Fuel Flow Rate PIDs

[sneaky98gt]

It's taken me a couple of years, but I'm finally getting around to doing some of my own tuning on my LB7 (2003). I've got EFI Live / a V2 Flashscan. But before I started changing anything, I thought I'd first spend some time datalogging and getting my head around what's actually going on (versus just blindly changing some numbers).

Most everything has made sense so far, but there is one thing that has me puzzled and I haven't found a good answer searching just yet. What PID should I be logging for the fuel flow rate? Say, for example, to use to create a map of the Main Injection Pulse (B0720) table? I'm currently logging Throttle Base Fuel Flow Rate, Main Injection Fuel Flow Rate, and Main Injection Fuel Flow Rate 2. I found an old post stating the Main Injection Fuel Flow Rate PID has a bug that won't allow it to log over 80 mm3, and my logs show that to be true, so that one is axed. But what about the other two?

Is Throttle Base Fuel Rate what's being commanded via the TBIQ table, while Main Injection Fuel Flow Rate 2 is the actual fuel rate after being potentially limited by ECT, MAF, or TLIQ tables? Is that how it works?

Thanks in advance!

 

[Chevy1925]

Sounds about right. the main injection fuel flow rate 2 is the pid you monitor to make sure you are getting the mm3 you want for fueling in the main injection pulse table. you may be converting back and forth between mPa and psi alot too as we generally talk about rail pressure in psi but its mainly mapped in EFI Live as mPa

 

[THEFERMANATOR]

Your TBIQ table is just that, how much fuel you're requesting via the accelerator pedal. You have to keep in mind that is only a requested amount, the actual amount will be limited by the limiters such as max fuel at each pressure, max fuel to be injected table, your maf limiting table, and your torque limiting tables. Be VERY VERY careful changing any of the torque based fueling/limiter tables as they all control defuel on shifts. I would recommend you start by setting your TBIQ table do it can request 100mm3 of fuel (no need to go higher as lb7 tables max out at 100mm3), then going through your limiters so they will allow 100mm3, and finally go to your torque limiter tables so that they will allow 100mm3 of fuel. There is a good bit of power to be unlocked just by getting it to go to 100mm3 of fuel as stock maxxes out around 89mm3 of fuel. Then go in and use the timing calculator and clean them up. Keep in mind at lower power levels(under 40mm3 of fuel), the stock tables run well in excess if 100% btdc on the timing, but you can safely do this at lower power outputs, but when you start getting into the power, be conservative.

 

[sneaky98gt]

Sounds about right. the main injection fuel flow rate 2 is the pid you monitor to make sure you are getting the mm3 you want for fueling in the main injection pulse table. you may be converting back and forth between mPa and psi alot too as we generally talk about rail pressure in psi but its mainly mapped in EFI Live as mPa

I appreciate the help! Yes, I've already noticed that there's tons of units options available when charting and mapping the PIDs, which is different from previous tuning experience I have where you're stuck with what you've got. Thankfully EFI Live has made it pretty easy to change it around.

Your TBIQ table is just that, how much fuel you're requesting via the accelerator pedal. You have to keep in mind that is only a requested amount, the actual amount will be limited by the limiters such as max fuel at each pressure, max fuel to be injected table, your maf limiting table, and your torque limiting tables. Be VERY VERY careful changing any of the torque based fueling/limiter tables as they all control defuel on shifts. I would recommend you start by setting your TBIQ table do it can request 100mm3 of fuel (no need to go higher as lb7 tables max out at 100mm3), then going through your limiters so they will allow 100mm3, and finally go to your torque limiter tables so that they will allow 100mm3 of fuel. There is a good bit of power to be unlocked just by getting it to go to 100mm3 of fuel as stock maxxes out around 89mm3 of fuel. Then go in and use the timing calculator and clean them up. Keep in mind at lower power levels(under 40mm3 of fuel), the stock tables run well in excess if 100% btdc on the timing, but you can safely do this at lower power outputs, but when you start getting into the power, be conservative.

I appreciate the help now, and let me say: I REALLY appreciate all the help you've given over the years on various forums. During my searching the last few weeks regarding tuning these trucks, I've found tons of very insightful posts from you over the last 10-12+ years. They've been extremely helpful, and they're much appreciated.

My early intentions are to continue logging and learning the software, keep researching and reading, and continue building and tweaking my own equations and spreadsheets. I'm unashamedly logging my (paid for) DSP5 tunes to glean as much info as I can regarding how they work and at what values. Same for evaluating some of the older highly-regarded tunes (yours and Dave's for sure) in the library here. Also checking out the ones that everyone has roasted over the years, just to see what NOT to do. LoL.

The torque settings are not something I intend to touch early on. I've read just enough to know that I don't know enough. Haha. That said, I did find a thread or two (and an Excel calculator) from a member here (I think 2004LB7, or something to that nature) regarding parsing down the torque tables and comparing them / updating them relative to the TBIQ table (I think). It sounded like something that made decent sense, but that's definitely a 'later on' type of item.