What do these do/mean? Pilot 1, etc.
I'd like to get a better understanding.
What do these do/mean? Pilot 1, etc.
I'd like to get a better understanding.
Its how they made the diesels quieter. Short fuel pulses as piston travels up.
But what do the different ones do? I'm guessing each pilot squirts fuel at a different time?Originally Posted by mecanicman
This is what the GM book says about it:
The fuel injection control utilizes a pilot injection method to reduce the combustion noise that is common in traditional diesel engines. The pilot injection method reduces noise by supplying a small amount of fuel to the cylinder just before the normal combustion timing.
don't mess with the pilot injection tables. You can zero out the post-injection tables.
2006 LBZ Duramax
5" Magnaflow turbo-back
EGR blocked
HP Tuned by yours truly
1 pilot is the basic pilot injection to reduce the rattling effect. Basically, it creates a little bit of pressure on the piston as it's rising to TDC in the power stroke. The other 1 or 2 pilots are "adders" which increase the amount of the pilot injection based on other variables like air temperature. Tuners in various parts of the US might find it useful. The post injection is for the purpose of adding heat for the DPF or catalytic converter to burn the noxious gases in the exhaust. I've messed with them before, and there is nothing to be gained. I agree, zero out the post injection, but you have to off the DPF. Say you make a 20% reduction. Maybe you get more rattle maybe not, but compared to the main injection your percent change is less than 1%. It's not going to make a difference in fuel economy. Say a person is thinking of making an increase. They'd be better off moving the percent pulse width BTDC by 1 or 2 degrees.
2005 Silverado 3500
LLY Duramax
Replaced injectors @ 128k miles
Removed EGR
PCV reroute
LBZ turbo mouth piece
3" intake bridge with 3" intercooler piping
LBZ injection pump
Custom GT4094VA
Custom 3.5" down pipe
Boost and EGT gauges
Where are the post injection tables? Are they labeled that way or something else?
Explain this a little better, please
Are there any tuning books available for diesel rigs?Say you make a 20% reduction. Maybe you get more rattle maybe not, but compared to the main injection your percent change is less than 1%. It's not going to make a difference in fuel economy. Say a person is thinking of making an increase. They'd be better off moving the percent pulse width BTDC by 1 or 2 degrees.
You haven't stated which engine or what year you're tuning. You're an "Advanced Tuner"??? ...of what gas engines??? Member for 4 years already??? I mean, come on, you're killin' me here man. This is stuff that every tuner here has dealt with on their own. Ask a complicated question. I was trying to give you an example of why not to change the pilot injection. If the engine you're tuning has post injection, you can zero it out as long as you're going to address the DPF issues. My suggestion to you is to read and research what they are.
2005 Silverado 3500
LLY Duramax
Replaced injectors @ 128k miles
Removed EGR
PCV reroute
LBZ turbo mouth piece
3" intake bridge with 3" intercooler piping
LBZ injection pump
Custom GT4094VA
Custom 3.5" down pipe
Boost and EGT gauges
I've done thousands of gas tunes and have no issues there. I'm trying to do some diesel stuff and while some of it seems like I'm reading into it, it's all Greek to me. I've read lots of informative threads and posts by those that seem knowledgable. But I've also read LOTS of threads where it's a novice asking for help or to look at their tune. The good information gets lost in that. If you have some threads book marked that you think are A1 choice threads, PM me or post them up and I'll go read them.
As for year, I'm asking in general. The several I've looked at all have pilot injection. I know a little of the theory behind the pilot injection, but none of it says anything specific about what each does and when they are active.
Your sweating the small things. Dont worry about pilot, it wont make or break, and you didnt find the gold mine of fuel economy.
Maybe, but I still like to know what the tables do. Even if they aren't being changed or etc.
The pilot injection is a "pre-injection" that is like a tiny little squirt of fuel right before the main injection pulse starts. The purpose is to make the engine run quieter. Don't mess with it.
In a modern turbo diesel, the "timing" is the amount of crankshaft degrees BTDC where the main injection pulse begins. So if you run 50/50 timing, that means that 50% of your main injection pulse happens while the piston is traveling up, and the other 50% as its traveling down. The injectors are mounted where the spark plugs would be in a hemi. The injectors feel the full effect of compression and combustion on each cycle, spraying fuel throughout the ignition process.
You can change the amount of fuel by increasing the pulsewidth, or by simply increasing the values in the base qty table or in the driver demand table. If you change the fueling, then you should also change the boost to match. No sense in blowing black soot and wasting fuel. It should leave a light haze at WOT with the emissions equip removed. Black clouds and lots of smoke is NOT equivalent to more power.
2006 LBZ Duramax
5" Magnaflow turbo-back
EGR blocked
HP Tuned by yours truly
Good info! I agree, about the black smoke. Not sure why some like that.... Fuel is spendy, why waste it by not burning it all the way?
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