LBZ-P2, P3, etc

[killerbee]

Ok, so we have tables for all these injection events. Has anyone seen them work? For instance, the stock tune gives P2 an inj qty of 1.0, but it logs as 0.

Has anyone gotten these to work? ("5" is the number of events, per the stock tune.)

[killerbee]

interesting.

nobody else can use these tables either?

[bballer182]

I have seen the Pilot #2 active. I have not logged the amount in mm3 but i have seen it active using the MAINTSEL_M (in BBL) to see which injection events were active, expecting just the pilot #1 and main and notice pilot #2 had turned it self on some how. So having no use for it at the time i just used B1057 to turn it off as i already had the pilot #2 quantity table set at zero across the board.

[killerbee]

Thanks for the reply.

I think I saw P2 come one once for a second. Might have even logged it. But wondering what these tables can be used for with any predictability.

[bballer182]

Thanks for the reply.

I think I saw P2 come one once for a second. Might have even logged it. But wondering what these tables can be used for with any predictability.

Yeah i dunno about that seeing how there are no available tables the enable or disable the injection events based on any conditions really. I see all sorts of timing tables based on P2 & P3 status but i see nothing that says when they come on or off. It would be interesting to see what one could achieve if anything in terms of mileage tuning with P2 & P3. There isn't even a table that says when P1 comes on other than B1057. The ECM just chooses whatever it wants with no known reason other than B1057.

[JoshH]

I have seen the Pilot #2 active. I have not logged the amount in mm3 but i have seen it active using the MAINTSEL_M (in BBL) to see which injection events were active, expecting just the pilot #1 and main and notice pilot #2 had turned it self on some how. So having no use for it at the time i just used B1057 to turn it off as i already had the pilot #2 quantity table set at zero across the board.


Yeah i dunno about that seeing how there are no available tables the enable or disable the injection events based on any conditions really. I see all sorts of timing tables based on P2 & P3 status but i see nothing that says when they come on or off. It would be interesting to see what one could achieve if anything in terms of mileage tuning with P2 & P3. There isn't even a table that says when P1 comes on other than B1057. The ECM just chooses whatever it wants with no known reason other than B1057.

B1057? Fuel Pressure Max, Fuel Temp? Did they rename the tables, and I have an outdated version?

[bballer182]

Whoops, good catch i meant B1021

[KB3MMX]

Yeah i dunno about that seeing how there are no available tables the enable or disable the injection events based on any conditions really. I see all sorts of timing tables based on P2 & P3 status but i see nothing that says when they come on or off. It would be interesting to see what one could achieve if anything in terms of mileage tuning with P2 & P3. There isn't even a table that says when P1 comes on other than B1057. The ECM just chooses whatever it wants with no known reason other than B1057.

This has been a long standing question of mine as well. There doesn't seem to be a control over turning on the P2 or P3 event unless you just want to kill it by zeroing the tables...but that still leaves the main timing tables while P2 and P3 are being commanded.
Seems like most people will zero out the quantity on P2 and P3 and just cut and paste their table B timing map into their maps in case it is activated by the ecm.

It would be interesting to see how the P2 and or P3 event changes MPG, EGTs, etc

[CwF]

I'll chime in on this old thread for my first post here. I have an anomaly with my tune where I get a small post duration in the 256µs range with a 0-.1 quantity. This has me boggled. I'm not sure what this means, and it was never present in the stock tune. I have the lead in working well and these blank shots only occur on trailing throttle. I've tried to stay in the 350µs range flat across its entire function.

Background is I started on this efilive tune on my personal '06 LBZ with mostly no reference to other Duramax tunes and their forums. I started blank with knowledge from Mercedes,BMW and Nissan studies. As I came across my anomaly and started looking here and other tune forums I found a wrong answer to turn it off and mostly wrong info. From my test the LBZ uses only three shots, never pilot 2 or post 1, so setting 3-5 events are all the same. And without argument, the pilot and post are both huge advancements and turning them off is a step backwards. As far as fuel use goes, neither adds more fuel. Both pre and post events take from the main and the 3 add up to total commanded. The factory tune of the post shot is for temp control and does clean up exhaust. Without a cat or DPF to heat, the amount can be reduced by about half. That other half is simply to raise catalyst temp while the first half raises temp in the late stages within the cylinder and on the way to the turbo thereby reducing particulate formation - read smokeless. The timing changes have purpose also. Factory late timing insures most all that fuel is used for temp rise. Earlier timing can be used for a significant torque increase and faster spool. Factory quantities moved earlier will peak the turbo quickly and it will oscillate the vanes to bleed boost. So back to my half quantity and boost comes on quick without that bleed off. There is a ECT temp inhibit until around 68°C, and then a table to add it back in relative to ECT, however I would expect an associated table to alter timing and it isn't there. Other manufactures will use it on the warm up cycle with earlier timing and higher quantity for a long smooth cylinder pressure and higher warm up boost pressure. It appears redundant here and not used. The Daimler Dodge guys seem to be calling this split injection. OK. Without the timing adjust using post while cold you might as well route the fuel pickup to the oil sump. So we are missing some tables in a useful area that few if any use. On table B9301 I would like to see a little more granularity especially between 1800-2400 rpm and a lower rpm limit, maybe. And with a 60 and 70 mm3 line added I think I could eliminate my little anomaly. Certainly the problem with post tuning is optimization is very load dependent. No post is guaranteed to lower EGT and spool tuning an empty truck would likely waste fuel under a large load if you were to tip into the post range steady state with the turbo already at boost, ie the table would need to shifted up the mm3 range, or at steady state that fuel would be better used earlier in the main shot. At least that's my guess.

So any guesses on a duration with no quantity?

[CwF]

Ok, never mind. I've never looked zoomed in frame by frame. When I do, quantity values often lead and time trails by one frame. And so does the pilot, and so does it show in older logs. Just not as obvious as current logs. I'm chalking this one up to logging technicals, lag, etc. Every time there is a pulse time logged that seemed to have no quantity is actually 0.1. When the post comes in it jumps to >2, just the trailing end of the cycle does it have these micro amounts that register pulse times. With a better cutoff I think they would go away, but with b9301 scaled like it is I can't. I have not found how post helps with anything above 80mm3, but seems to above 50. Anyway...