I know there are plenty of threads out there about the "High Idle" mod but I couln't find the answer to my question..
Is it bad to have the truck startup to 1200rpm first thing in the morning vs regular Idle?
Right now I let the truck Idle at stock idle for about 5 minutes each morning.
So I am hoping the High Idle will help the truck warm up better and not do anything harmful to the engine when its cold.

Thanks

 

Usually a couple of minutes at idle is fine, normal cold weather strategy would up the idle after a few minutes as well so I think you are fine.

 

I am interpreting your question as you'd like to cold start your vehicle using the high idle mod where it goes directly to 1200 rpm. If so:

I've always been told that the greatest engine wear occurs at engine start up, before the engine oil can flow and coat everything. Oil pressure seems to stabilize within 30 seconds per the gauge (on a vehicles with oil pressure gauge) but I am not sure that is enough time for complete oil circulation. That being the case, I think the lower the initial idle the better. After oil circulation for two minutes or so, I think the idle can be safely increased to 1200 rpms. Bear in mind, this is all temperature and oil flow dependent. The colder it is the worse the cold oil flow. Synthetic oil flows better when it is cold.

I think this is how/why the cold idle strategy works the way it does as Senix alluded to.

I haven't had my 6.4 in the cold yet but my 7.3 is a bear to start when it is 30 degrees and colder with 15w-40 and no engine block heat. It just romps away until it gets warm enough to idle. Then it takes a few minutes for the cold idle strategy to increase the idle to 1200 rpms. Switching to synthetic 5w-40 made a huge difference as well as plugging in the engine block heater for a while.

Reminds me, I have to buy and install a engine block heater cable on my 6.4 before winter.

 

I think this matches the starting instructions

key on, wait for glow plug light to go off
start
idle for 15 seconds
drive

Sam
diesel supplement, page 12 under Driving
1. Turn the key to on without turning the key to start. Do not start the
engine until the glow-plug pre-heat indicator turns off.
2. When the glow plug pre-heat
indicator turns off, turn the key to
start, then release the key as soon
as the engine starts. The glow plugs
will continue to be activated for two minutes after the glow plug pre-heat
indicator has turned off. If the engine is not started before the
glow plug activation time ends, the glow plugs will need to be reset by
turning the key to off.
3. After the engine starts, allow it to idle for about 15 seconds. This
is to protect the engine. Do not increase engine speed until the oil
pressure gauge indicates normal pressure.

also, for specific cold weather, the system will protect itself.. from the diesel supplement page 11, cold weather starting strategy

Your vehicle may be equipped with a cold weather starting strategy that
prevents severe engine damage by assisting in engine lubrication
warm-up. In extremely cold ambient temperatures, this strategy activates
and prevents the accelerator pedal from being used for 30 seconds after
starting the vehicle. By not allowing the accelerator pedal to be used, the
engine oil is allowed to properly lubricate the bearings preventing engine
damage due to lack of proper lubrication. After the 30 second warm-up
period, the accelerator pedal will be operational again as long as the
pedal is not being pressed when the 30 second time limit expires. When
starting the engine in extremely cold temperatures (-15°F [–26°C]), it is
recommended to allow the engine to idle for several minutes before
driving the vehicle.

 

Let me tell you, I have started mine as low as -1F without the engine block heater (was at a hotel in Kanas or something). It is loud and makes alot of noise for a minute or two. I let it run for about 2-3 minutes then kept my speed low for a couple miles.

 

Thanks for the great information guys. How would I know if the oil pressure is normal since there is no gauge for it? But I got this figured out.

Cheers

 

I remote start my truck with high idle switch on ,set brake, it will idle up after temp,timer lets pedal operate! I use block heater all the time! I think it so much better for motor!

 

I agree with the idea that 1200 rpm at start up is prob not a good idea if it's below freezing and no block heater is used.

The PCM will elevate the idle if the engine oil is below a certain temp (I forget what the temp is but it's something like 46F.) The elevated idle will not execute until the motor has idled for a minimum amount of time, probably 1 minute or something. You will know when the temps drop for you, probably very soon up there.

I would not activate your 1200 rpm idle since the engine will do it automatically anyway. During the day I have used it to keep the engine as warm as possible, it cools down quick at idle when it's really cold outside.