Cold Weather Start ,1000 RPM Instant!
 

I have found in extreme cold weather{ o.k. so so cold below 10F}
my truck upon start up instantly jumps to 1000 rpm, no 2 minute time delay. Now of course that when I have not plugged it in. Normal?

Somtimes they do this, other times not. Mine has seen -10 F and didn't do it while at 20 F it did. [eyecrazy]

Mine will go right to 1000 RPM if the temperature is below 15 F and not plugged in.

If all the cold weather parameters are met, it will immed go to the 1000 rpm plugged or not.

-24°F today, fired right up, hit 1K rpm instantly.
Had it plugged in, but outlet was faulty.

Mine will do the same thing. One dealer told me its normal, another said it is not normal. The dealer that told me it is normal says they run up to 1000 rpm like that to hold the oil bypass valve in the pump slightly open to stop it from chattering. Oil pressure on mine comes up immediately or at least the guage that registers oil pressure "according to customer expectations" says it does.:D

Brian

Six degrees this morning, truck plugged in. It goes to 1000 RPM after two minutes. Perhaps it has to be colder than it has been here to ramp up instantly when it is plugged in.

Re: Cold Weather Start ,1000 RPM Instant!
 

Mine did this the other day at 23 degrees, but not the next day at 9 degrees. Me thinks there is a minor bug in the programming :)

drove to missouri yesterday pm went down to 18 ,fast idol came on and remained on during my rest stop.....then as the day went on the temp came up to 23,and the high idol would come on like clock work when i stoped but didnt stay on....i wonder where the sensor is...if you coukd find it then it would be possible to override it and make it come on and stay on when u want it,and do away with the stick .....the high idol is nice when it stays on

It is suppose to shut off when the engine gets to a certain temp, when the engine temp falls again it will come back on.

when it was 18 it stayed on

If it is cold enough the engine temp never get up enough to turn in off. If you had an exhaust brake to run with it you would see it turn off and on more.

My 1,000 RPM fast idle has never come on right away and we have had below 0 temps several times over the last two weeks.

It always takes 2 to 3 minutes before it ramps up, it will do the same thing if I knock it off, drive a short distance where the truck does not acheive normal operating temp and let it idle in 2 or 3 minutes the fast idle will ramp up again. the first time that happened I had gotten out of the truck and walked maybe 25 yard away from the truck, it stopped me right in my tracks.

I thought maybe it waited the initial 2 or 3 minutes after starting for the grid heater to do their thing first before turning on, just a quess though.

Mine has gone right to high idle some times, but it seems to have no pattern of when it will do it. This morning it was -15 and it didn't go right to high idle so it isn't temp.

I am certain there are other factors other than temperature, there are probably other sensors that need to offer feedback in a certain range before the high idle is engaged. When it's very cold the high idle can take a bit of time before engaging, I'm sure that the DC/Cummins engineers have a good reason but it's too technical to be included the user manual.