effects of pilot and post injection

[cjowett]

Just wondering if anyone can tell me the effects of pilot and/or post injection with respect to cold weather tuning. My experience has been that diesel fuel economy goes out the door when the weather turns cold so I'm hoping that I can use the alternate tables to improve things but I need to know what to change. Timing is probably one thing. But pilot injection might be something else.

[2007 5.9]

Are you looking to disable Pilot/Post or just better utilize them for MPG?

[cjowett]

Certainly don't want to disable it. Looking to improve cold weather MPG.

[2007 5.9]

Most of my best mpg tunes are single injection events and start and run very well in cold weather.

[2007 5.9]

Likely to improve mpg in a multi event tune, you'll need to log your cruising area and start to add main timing until desired mpg is either achieved or the is Rattle. You could add pilot timing but care must be taken to not inject too soon and become a hindrance more than a help

[cjowett]

So what about adding pilot and/or post volume? From what I understand the way the tables work is the pilot and post volumes are a portion of the total demand. So would adding volume to one or both allow more fuel to be burned in a hot environment? Or would it be subtract some from pilot and add it to post. I'm talking a little not a lot. When I say mileage goes out the door its about a 25% drop so obviously the amount you would move off main injection would something less than that. I'm guessing not more than a 5% shift, coupled with timing tables that are intake temperature sensitive. The problem with targeting mpg figures is that it really takes an entire winter to know if you've been successful because there are so many other influencing factors how far you go on one tank of fuel. Hence it's not something that I want to just try aimlessly. I'd like to know the real purpose behind each event I guess.

[cjowett]

Oh, and by the way, thanks for your input Les.