Cold Idle RPM

[Cthusker]

Just had my 5000 mi service done by my dealer. After reading all the posts on syn oil I changed to Mobil 1. I'm sure there are better brands but it's what the dealer has in stock. Anyway my question is what should the COLD idle RPM be? Mine seems a bit high (around 1350) which is annoying until the truck warms up. I have large hill I go down and the idle is high enough that when I'm in a hurry the anti lock breaks engage when I have to stop at the bottom of the hill. I did ask the dealer to check the idle and he said it was ok! Said they tend to run a bit high..... and it's computer set. Just wondering what others experience is with cold idle....

 

[Boaz]

Sounds normal to me. I always give my runner about 1-2 min to warm up reguardless of the temp. I know what you mean about the antilocks when its idling high.. just give it a extra min or 2 to warm up in the mornings.

 

[greasefingers]

Here are some numbers for you to compare. The outside air temp = 86 degrees F. HVAC controls turned Off. Start the V8 and let idle. Record rpm vs time: On initial start up the rpms spikes to 1600 and instantly settles to 1450.

2 seconds = rpm 1450
2 minutes: rpms = 1000
3 minute: rpms = 900
4 minutes: rpms = 800
5 minutes: rpms = 750 Temperature is entering that funny window section
8 minutes: rpms = 700 Temperature is 1/3 of the way into funny window section

The FSM manual states that the idle speed should be 700 rpm +/- 50 rpms

 

[Cthusker]

Thanks..

greasefingers..... that's exactly the info I need. I appreciate the help. That will be my little project today to see where my idle numbers fall.........