Cold weather and high idle
 

My truck will kick to the high idle even after it has been driven and is warm. It is cold out, in the teens, but should it do that even though the water temp is near 200?

Yes it will....Even though the engine is warm, when it is that cold it wont take much to cool it back off. Its just doing it to keep itself warm.

Cylinder temps drop dramatically when a truck is idling. I have had mine kick up to 1000 rpm's in the summer. It's normal

kev this is happening because even though your coolent is warm, ideling is one of the worst conditions on an engine because of the fact that your gettin way more fuel than air. a rich condition like that creates very cold cylinder temps, your engine is bringing your rpms up to burn that fuel with more air and heat back up. just because your rpms go up dosnt always mean your injector pulse width is being lengthened.

plus in the states that we are in now its cold as all get out and our engines are VERY cold! unlike back home and in georgia. i was worried about mine too when i first got up here because it was doing the same thing, but i found out in class that it is normal.

Extended idle operation, especially in cold weather, can lead to stuck valves and bent push-tubes due to insufficient cylinder heat. This allows varnishes/oils to condense on the exhaust valve stems, leading to stuck valves, and damaged valve train components. A new software feature, enabled or disabled through the DRB III reduces the chance of valve sticking and improves cab heat warm-up time. Once enabled, idle speed will slowly ramp up from 750 rpm to 1200 rpm when all of the following conditions are met:

1. Intake Manifold Temperature less than 0°C (32°F) and,
2. Coolant Temp is less than 60°C (140°F) and,
3. The Transmission is in Neutral or Park and,
4. The Service Brake pedal is not depressed and,
5. Throttle = 0% and,
6. Vehicle Speed = 0 mph

Additionally, if Intake Manifold Temperature (IMT) is less than -9°C (15°F), and all of the parameters above are met, three of the cylinders will be shut off upon reaching 1200 rpm, creating a slight change in engine sound which is normal. This allows the engine to create increased heat in the cooling system, allowing more rapid engine warm up and cab heating.

Jason

I wasn't aware of 3 cylinder idle on a 3rd gen?

dslpwr81

I'm pretty sure that info is for a 24 valve, not CR. It's the same principal though. The CR only idles up to 1000 rpm, and I have never experienced a 3 cylinder idle like the 2nd gens have.

Regardless, I generally manually set my idle at 1200 rpm's when I stop and know i will idle for more than a minute or 2.

Disregard the 3 cylinder Idle on the previous post. It was a copy past from Geno's. Just a quick post of the purpose of high idle only, thats all. And you are correct, there is no 3 cylinder idle or 1200rpm.

The truck isnt being idled in excess. I notice it when I pull in to park, the truck doesnt run for extended periods of time. Thanks for the info.

Mine high idles after driving in cold weather. It will kick up a minute or so after I park it depending on the outside temp and engine temp.