I, still, have to try out the current toon, but I have been pouring over posts related to FUEL PRESSURE, IPW, and all the stuff I believe is related to what I'm trying to test. Something (maybe unrelated or not important) just hit me, as (if I
ASSume injecting before TDC
doesn't matter - again - still researching and NOT saying it doesn't - just making an assumption to move my point forward) I'm really having the biggest trouble when I "PEDAL" the THROTTLE. It seems, for now, at 24MPa RAIL PRESSURE DESIRED, that at a WOT hit from about 2000 RPMs (4th GEAR ~ 35 MPH), RAIL PRESSURE holds right at 24MPa, and
just seems to start to trail-off at redline (6500 - plus-23MPa). IPWs are holding the entire hit at about 4.8ms, so that seems okay, too. I'm guessing I could stand to bring DESIRED RAIL PRESSURE back down, toward 20MPa (OEM pressure), and might try 21MPa this time. But - everything is looking "OK" at WOT, and
NOT "PEDALING"... Which leaves contending with the "PEDALING"-part...
I pulled some fueling from the middle of the E92 MAF curve (~5500-8000Hz), because I was running a little fat anyways, and then took a little more, just to relieve the strain on the DI. I have the E92 MAF blending back into full fueling around 3/4 of the top end (~9000Hz and up). I'm hoping this might be enough to aid in reducing the load on the DI when it tries to recover and building RAIL PRESSURE back up enough to control IPW. But - I realized something else that MIGHT be contributing to why I've been experiencing these pressure undulations...
I haven't been playing with the DESIRE RAIL PRESSURE [17071] table since installing the upper. Until the upper, I had gotten it pretty close to where my STFT/LTFT-corrections were not much more than around 10% RICH. The MAF range these corrections had been made was in around the middle of the E92 MAF CURVE, and with reducing it the way I am now, this might help those CLOSED LOOP (CL) CORRECTIONS reduce further. With the corrections getting closer to ZERO, I might be able to bring [17071] pressures back up, in those CL areas. That's relevant because I'm now postulating me dropping FUEL PRESSURE in [17071] to correct for CL in these areas might be causing some of the RAIL PRESSURE fluctuations. By not commanding enough in [17071], after "PEDALING", I'm falling into part of the this DESIRED FUEL model that is commanding lower PRESSURE that is too low to recover fast enough for fueling demand, resulting in IPWs that can't come under control for the rest of the hit. I can see what seem like large swings in COMMANDED RAIL PRESSURE (that I made earlier) and think it drops too low, and that could be part of why PRESSURE just doesn't have time to recover enough. I'm thinking I need to add this to part of my last test toon...
In summary of this latest plan: I reduced the E92 MAF CURVE in the middle; I brought DESIRED RAIL PRESSURE back up (to, basically) OEM levels (in [17071]); and MIGHT take a little SOI out of the ALCOHOL table, in the same area in hopes that might take care of this "last" issue. Adding those changes together seems to, theoretically, give me a little more headroom for DI. Less MAF will be offset, some, with lower RAIL PRESSURE, but I was running a little conservative anyways, so that might be a wash, and allow me to get closer to 5.1-5.1ms for a cold day. Unless someone confirms (either way) otherwise, I still have to do more research (I've spent tens of hours over the last few years on this, but with a stock cam [and running gasoline], there wasn't much of a point, lol...) on the below bullet points. I know I'm making, at least, a couple of assumptions in my theory for this toon, but maybe some of what I need to look more at doesn't matter too much...
- Research safe limit of LT4 INJECTOR PRESSURE
- Research INJECTION STARTING BEFORE REACHING TDC