Posted by Sherman in Idaho [108.162.246.17] on Sunday, October 23, 2016 at 10:08:47 :
In Reply to: Re: O.T. "high idle" / "low idle" on an old posted by TGP (IL)ip [172.68.58.145] on Sunday, October 23, 2016 at 03:25:46 :
So, I would set "high idle" to 1400 because that's the torque peak? Strange that they'd call it "idle", and also confusing because the "low idle" is supposed to be set to 550 at the "tach adapter" which is driven at camshaft speed. Maybe back in the day there was a special Caterpillar tach that read half the rpms that it was actually measuring, so 550 was truly the crankshaft speed? That would be about right. Looked through all my old manuals and googled it every which way and can't seem to find a clear answer. Maybe I'll just go by what sounds right. Don't want to blow the engine up, though, and also don't want it any slower than necessary because D4s barely have enough power to push themselves up a steep hill much less push dirt up.
But I appreciate your answer that "high idle" is really just the high speed limit.