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View Full Version : Why do you want a higher idle speed?


dcmsu
06-12-2003, 16:52
I have been reading and searching, and have figured out HOW to set up the high idle, but still am unclear as to WHY one would want a higher idle speed.

Dan
NWDmax
06-12-2003, 17:15
Faster warm ups in colder weather is the reason I put it in.
mackin
06-12-2003, 17:40
I use mine also to speed up turbo cool down ,prior to shut down ....

Mac http://forums.thedieselstop.com/ubbthreads/images/graemlins/shrug.gif
britannic
06-12-2003, 19:35
The high idle speed ranges can be used to run the PTO from the transmission where fitted.
FirstDiesel
06-13-2003, 04:22
And then there is the real reason. Some just have to have all the toys available! :D

Really, how many here are running the PTO?? :rolleyes:
c5dura
06-13-2003, 06:33
I use high idle when running my 15000# winch to keep the batteries charged.
SparkyTX
06-13-2003, 07:29
Very common reason for higher idle is to power high drain accessories, like winches, stereos, etc while stopped.
sdaver
06-13-2003, 07:31
BECAUSE WE CAN HAVE ONE......
smitheb
06-13-2003, 07:41
How do you activate the higher idle speed?
hoot
06-13-2003, 11:04
You install a switch that appliies 12V to a specific terminal on the computer.

When you turn on the switch, the cruise control turns into the high idle control.

When you turn cruise on you get first stage I believe 800rpm

Hit resume, 1200

Hit Set, 1800

This is 2001,2002 only. They changed in 2003.
a64pilot
06-13-2003, 11:06
Higher idle get the A/C working good, also just the ticket if I have to jump start one of the tractors or backhoe etc.
DrL30047
06-13-2003, 11:20
Everyone go ahead and laugh, but here goes. Can the High Idle Switch be used to keep the D/A running in the Summer with the A/C on for pets left in the car for short periods, say 45-60 minutes?

Where can you get them installed, for those of us who are mechanically ignorant?
mackin
06-13-2003, 14:24
Originally posted by hoot:
You install a switch that appliies 12V to a specific terminal on the computer.

When you turn on the switch, the cruise control turns into the high idle control.

When you turn cruise on you get first stage I believe 800rpm

Hit resume, 1200

Hit Set, 1800

This is 2001,2002 only. They changed in 2003. The change was in 02 as the 02 only gets the two higher levels that I've seen ... There are issues with the balance rate when Tech II is used to set lower setting as the 01 has...


DrL30047

It's quite easy to install...The dealer is capable if you want to pay the bucks ...

Mac

[ 06-13-2003, 02:32 PM: Message edited by: mackin ]
dcmsu
06-13-2003, 16:31
So basically the high idle is for faster warm up in cold weather. How much of a difference does it actually make? Is it bad to idle the truck a lot? I have been keeping it running if I just run into the store or something (of course I lock it though) Just was wondering if this is good or bad for it. Usually I idle it for 15 min. but it has been for as much as 45 min. If I am loading up a trailer or something.

Dan
mackin
06-13-2003, 19:58
Originally posted by dcmsu:
So basically the high idle is for faster warm up in cold weather. How much of a difference does it actually make? Is it bad to idle the truck a lot? I have been keeping it running if I just run into the store or something (of course I lock it though) Just was wondering if this is good or bad for it. Usually I idle it for 15 min. but it has been for as much as 45 min. If I am loading up a trailer or something.

Dan For me in the winter with the winter front on it makes quite the difference in warm up time ....To melt snow and or ice,frost ....

IMO Your idle times are within reason,nothing to be concerned with ..... I will idle more in the winter then any other time of the year ....

Mac
dmaxstu
06-15-2003, 14:37
When I drove trucks up in Calgary Alberta Canada many years ago I worked for Kingsway Transport they owned the trailers and owner/operators owned the tractors. Sometimes the rigs would arrive in the evenings and were due out after about 8 hours. During the winter (-40 degrees) these tractors would be parked outside on fast idle.The main reason was that the upper part of the 3engine would be starved for oil if not run at about 1000RPM besides keeping them from freezing up. Older GM diesels were notorious for low oil presure hence fast idle options. I notice that our Dmax has very high oil presure compared to past Gm diesels and I wonder how necesary the fast idle option is. IE the fast idle is mainly for maintaining oil presure during idle and thus a diesel engine could run for a day on fast idle without ill effects. Stu

[ 06-15-2003, 03:31 PM: Message edited by: dmaxstu ]
a64pilot
06-17-2003, 09:14
Diesels that are idled at low speeds for long periods of time will "stack" or "slobber". In other words the engine will cool to the point to where all of the fuel is not burned and will build up in the upper cyl. It washes off the oil from the cyl. walls, dilutes the oil in the crankcase and generally makes a mess. This is one reason why you see the big rigs smoke like the Devil when they start off after sitting for a while at truck stops etc. If a Diesel is idled for long periods of time the oil temp may drop to the point that impurities are not boiled off.
IMHO for short periods of time < 45 min or so let it run, any longer if you can shut it down.