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Sorry for such a newbie question, but I just recentlly bought my first Diesel and I was wandering what are all the different opinions on leaving your truck running for long periods of time. A friend "a truck driver" told me it was better to leave your truck running than to shut it off. He said that Diesels use very little fuel while idleing. Just wandering what everyones thoughts are.

I have a GMC 04.5 LLY if that matters.
 

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well.... i've been told that letting them idle long periods washes the cylinders down. a lot of people have said to keep it under 15 minutes of idle time unless you can get the engine up over 1000 rpm for the idle time.
 

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exactly...if you don't have manual high idle mod, I would just shut it down. the engine does not make enough heat to burn the fuel completely at idle. Big rigs are a different story though.
 

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Discussion Starter #4
He use to let his 7.3 powerstroke idle all night with the heater on to stay warm when we would go camping. Maybe thats why he had so many problems with it.
 

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other than it being a ford??:rof J/K didn't the 7.3 have auto high idle? How cold was it when he was camping?
 

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it would range from lows in the 50s to lows in the 30s. The truck had a high idle but it only came on when the truck was cold. It was a POS he never really took care of it.
 

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Well, being a POS and not taking care of it goes hand in hand. I have a friend that has a 7.3 and it does pretty good. There is no reason to let a vehicle idle (even for heat) until it is below 0.....that's why they call it camping. I have let my truck run almost all day on an occation or 2, but I activated the high idle during that time too (I wired a manual high idle on mine). The temp out that day was about -30F and I was running all over that day and couldn't plug the truck in. It is ok to let it idle for 15-20 min, but don't do it for hours unless it is cold outside. The new trucks have the auto high idle feature for those times anyway.
 

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well.... i've been told that letting them idle long periods washes the cylinders down. a lot of people have said to keep it under 15 minutes of idle time unless you can get the engine up over 1000 rpm for the idle time.
I agree 100% with skeeterkilr.:thumbsup
Efilive can adjust your idle settings, and I believe you can also use the PTO input pin on your PCM to control your idle with a switch.
If you need to idle your truck and need this done, I can help you with it if you would like.

Anyway if you have any questions about it let me know

Thanks,
Josh
 

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well.... i've been told that letting them idle long periods washes the cylinders down. a lot of people have said to keep it under 15 minutes of idle time unless you can get the engine up over 1000 rpm for the idle time.
I agree 100& with skeeterkilr:thumbsup

LLY's don't have a switchable high idle like the LB7's

The LLY's PCM is programmed to enable the Elevated Idle when the following conditions are met: Engine coolant must be above 5 F and below 145.5 F
and intake temp must be below 41.5 F.
when enabled it elevates idle speed by 80 RPM every second until it reaches the desired idle speed of 1200.0 rpm.

Efilive can adjust the idle settings if needed, if you plan on letting your rig idle you probably want to bump up the normal desired idle speed.
Below is the stock desired idle speeds

Stock Desired Idle Speed
( F ) RPM
-40 850.0
-18 850.0
3 800.0
25 750.0
46 750.0
68 712.5
90 690.0
111 680.0
133 680.0
154 680.0
176 680.0
198 682.5
219 690.0
241 697.5
262 710.0
284 727.5
306 750.0
 
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