Just doing some reading and I noticed the sticker on my visor said that in cold conditions you're supposed to crank the enginer, raise the RPMs to 1,000, and then let it idle for 30 seconds. I've always been one to let my engine idle for a little while in cold weather just so it could warm up good....but what's the reasonining behind raising the RPM's to 1,000 and then letting it go back down to idle??

 

Maybe to bring up oil pressure faster ???<br>DM01

 

When I ask a question I expect an answer!! ;D

 

to make sure your right foot is operating properly so you can drive the truck and stop asking all these questions........

 

This is to aid in building heat faster, if a diesel idles too long and cylinder temp drops down this can cause &quot;slobbering&quot;, or the seepage of oil past rings because of low combustion pressures. Once it gets good and warm it will be a lot less prone to slobbering.

 

[quote author=spots link=board=20;threadid=15170;start=0#142771 date=1054085313]<br>to make sure your right foot is operating properly so you can drive the truck and stop asking all these questions........ <br>[/quote]<br><br>Panties in a wad?? ;D :P

 

[quote author=bneaves link=board=20;threadid=15170;start=0#142814 date=1054089674]<br>This is to aid in building heat faster, if a diesel idles too long and cylinder temp drops down this can cause &quot;slobbering&quot;, or the seepage of oil past rings because of low combustion pressures. Once it gets good and warm it will be a lot less prone to slobbering. <br>[/quote]<br><br>That would make sense if you were to HOLD it at 1,000 RPMs for 30 seconds...but it says to raise it to 1,000 RPMs and then let it return to idle and then idle for 30 seconds. I understand the reasoning behind raising the RPM's, but the cold start instructions that came with the truck don't make any sense. ???

 

[quote author=Hoss link=board=20;threadid=15170;start=0#142940 date=1054126286]<br>[quote author=spots link=board=20;threadid=15170;start=0#142771 date=1054085313]<br>to make sure your right foot is operating properly so you can drive the truck and stop asking all these questions........ <br>[/quote]<br><br>Panties in a wad?? ;D :P<br>[/quote]<br><br>U been peeking???????? <br>Thongs u'll do that......

 

Hoss, <br><br>No Question is Dumb, Only Dumb people who don't ask any Questions. In my 33 years teaching in high school this was my Motto I gave to students. Those who learn when we ask questions of ourselves and others.<br><br>When a cold engine starts the injectors are more prone to fouling at idle speed. Raising the idle causes the injectors to prevent fouling. This is why if continues to idle for long periods when ambient temp is 32 degrees or below, the ECM automatically raises the RPM above 1000 to prevent fouling and speed the warming of the CTD. <br><br>Don't let em give you any lip, Hoss.

 

I run mine at 1500 rpm for about a minute to 3.<br><br>The grid heaters will turn off once cyclinder temperature hits the proper level it seems.<br><br>Most notably is if you hold the 1500rpm and the grid turns off the engine will cycle from 1500 to 1700 rpm about 5 times (keep your foot steady) and will also quiet down when it finally settles in on the 1700rpm level (no load).<br><br>Keep on trucking.

 

[quote author=Sierra Phil link=board=20;threadid=15170;start=0#143004 date=1054134465]When a cold engine starts the injectors are more prone to fouling at idle speed. Raising the idle causes the injectors to prevent fouling. This is why if continues to idle for long periods when ambient temp is 32 degrees or below, the ECM automatically raises the RPM above 1000 to prevent fouling and speed the warming of the CTD.[/quote]<br><br>So basically the truck will take care of itself?? The only thing that confused me was the procedures for cold starting on the sun visor. It said to raise the RPM's to 1,000 and then let it return to idle...and then let it idle for 30 seconds. Had it said to HOLD the RPM's at 1,000 for 30 seconds then it would make sense....but what good does it do to raise it and then just let it drop back down?? THAT is what doesn't make sense to me. <br><br><br><br> ;D

 

[quote author=Hummin' Cummins link=board=20;threadid=15170;start=0#143024 date=1054136915]Most notably is if you hold the 1500rpm and the grid turns off the engine will cycle from 1500 to 1700 rpm about 5 times (keep your foot steady) and will also quiet down when it finally settles in on the 1700rpm level (no load).
[/quote]

Interesting you mention this because mine won't let you hold an RPM level. I noticed the other day while trying to hold it at 1400 RPM's just for the fun of it that even though my foot was steady it would cycle up and down between 1400 RPM's and about 1200 RPM's (this was in the middle of the day after I'd already driven about 15 miles and had stopped for lunch). Couldn't figure that out either...but didn't see it as anything to question about.

I won't have to worry about cold starting very often....but the instructions for cold starting on the visor just didn't make any sense. I think I'll just pull them off and forget about it.

 

The reason for increasing the rpm,s on a cold start (very cold weather) is to keep the engine from stalling. It also helps to insure that all the fuel injected is burned. The unburned fuel will wash the oil from the cylinder walls and will contaminate the oil.

 

I repeat:<br><br>