I fully understand the high idle features on my truck, but over the weekend it did something it never did before. I was up north, New Hampshire, and it was pretty cold, about 5* and it was not plugged in(no outlet or cord). The truck usually startes up and idles at 750 rpms, then when the grid heaters stop cycling, it will go to auto high idle, 1000 rpms. But this time it went right to 1000 rpms instantly. (both mornings)

anyone every have that happen to them?

 

My truck does it also mainly when it real cold and not plugged in

 

It happens to me all of the time. Sometimes when it's -30 F it will actually rev to about 1500 RPM and then surge the idle between 1000 and 1500 until it settles to 1000 RPM.

 

hum, that's interesting.

i guess i was never in a cold enough environment to have that happen.
i couldn't imagine -30* startups

 

It is perfectly normal and designed to do this when certain conditions are met. You will also notice the engine noise is much louder when this happens. I believe the pilot injection is defeated, making it sound almost like the Gen IIs.

 

I noticed mine did this about 2 weeks ago. It was the first time I had ever heard it do it, but I knew what it was when it did it from reading about it here.

Funny thing though.........the temp was only about 20 degrees and real windy. And, what surprized me even more is I had driven the truck about 25 miles (so it was up to normal operating temp) and was stopping to get fuel but left it running. It just idled up on it's own to 1000 rpms. I also noticed that I could not use the high idle feature using the cruise control buttons while it was doing this.

Anyway, after fueling I just rolled on and no problems.

 

You should still be able to use the Cruise Control settings to manually bujmp up the idle to 1100 - 1500 rpm. At least on mine I can still do it. Being in Vermont, it has been cold lately and mine rev's right up to 1000 like designed. Even after driving miles, if I let it still at idle for a few moments, it will idle up by design. Sure hope it gets warmer soon.

 

My 03 has done this once, I about went through the roof. I spoke to a mech. at the dealer in my home town about it and he claimed it was normal. Not that I trust his word, but that's what he claimed. ?????????

 

Normal, Normal, Normal, it helps heat the engine and it keeps the alternator spinning enough to enable the grid heaters to stay on. When starting and when Idling keep all other drains of current on low or off to enable the grid heaters to get full power. Full heater, subwoofer and seat heaters on plus grid heaters is a draw. I turn the fan down, the stereo off and the passenger seat heater off. There are limits ya know. ks

 

how do you use the cruise control buttons to speed up idol?

 

I believe the automatic ramp up was designed to more thoroughly combust the fuel, reducing pollutants. The design also prevents diesel wash which is hard on the engine. An added bonus is that it helps to heat the engine also reducing pollutants and giving us much needed cab heat.

 

It's easy to use the high idle feature (as long as it's enabled: If it's not, go to your dealer and ask them to enable it with the DRBIII. If they don't know how, it's under engine and it's under transmission. Just scroll down to 'enable high idle feature' in either section).
Your foot has to be off the brake and stay off the brake; just put on the park brake. Transmission has to be in park or neutral.
1. Turn on the cruise
2. Push 'Set'
3. Pushing 'Accel' should ramp it up from 1100 rpm to a max of 1500 rpm (Using 'Decel' will bring it down from a max of 1500 to a low of 1100). If you just tap either button, you should get 100 rpm change for each tap.
4. To turn off: Just tap the brake pedal, turn off the cruise, hit cruise cancel, or drop it into gear (if you do this slowly, basically just moving the gear shift around in neutral it will give the ECM time to drop the rpms before you LAUNCH your truck. You will know when you have moved the gear shift enough as the rpm will drop fast, even though the transmission has not engaged yet).
DC only wants the auto trucks to have this feature. It can be enabled on manuals, it just takes a bit more to get it to work...... I am still finding out if they will just enable PTO control so it will do the same thing.
Dan

 

When it's really cold out (Below about 15F, I think), you guys may have been hearing the motor start on 3 CYL's . It is programed to do it, but I'll bet it is pretty wild sounding. Mine has only done the instant 1000 rpm thing. I could not get it to stop it either. Usually all you have to do is press the brake pedal. The only way I could get it to slow back down was to put it into gear. I just don't like reving a cold motor up that much. Give them a little time to warm up gradually (at least wait till the oil has started flowing around).
Dan

 

thanks, i'll try it

 

The Gen IIIs do not shut off any of the cylinders. That was a Gen II feature.