Instructions for custom tuning the truck with HPTuners.

A bit but nothing I’m terribly concerned with.

 

Ok I wanted to make sure it wasn't the extra adjustments I made..

 

Why do they choose not to lock up 4th at all in the stock tune? I reduced all of my normal lockup RPMs 20% and tow/haul 10% for 5th and 6th. Haven’t touched 4th since I don’t understand why they don’t let it lock at all, and it’s 1:1 ratio. I haven’t actually flashed a file yet with changes to the TC as I’m trying to figure out what to try on the first iteration lol.

 

Not sure but I bet there’s some reason.

My recommendation is do one change at a time and go from there. If you do a whole bunch at once, you’ll never know which one you made that’s causing the issue.

 

Good advice right there

 

Also, is there a chart somewhere that shows output RPM in relation to the vehicle speed so I can get a better understanding of what speeds I’d be at in each gear when I’m setting it to lock and unlock?

 

Yes, check the trans quick reference tool.
https://forum.hptuners.com/showthread.php?86884-Tundra-Tuning-Reference

 

Thanks! I had seen that before before but didn’t have an account so had no access. This pushed me to make one. So if I’m looking at this right, 6th gear ratio is .588. The stock tune file says that TC lockup is applied at 5700rpm and releases at 5400rpm of trans output speed. That means in 6th gear my TC won’t lock up unless the engine speed is at 5700x.588 = 3,350 engine rpm? That seems high, I thought I’ve seen it lock up lower than that. Or, I’m not understanding this properly. I checked for 5th as well and the stock file would mean lockup in 5th would occur at 2,718 engine rpm which also seems high. Somebody learn me!

Edit: nevermind I see what my problem is, that’s only looking at higher throttle positions. It locks up at lower RPM at lower throttle positions.

 

Does anyone have an issue with high idle after a flash(after driving 10 miles or so)? Also it seems like there's a lot of fuel being dumped at startup...
Ok it seems better now, still trying to fine tune throttle and trans shifting I'll post it up when it's done..

 

Can you elaborate on what sort of stuff you have done with trans pressures? (it didn't look like anything changed when I compared this to my stock file...)

 

Anyone else tinker with this? I've lowered mine to get rid of some of that radiator fan roar on cold starts. I haven't notice any deleterious effects so far.
Engine > Idle > RPM > Base Setpoint > Base P/N

 

Ok. I’m on my way down the rabbit hole now, boys. Ordered an MPVI3 and credits today. Should be here sometime next week.

Being N/A, I don’t expect much in the power department, but will see what we can do to wake things up a bit. Then play with the trans a fuzz.

Guess I’ll be ready for when I can’t resist these Magnuson thingies I keep hearing about…

 

I realized today I could track fuel trims vs MAF voltage, where as I had been using rpm which was annoying since I had to scroll around to figure out the rpm vs voltage correlation.





Red means the truck is adding fuel, so you want to scale the MAF values by that % to tell the ecu you're flowing more air and need more fuel. Green means the truck doesn't need as much fuel, and as such the MAF is reading less so scale the values down if green (or negative).

 

Hmmm, gonna have to play with that now that I've started to dial in the 750s

 

Someone in a colder climate, make this change and see if you start getting occasional crank no starts with below 30F ECT. Please, lol.

 

Maybe someone can help me understand the MAF better since I've seen some weird discrepancies.



This table apparently says the g/s flow rate at a specific voltage.

My understanding is the MAF deflects and reads a voltage based on what the MAF is directly experiencing, and the values in the table are essentially a multiplier of the little sliver the MAF sees and then tells the truck the actual total flow through the intake at that point.

But that doesn't seem to be the whole story... The MAF values have a limit of 67.725 (g/s?). My truck, shown above, will not max out the voltage limit but it will hit max cell value earlier than the limit. Why does that happen? I always assumed the MAF values were essentially just used to scale the intake size, in that case the same intake size would always yield the same cell values, but my truck requires much higher cell values than other trucks with the same 4" intake. I have a much smaller pulley on the supercharger, but you would think that would increase the flow, thus increasing the MAF voltage and everything works out. Instead, my truck seems to be reading a higher flow rate at the same MAF voltage as other trucks---meaning the air velocity/flow hitting the MAF is the same, the area of the intake is the same...so why are my cell values so much higher then?

What I assumed was you can get a larger intake, that increases the area, but your overall flow through the intake is the same, so you now multiply the MAF values to tell the truck that it's still flowing the same air even though the MAF itself is seeing slower/less air due to the larger intake. And at some point you get an intake so large that you hit that 67.725 cell value so even though the MAF voltage is nowhere near the maximum, you exceed the multiplier that the MAF allows. But that doesn't seem to be the case, I was just looking at a guy's tune with a 4.5" intake (26% larger than mine) and he makes the same boost as I do, but his MAF values are way lower than mine. If I went to a larger intake I would have even MORE cells maxed out, but this guy is running a larger intake and has lower cell values than mine?

What am I missing? Or is my truck just weird. Other people hit the 5V limit, I hit the 67.725 limit, and the only difference is my supercharger pulley is smaller, the intakes are identical. And I've seen this across a handful of similar trucks and they're all off the same compared to mine.

 

I’ve noticed the same thing as you, after having my MAF rescaled for the 4” intake all of the values are lower across the board than the file for the 3.5”, not the other way around like I was expecting. I guess there’s more than one way to skin a cat when it comes to tuning the MAF.

 

You are referencing grams per second in your post, but your table is in lb/minute. Maybe that is where the confusion is happening? Possibly when you are referencing the other guy's tune, the units are different. Idk if that's the case, just thought I'd point it out.

If you click on the units, you can cycle through them all and the values in the table will change accordingly.

 

I did not know you could click that and it'd change all the units! Thank you sir! Though that doesn't fix explain anything sadly, all the tunes were in lb/min. Though that does explain the 512g/s limit that I've read about, never understood why it said 67!

 

Giggity. Got my initial tune done today. N/A, so no real hope for substantial power gains.

Picked up 7hp for a new high of a whopping 324.7 @ 5,450 RPM which is the same engine speed as the stock max HP.

Torque improvements were better. Picked up 17.3 lbs., but the peak torque rpm is much lower than stock. Peak rpm dropped 850, from 3,800 to 2,950.

Basic transmission work so far, mostly related to accurate tire/gearing input. Removed speed limiter, and bumped rev limiter to 6,300 rpm.

There’s more, but I haven’t dug in to see what the finer differences are. I’ll compare stock to what I have soon and see what all happened. I do know that drivability is different for sure. Much smoother than stock, and just more of it…

 

Reposting here from the supercharger forum:

Injector Constants:

Stock is 0.131663 and that corresponds to about 400cc (even though I think the stock injectors are claimed to be 440cc I had read, but calculating from the constant it comes exactly to 400cc). TRD greens are 535cc and use 0.098381. My 715s use 0.073613.

If you need the injector inverse constant, stock (400cc) is 1.77887, TRD green 535cc is 2.37921, and 750cc is 3.33539.

And for anyone's reference, injector constant is (Old cc)/(New cc) * (Old constant). Injector inverse constant is (New cc)/(Old cc) * (Old inv constant). Injector constant linearly gets smaller as the injector gets larger, and inverse constant linearly gets larger as injector gets larger.

 

Idle Startup Airflow Adder vs. ECT

Engine > Idle > Airflow > Startup Airflow ECT

As near as I've been able to determine, this is the stock table for 2007-2011:



And this is the stock table for 2012 ~ 2018, I haven't personally seen anything more recent:



The X axis is in degrees Fahrenheit and the Y axis in these screenshots are in kPa.
100 = ~ Sea Level
95.3 = ~ 1300ft above Sea Level
86.7 = ~ 4300ft above Sea Level

The values in each cell are in Liters per second (L/s). 1L/s = 1,000g/s.

This is the map that I'm testing:



I've changed my Y axis values from kPa to inHg simply because I know that where I live the Barometric Pressure is 22.2inHg (8,000ft above Sea Level). It's also how I have my Innovate Boost/AFR gauge set.

As most are aware, I've been going on a bit about my long cranking times and initial black smoke coming from the tail pipe when it eventually fires, after changing from the TRD 535cc fuel injectors to the Five0 750cc fuel injectors. Other miscellaneous related component are: TRD/Mag blower and intake, +2psi URD 2.35in pulley, and Walbro 450 fuel pump. When I've been starting my truck with the stock airflow adder map, it has required anywhere from 2-4 cranking cycles before it starts, and it puffs black smoke from the tail pipe no matter if it's a cold start or if it's been run and sat briefly or for a while.

There were some recommendations that I have a look at and adjust some of the values in the airflow adder map. Being kinda stubborn, I insisted to myself that it was a fuel issue, because I just changed the injectors...right? I messed about trying to figure out how to lessen the amount of fuel during cranking. Well, it appears that was a dead end so I came back to the airflow adder map.

I initially spent a bunch of time searching and reading trying to find more information about how to go about determining values to input and try, at least to get started. That seemed to be a dead end as well.

I started really looking at the differences in the values of the stock maps in the 25.6inHg row. Realizing that if this didn't seem to be a need to reduce the amount of fuel during cranking, maybe I should have been looking at more air, as suggested. In the map, I was focusing on the vast difference between the values in that first row when I noticed that in the bottom right hand corner, HPT showed that these values had a range of 0 to 20L/s.

I said fuck it and changed the entire top row to 10 (HPT rounds these values, that's why they're not whole numbers) and gave it a crank and it started on the first attempt and there was almost no discernable black smoke but still a little hesitation. I bounced the values up to 11 with even better starting and no black smoke. Super stoked at this point. I left it at that for the time being wanting to see what it was going to do the next morning.

I went out this morning when it was 20°F. It started on the first try but struggled just a little bit and I didn't notice any black smoke. I let it run long enough for the ECT to reach 50°F, shut it off, bumped the 14°F value (closest to 20°F) up to where it is now and flashed. I then started the engine again (ECT at 50°F) and it was better with less hesitation so I increased the value, but not as much then flashed again. I repeated this for the 86°F and 158°F column as well. I didn't do 185°F not wanting to wait, and the 158°F start seemed pretty good.

These values are preliminary and pretty course. But I found this to be mildly exciting and wanted to get my experience out there for others with this issue to experiment with. I'll tinker with the other rows when I'm at those elevations.

@snivilous
@ZPhilip

 

I wonder if decreasing these values for the people with starting issues (and no black smoke) could help? They seem to not be injecting enough fuel, so by reducing the airflow that might help target a better startup AFR? I still think it's a fuel pressure/priming issue for most people, but might be worth a shot. Truck might be adding too much air since there's hardly any fuel initially, essentially the exact opposite you experienced.

 

A majority of the values seem pretty small to begin with, to me. How low can it go? I did read from one tuner that they try to target a cold startup AFR of 13.5, I have no idea what engine they may have been referencing. By the time my wideband warms up it's indicating ~10AFR in OL but decays to CL within about 90 seconds. I don't know what stock behavior is. I'd guess that many try to attain stock-like startup characteristics. I'll have to monitor to see if this changes with my recent map changes. *Mental note*. It sounds like what you're suggesting could be a workaround, or verification for troubleshooting. But I'd guess that many would suggest that the "real" issue of pressure bleed should be addressed. That may hinge on whether the vehicle is their daily driver or a hobby/secondary use vehicle and wouldn't be bothered if it took a little bit more to start up. To me it was embarrassing to be at the filling station, yit-tit-tit-tit-tit-tit-tit-tit......yit-tit-tit-tit-tit....blub-blub-blub and have a cloud of black smoke come from the tail pipe, not to mention the already mentioned wear on the starter/possible fuel washing. Call me paranoid.

 

A couple random things that occurred to me about cold start AFR target. We'd want something that would allow us to reach in through an open window, hit the key and it'd fire. Another would be a remote start setup, hit the remote button while you're out of sight/hearing and being confident that it has started/is running. The target ratio would need to be something that the stock narrowband sensor could read (in a stock vehicle). I wonder if this hypothetical target could be reached merely by tweaking the above airflow adder table....

I guess I know what I'm going to try next....

 

Fine work @Wynnded it appears perseverance pays off.

 

Interesting. Those values are WAY higher than I was experimenting with. Have you hooked your wideband to a constant 12v to get a reading when cranking?

 

I've considered that, but ran out of weekend. Maybe next.

So, as it turns out, this doesn't seem to be solving the issue. I wandered out and started the truck about four hours after my first test and it needed two tries to get it to start and there was still smoke. I messed around with it a bunch more and finally realized that a post on HPTuner's forum might yield some suggestions. I don't think the neighbors really appreciated the smell either.

 

What about just increasing the startup time to like 5s?

 

I interpreted that as what determines what the GM folk call "startup flare". When the engine first starts, it revs 200 rpms above the values in the Target Idle Speed P/N table for the time duration shown in the Startup Time field (3sec). I changed my TIS (P/N) table and posted about it last month. I've returned them to stock since having hard starts to eliminate that as a factor. I don't think I've ever changed Startup Time & Adder as I think that only comes into effect after the engine actually fires. I've been trying to think only about the narrow timeframe of actual engine cranking. Maybe some of these things overlap more than I'm taking into consideration.