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Discussion Starter #1
Hello,

I am new here...I just got a 2011 GMC Duramax Z71 last Friday.

I was told that I shouldn't leave my truck idling for prolonged periods of time. However, some of my friends with the same truck said that if I activate the high idle (not elevated idle) switch then it would be OK because the DPF stuff can operate...

I just wanted to make sure this is right.

Thanks for the help in advance. :drink
 

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No, High Idle is not going to change that. The DPF cleans its self out at somewhere over 1000 Degrees. Your truck EGTs are not going to be 1000 idling. High Idle or not.
 

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It does help burn the extra fuel in the LMM's, other than that high idle is not nessicary
 

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It does help burn the extra fuel in the LMM's, other than that high idle is not nessicary
LMM did not have the high idle switch option(used via the cruise buttons at idle at any engine temp). This is a 2011 option.

The LML will not regen at idle, priod. The benefit of the high idle switch(not cold elevated idle) is to keep the engine from cooling down too much during extended idle periods. A cool engine is more prone to unburned diesel getting into crankcase.
 

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Discussion Starter #5
Thanks for the replies. So, I guess letting it idle for a long time is out of the question?

Also, how long is too long to let it idle?
 

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Thanks for the replies. So, I guess letting it idle for a long time is out of the question?

Also, how long is too long to let it idle?
I have idled mine for 45 min at reg idle speed (650 rpm) many times with no adverse affects. If it is real cold below freezing use the high idle switch to prevent coolant temp from dropping too much and idle at will. Hotter in cylinder temps equalls less unburned fuel ,hence less soot to DPF|
 

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Well when you idle the truck for a long time yes your DPF can get a little touchy. My bud's LMM would get clogged and limp when he would idle it forever in Colorado. He got a high idle to help with the DPF getting clogged.
 

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Discussion Starter #8
I have idled mine for 45 min at reg idle speed (650 rpm) many times with no adverse affects. If it is real cold below freezing use the high idle switch to prevent coolant temp from dropping too much and idle at will. Hotter in cylinder temps equalls less unburned fuel ,hence less soot to DPF|
Well, that's good to know. I was worried about letting it idle for 5 minutes while in a convenience store after I talked to the dealer about the damage done by "excessive" idling not being covered under warranty.
 

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Well, that's good to know. I was worried about letting it idle for 5 minutes while in a convenience store after I talked to the dealer about the damage done by "excessive" idling not being covered under warranty.
When it comes to diesel truck emissions, most of them are clueless. They can NOT void your warranty due to prolonged or excessive idleing. None of their business how you use the truck. If you get the truck out on the hiway, or tow /haul once in a while you should be fine. You will hear lots of stuff from non educated people about how your new diesel can't be idled, DEF is gonna fail, DPF is gonna plug up, don't drive on Sunday after noon, use the tow/haul ONLY when towing. Take it all with a grain of salt and find a DMAX tech that is in the KNOW. My favorite to date is when people say you can't find DEF anywhere and have to drive accross the country to find it somewhere :cookoo[1]:. WAL-Mart sells it, Canadian Tire sells it, Auto Parts Plus sells it , Lordco sells it, truck stops sell it.:drink
 

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haha sorry to change the topic, but Denali3500 i love your quote in your signature! its too bad us denali owners are gay!
 

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theres an easy solution, delete the dpf etc.

just saying....
 

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Discussion Starter #14
theres an easy solution, delete the dpf etc.

just saying....
Well, I am pretty sure that will completely void the warranty...if I could get away with it, I probably would do it, though. I have heard it increases gas mileage quite a bit.
 

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theres an easy solution, delete the dpf etc.

just saying....
$55 000 dollar truck with no warranty might be a tough sell to my wife.:rof
 

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EFILIVE,y u no DSP5 LML??
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$55 000 dollar truck with no warranty might be a tough sell to my wife.:rof
That would be a tough sell for me, much less my wife!!! I didn't pay this much money to throw away my warranty:cookoo[1]:, Now in a couple of years I will def do some mods!!:drink
 

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Just thought I'd add my two cents I've been driving tractor trailers for 20 years and the only reason I knew of to keep the truck ideling at high idle was to keep the temps up so you could keep the truck warm or cold also truck drivers idle their trucks 24/7 to keep them warm or cold. I got a high idle switch option on my truck so I could idle it when I'm out of it and not get into a freezing cold truck when it's 20 friggin degrees outside. MAN I HATE THE COLD
 

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Boy am I glad I read this - Denalli called it right and helped me with my problem- I have been known - on occasion to drive after noon on Sunday..... Drive the truck and enjoy.
 

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haha sorry to change the topic, but Denali3500 i love your quote in your signature! its too bad us denali owners are gay!
I hope my wife never finds out :rofl :drink
 

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Discussion Starter #20
So, the consensus is that it is OK to leave it idling for a little while (~45 minutes), but not for a long time (like overnight)?

Also, is there any way to configure my remote start to be able to leave the truck running while I go into a store and be able to take my keys with me and lock the doors? For example, when I pull up to a convenience store, can I do anything to let the truck idle and remove the keys or do I have to turn it off and remote start it again?
 
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