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General Boards => Technical Support => Topic started by: Mike Groves on April 06, 2016, 01:48:22 PM

Title: C12 Idle RPMs - What is yours?
Post by: Mike Groves on April 06, 2016, 01:48:22 PM

All,

When I got my '99 Marquis the idle was set at 800rpm.  I think I read the CAT documentation and 700rpm was advised.  Maybe that's a false memory as to where I found the information, but I did use the Silverleaf to change the idle to 700rpm.  What are others using as a slow idle?  When I start it, it has always started right up, idles high for a little bit, then goes down to 700rpm.  At that point I usually use the cruise control to raise the idle higher (about 800-900) as it warms up.  Then before I move out I turn off the cruise which then cuts the idle back to 700rpm.  Any suggestions on a different technique or different idle speed?

Thanks,
Mike

Title: Re: C12 Idle RPMs - What is yours?
Post by: Dave Atherton on April 06, 2016, 09:53:04 PM

Mike there has been a Cat service bulletin on C-12 engines not charging at low idle
At 600 rpm and many alt been changed out for this reason. Increasing rpm between
700 and 800 rpm will correct problem. Dave Atherton Retired Cat Mechanic

Title: Re: C12 Idle RPMs - What is yours?
Post by: Mike Groves on April 06, 2016, 10:05:44 PM

Dave, I've never tried mine at 600, so 700 it is.

Mike

Title: Re: C12 Idle RPMs - What is yours?
Post by: Jerry Emert on April 06, 2016, 11:00:18 PM

Mine runs around 700.

Title: Re: C12 Idle RPMs - What is yours?
Post by: Dave Atherton on April 07, 2016, 01:38:04 PM

Jerry, I like the way you put your model engine and engine S/N number on bottom.
This would be a good suggestion to everyone that needs some advise on a Cat problem.
So many times have to ask question ( what model engine and engine S/N number ).
To help answer many questions the S/N again very important.
Dave Atherton Retired Cat Mechanic

Title: Re: C12 Idle RPMs - What is yours?
Post by: Jerry Emert on April 07, 2016, 02:19:14 PM

I did that for you Dave!!