelleration if activated. 

 

If it activates it is nearly seamless - but it doesnt activate often.

Interesting.

 

Wonder if one of the guys that has tuning software can compare the DFCO tables between the 6.2 and the 5.3 to see if there are any noticeable differences there. If nothing else might give some insight into how it's supposed to work so you can check against real world usage to tell if there is a problem or not.

 

I don't have HPTuners anymore (although I've been considering getting a license again) or I would check myself.

[TGI-Germany]

on a "good" day when it activates often city MPG is also way better than on the "bad" days when it doesn't activate often.

 

Since we are in Germany located there is no warranty or dealer i can ask for help.

I'm thinking about a programmer/scanner/tuner to read out all values to recognize everything "strange"

any recommendations for a tool? If i am right informed the 8spd tranny is on lock down so it can't be programmed anyways.