Because of the retarded injection timing, plain and simple. Its an emissions thing.

 

Well, there is not much to misuderstand there.

Again, it leads to all the info compiled to date and Marco's own statments. So removing what he mislabeled the 3rd event early on causing the ECU to "freak" wouldn't be considered a 3rd event? Splitting the main event into 2 wouldn't be considered a 3rd event? I can see why power would drop and EGT's go high when thta event was dropped as the ECU has a rudimentary compensation algorithm that will try to adjust based on read parameters. I would think that would indicate rather than negate the presence of the event. Same with splitting the main event into 2 would indicate a 3rd event. Sematics maybe?

As for warming the CAT, I cannot 100% verify the composition of the CAT without a metallurgical test, but all the descriptions indicate it is designed to be a soot trap and catalyst not an NOX converter which would require heat. It is definitely not the same as the gasser CAT's and the soot particulates were the bigger concern at that time. The NOX emissions were handled with the EGR solution and timing.

I have seen a demo of engine diagnostics equipment that purported to be tracking the injection events on an 600 series engine. It showed what was descirbed as the three injection events and showed the wave form changes as the rpm's were raised. The 3rd event was minimal until you hit the higher rpm's then it showed a wave form change. This tracks almost exactly with what I observe with drive pressure as related to load and rpm, a jump in the higher r's that indicates added fuel to activate the EGR and create the TQ/HP dyno charts. The thing is I have run a gen1 and a gen3 on a dyno at roughly the same HP and showing completely different TQ curves. Something is making that TQ curve flat from 1700-2900 rpm's on a 3rd gen that doesn't show on a 12V. It fits with 3 injection events staggered across the combustion event. Others have reported seeing the same oscilliscope evidence, and Don M had a description of how the 3rd event is used to meet both power and emissions given the cam profile.

I think the higher EGT's at low coolant temp is more the ECU saving the engine rather than trying to warm itself. Retarding the injection timing on a cold engine is going to reduce cylinder pressures, reduce emissions from unburned fuel, keep unburned fuel from fouling the oil, and increase EGT's a bit. You don't really want to throw higher cylinder pressures and more heat into the combustion event on a cold engine. It will stress block, pistons, rings, etc, more so minute adjustments are made to minimize the stress.

Cam profile and timing simply cannot account for the differences in drive pressure curves between a CR and jerk pump engine. Late or over fueling is the only way you see those kinds of spikes in DP. Keep in mind an HE351 mimics very closely the profile of a modified HX35/12 when run on the same single event engine. For this mimicry to happen it has to be the addition of late fueling to drive it. Lobe seperation and valve timing overlap cannot generate heat and pressure to that degree.

You heard what you heard from Marco, I believe that. Now, take what I have laid out and balance it against what you heard and give me a totally disspassionate unbiased conclusion based on the observed phenomena. Am I off track?

It may very well come down to a truth somewhere in the middle of all the conclusions. Knee jerk reaction is Marco was "having you on" , but, I have seen his posts over the years and he frequently will throw something out there that is waaayyyy off what he really meant. I have to believe there is way more hear than a black or white answer.

 

I am not sure on the Cat either.. I do know that diesel cats in general are not like Car ones, but thats about it.. I know mine works well as it sits in the attic

As for the Tq curves being flat I do know that is not from the 3rd event, that is from being electronically controlled. The VP44 was the first the have a flat tq curve. IMAGE.. The electronics are able to keep hp rising from peak tq to peak rpm, where on a mechanical engine hp is the same from peak tq thru redline, hence the dropoff in tq.

I don't disagree with your reasoning.. I have good reason to believe it, as well as believe Marco. There appears to be lots of conclusions, I had someone telling me a few weeks ago they knew the 3rd event to only happen at low rpms because there was no time for 3 firings at high rpms... So who really know.

This summer I may play with my truck while towing and see what happens in the upper rpms on my DP/EGT/Boost gauges... I usually don't see over 2400 while towing, so all my 2400+ stuff is empty.

What we really need is EFI Life for the Cummins... then we would know.