WILDEBILL308 wrote:
Not hard to understand. When you start a cold engine and after oil pressure comes up when you go to fast idle the additional boost provided generates enough heat to get more complete combustion of the fuel.
"But here's what Cummins told me directly. My engine has a warm up protection feature that won't allow me to fast idle or use the throttle until the engine is ready to perform and everything is up to pressure and temperature to prevent harm. This is what's coming directly from Cummins."
Well that is easy to check. I bet starting with a cold engine, as soon as you can go to fast idle you can drive. It won't be at operating temperature.
Bill
I think I understand your point and I agree completely. If I understand you correctly, you are saying that a slow moving piston (base idle) provides just enough compression to ignite the diesel fuel in the combustion chamber, but not enough to get complete combustion, especially in a cold engine. While a faster moving piston (high idle) will generate more heat immediately and provide better combustion. If that is what you mean, that makes a lot of sense to me and supports my current belief that "best practices" are to start the engine and get it into fast idle as soon as the oil pressure is up or in my case, as soon as the computer allows it to go to fast idle (10 seconds, max (computer monitors oil pressure)).
The second point you mentioned was that the engine won't be at operating temperature and I also agree with that statement, but I wonder what does "operating temperature" really mean? Does it mean that you shouldn't engage the drive components while it's below operating temperature? Does it mean that the exhaust system won't work optimally? Does it mean that you shouldn't try to get maximum HP out of the engine during an acceleration to the highway? Or all of the above?
I seem to remember my dealer telling me there is no longer a warm up period. i.e. once the oil pressure is up, get going. Idling is worse than driving. Maybe this is the new "best practices."
