High Idle - Why?

Running a company truck now and always hated idleing with my own truck but my boss don't believe in apus so when I go to bed the big Cummins goes to 1000 rpm and the unit goes on continuous.

 

Not true.
I idle during freezing or baking temperature, but my pto idle is only 720 max.
The only time it goes higher is during a regen.
If trucks were set correctly at the shops, you would rarely have to exceed 700-800 rpms for pto.
That range gives a nice smooth running engine and everything works correctly.
With the older engines that are without the newer electronic control units, the newer regen systems, etc., 1000 rpm or higher is necessary.

 

High idle to me a anything you have to set at that rate. Mack and Volvo both want the idle to be set at 800 rpm to idle over night. Same holds for all the others so yes it is true.

 

My Volvo is set to run pto between 700 and 725 per Volvo.
But even at 800, that is still smooth and consistent.
I think he was referring more to those trucks that idle higher, then wind up and down all night.

 

I'm driving a 1998 Cat Luckily, I don't live in the truck, but.... If it's really cold out, and I can't plug it in I idle it at night while I'm at home. Do I need to high idle it? I'm not in it. I don't care if it's not "toasty" inside it while I'm at home. Am I hurting it if I don't high idle it? Because I save fuel if I don't.

 

I don't now much about cat engine. Detroit Diesel tech said on S60 it was hard on the injectors to idle at low RPMs because it loads a lot of fuel in them. He claimed they were designed to run at full power all the time. That why they could go 700,000+ miles. On my S60 and most you would get unburned diesel on exhaust and it would smoke like crazy first mile. How much of that undurned diesel got past piston rings I don't know. That was the idea back then. Today you could take oil sample and see if any diesel is in engine oil.

 

You should probably higher idle yours too. Don’t wear your truck out.. unless you work for a company then I can see why you wouldn’t care.

 

That's a great attitude. Why would you care about the piece of equipment that makes you're paycheck. SMH. Thanks for reminding me why I will never have employees. Because of guys like you with you're "I don't give a sh!#$ its not my truck" attitude.

 

My 2000 truck with 1999 S60 has the Detroit Optimize Idle. I took oil sample back then and found almost no problems letting the truck idle. The wear on the engine was only like 5 parts per million less. It would idle at 900 RPMs when the computers did it. That was enough to keep the engine warm like 170F.

I'm driving a 2017 truck and it has same Optimized Idle it still idle at 900 RPM. If someone is going to idle engine I don't see why not idle at 900. You avoid any possibility of low engine temp and you don't really save any fuel in my opinion. Plus if it really cold you need heat to keep the fuel warm also.

 

Company have our trucks set up to shut off after 3 minute of idling unless fast idle set. Fast idle in my truck is only 800rpm. Previously trucks had been set anywhere from 1000 to 1200