The tuner doesn't read the ECU, you click 'read vehicle' and hpt sends you a stock file.Quote:
Originally Posted by mr.joker
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The tuner doesn't read the ECU, you click 'read vehicle' and hpt sends you a stock file.Quote:
Originally Posted by mr.joker
I was curious to know if anyone has encountered long cranking times after upgrading to 750cc injectors (from the TRDs), not only just long cranks, but needing multiple attempts before the vehicle starts. When it finally starts, there's a plume of rich black smoke from the tailpipe. I have the correct injector constant and offsets. The LTFTs are +/-3%. This TRD S/C'd 2011 has a Walbro 450 fuel pump and the stock fuel pressure regulator, not boost referenced. It transitions to Closed Loop in about 90 seconds. It runs fabulous in every other respect. All that I changed were the injectors, the inj. constant/offsets and adjusted the fuel trims. The only unusual aspect is my elevation of 8000ft. I thought that I was getting somewhere by bumping up the Startup Airflow tables, but as it turns out that really doesn't solve it. Thanks for any feedback/ideas.
You mention the issue of hard cranking when using large injectors. I maxed out my TRD 535cc injectors so I installed some 750cc ones. I updated HPTuners with the relevant data relating to them, but now have a pretty consistent hard starting issue. I was wondering if you would be willing to share some guidance as to how this might be dealt with. Any time you can spare to this is greatly appreciated.Quote:
Originally Posted by QTR FMS
Quote:
Originally Posted by Wynnded
Im in the same boat here. Extended cranking after newly installed Deatschwerks 650cc on my supercharged Tundra. Any help from the much-smarter-than-me members here would be greatly appreciated!
2008 Land Cruiser (stock)
Looking for Harrop Stage 1 and Stage 2 tune
@SlowNStock, @JustDSM, et al.
I've uploaded my tune and these logs in an effort to try to solve my warm/hot starting conundrum. One log is a cold (overnight) start. One is an immediate hot restart. The two remaining are warm/hot restarts.
TRD blower
750cc injectors
Walbro 450lph pump
Black soot from tailpipe on warm/hot restarts, not on cold (overnight) starts.
Just prior to the 750 injectors, I had the TRD green injectors and zero starting issues, with the same pump. Fuel pressure has been checked out at a rock steady 50psi. Truck runs great otherwise...
Thoughts, feedback and questions craved. Thanks for your time.
Attachment 132850
Attachment 132851
Attachment 132852
Attachment 132853
Attachment 132854
The problem generally stems from cranking injector pulsewidth, exasperated by a few factors (altitude, higher fuel pressure, etc.). Unfortunately, that isn't defined in the calibration for your truck (it would be under Engine -> Fuel -> General -> Cranking Fuel). Here's what that table looks like for a non-SC truck, for reference:Quote:
Originally Posted by Wynnded
Attachment 132857
As a bandaid, we can come in and add to the base startup airflow table (Engine -> Idle -> Airflow -> Startup -> Startup Airflow ECT) to bring in some more air and offset the excess cranking fuel. Startup Airflow IAT can be worked as well, as the greater of the ECT and IAT tables will determine the cranking target.
You'd referenced trying Startup Airflow with mixed success - what values and which table(s) were you using?
Other feedback
From your logs, you're getting quite a few Cylinder 7 misfires - have you done any troubleshooting to see what's going on there?
While you didn't ask for it, just a word of caution: you have component protection disabled, but haven't added fuel in PE.
Thank you for your time and insight, I really appreciate it.
I have seen this table in other calibrations, usually in 2018 and newer versions, but never for what appears to be a FFV version like in the screenshot. I have wished that it was available in my calibration as it seems to me that's where the issue would be best improved.Quote:
Originally Posted by SlowNStock
Yes, I have dabbled with both Startup Airflow ECT and IAT tables focusing on the columns where temperatures are above 100?F as this is where the starting difficulty resides. This is one of the first things that I tried. I began with adding small amounts to the stock values, then I increased them in greater increments. I can't recall at present how high I went with the values (utilizing both tables) as it was some time ago, but it could be that I blew right past a workable value or got frustrated when the initial attempts were nonproductive. I will go back again with a more systematic methodology. I see that the values have a possible range from 0 to 20 L/s, I'll break that down and respond with feedback/results. Maybe I wasn't diligent enough with that trial and I've been chasing around in the wrong areas of the tune.Quote:
Originally Posted by SlowNStock
The posted version of the calibration is my Base version that I make individual alterations to so that I don't get too many changes mixed up and lose track of them. The misfires were from an experimental variation that I abandon upon getting them. The same applies to PE/component protection as I'm trying to keep my focus on the starting aspect; I'm not that far into my tune yet. Your assessment was more thorough than I was expecting, many thanks for that. I should have feedback some time tomorrow.Quote:
Originally Posted by SlowNStock
Additional: For reference, I see in the Airflow ECT table that the lowest value for Barometric Pressure is 86.7 kPa. Where I live it's 75.3 kPa. Would there be any benefit to scaling that axis to reflect that?
The "easy" way to work Startup Airflow ECT is to take an airflow value from a temperature you know works - say 50F - then carry that forward into higher temps at the same baro. Knowing that we shouldn't need more air than that at higher ECT, you can then simply iterate downwards (say, 10-20% at a time) for the higher temps until you get a satisfactory start - too much airflow and it will struggle to start, a little high and it will have some excessive startup flare.Quote:
Originally Posted by Wynnded
Startup Airflow IAT is a little trickier, and sorta requires a reasonable Startup Airflow ECT to be tuned well, so better to save that for later, if it ultimately needs much attention at all.
Yes, you can try scaling the axis some to get more range in the table, since you'll regularly see low baro.
Here's an example revision, showing how that the ECT table may look with a scaled axis and increased airflow at low baro (this is just notional, so you'll have to make adjustments): Attachment 132894
This file uses a later TRD startup airflow table as the base, with some of the drop in the 14F - 50F range smoothed, the 50F airflow carried forward at 75 kPa, and the 87.5 kPa set roughly in between. Keep in mind your current base has the older TRD startup table, which has a big shot of airflow (>7 L/s) at 50F - 86F and 86.7 kPa, so if you have startup issues with the attached file, you may try something similar to your current file. The basic idea for the ECT table remains the same, though: find a startup temperature that works well, carry that airflow value forward to higher temps, then iterate the airflow value downwards.
I had a little time to earlier to try some of what you just suggested, of sorts. I looked at the value in the 50?F/86.7kPa cell (a temperature where the vehicle starts perfectly, in essence, a cold start) and somewhat arbitrarily input 5 L/s. I am certain that this is a value quite a bit greater than what I tried in previous experiments. As you mentioned, this may be a little bit too high as there is a startup flare. The thrilling thing is that there isn't the sooty puff at the tailpipe. Excited to finally be on the right path! Tomorrow I'll experiment with incrementally reducing that to minimize the flare.Quote:
Originally Posted by SlowNStock
I have noticed that 2008-2011 and 2012+ have different Airflow ECT table values and will be altering the one originally associated with my calibration, that's what prompted me to start with such a large value. I will also rescale the barometric pressure axis. If tuning the Airflow ECT table if found to be too coarse, maybe that would be an indication to have a go at the Airflow IAT table for a finer adjustment.
This is great, when I get this sorted I can look at PE and Component Protection which I know you've discussed with Snivilous and written about in great detail. ZPhilip, he and I have been scratching our heads on this starting issue to no avail and I know this will make them happy as well. I'll report on how this goes tomorrow.
Thanks again!
For the IAT table, the basic procedure is:Quote:
Originally Posted by Wynnded
1) Drive until the ECT reaches operating temp, then shut it off immediately after stopping (to keep IAT low).
2) Restart the truck and note any issues (flare, excessive cranking). Add/remove to address long crank/flare if IAT airflow is greater than ECT, otherwise make the corrections to the ECT table.
3) Let the truck idle until maximum IAT is reached, and shut it off.
4) Repeat (2); restart the truck, note any issues (flare, excessive cranking), and adjust the appropriate IAT cell as needed.
Getting the ECT table working well should be done first, just be mindful of where the IAT table may command more airflow. You can zero out the IAT table while working on the ECT to prevent it from affecting startups, then use a similar approach to start tuning the IAT table (start with a high value, and decrease until excessive flare disappears) once the ECT table is done.
Keep us posted on any questions, issues, or successes you have.
Your timing is impeccable, I just returned from trying out some basic Airflow ECT values and a drive. While doing so, I was trying to imagine a scenario where IATs might ever be greater than ECTs. I was unable to. ECT operating temps are in the neighborhood of 185+ degrees, and I've never seen an IAT of greater than 130?F and that was after shutting off the engine and heat soaking the engine compartment. In such a case, when restarting the engine, the AITs drop 15-20 degrees. Even after letting the engine sit for a couple of hours, I can't say that I've noticed IATs > ECTs. Maybe this is just a regional phenomenon with the really thin air. Maybe this will lessen the time necessary for this procedure, possibly even eliminating it. I suppose time will tell. I tend to get ahead of myself.Quote:
Originally Posted by SlowNStock
Are you familiar with what stored information HPT is "erasing" when it flashes as it relates to this? I noticed that after a flash (tweaking LTFTs, no Airflow ECT change) when I restarted, there was a puff of black from the tailpipe even with the higher values in the Airflow ECT cells from last evening. I'm wondering if I should discount those observations and only take into account warm/hot starts when there have been no changes as that's more in line with a typical restart scenario.
Speaking of getting ahead of myself, it's tricky for me to not consider what might be recommended if I happen to reach values in the 86?F ECT and greater columns that are equal to the presently greatest value in the table, in this case, the 50?F column. I'd be inclined to go with even greater values until I experience startup flare/lean hard start but thought I should inquire as a safety measure. There's still a lot of airflow to go up to as suggested by the 0-20L/s range indicated in the software for that table. Thoughts....
Meanwhile, so far every starting event has been brief and successful on the first attempt. This is a great improvement!
To clarify, the IAT table value is referenced if the airflow value is greater than in the ECT table, not the temperature.Quote:
Originally Posted by Wynnded
Referencing the base values per your earlier file:
Attachment 132933
If we had a startup where IAT was at 120F and ECT was at 185F, the IAT airflow would be 1.25 L/s (via linear interpolation) and the ECT airflow would be 0.0781 L/s, so the greater airflow value of the two (IAT) would be referenced and startup airflow would be 1.25 L/s, even though the IAT temp is less than ECT.
In practice, this means that, for the base calibration, cold starts are dominated by the ECT table (ECT airflow is greater than IAT airflow for the majority of cases where ECT temp = IAT temp), hot starts by the IAT (minimum IAT airflow is greater than ECT airflow for ECT of 158F+), and warm starts can be either one (because of the interpolation in airflow values between ECT of 86F and 158F relative to the floor of 0.47 in the IAT table).
The first start and drive after a flash can be a bit funny, particularly if it's warm, so it's usually something you can disregard. Just keep an eye on it for subsequent starts not immediately after writing and address as needed.Quote:
Are you familiar with what stored information HPT is "erasing" when it flashes as it relates to this? I noticed that after a flash (tweaking LTFTs, no Airflow ECT change) when I restarted, there was a puff of black from the tailpipe even with the higher values in the Airflow ECT cells from last evening. I'm wondering if I should discount those observations and only take into account warm/hot starts when there have been no changes as that's more in line with a typical restart scenario.
Other than the issues you mentioned (hard start, excessive flare), not really any risk. Just be sure to make reasonable increments and keep testing so you don't accidentally step far outside of a useful value.Quote:
Speaking of getting ahead of myself, it's tricky for me to not consider what might be recommended if I happen to reach values in the 86?F ECT and greater columns that are equal to the presently greatest value in the table, in this case, the 50?F column. I'd be inclined to go with even greater values until I experience startup flare/lean hard start but thought I should inquire as a safety measure. There's still a lot of airflow to go up to as suggested by the 0-20L/s range indicated in the software for that table. Thoughts....
Meanwhile, so far every starting event has been brief and successful on the first attempt. This is a great improvement!
Copy, thanks for the clarification. ECU looks at ECT and IAT tables and utilizes the greater airflow value and applies it for startup.Quote:
Originally Posted by SlowNStock
Understood.Quote:
The first start and drive after a flash can be a bit funny, particularly if it's warm, so it's usually something you can disregard. Just keep an eye on it for subsequent starts not immediately after writing and address as needed.
10L/s appears to fit that bill. Hard warm start and misfires. Boundaries :cool:Quote:
Other than the issues you mentioned (hard start, excessive flare), not really any risk. Just be sure to make reasonable increments and keep testing so you don't accidentally step far outside of a useful value.
This morning I went out and trialed values for Startup Airflow ECT at the listed temperatures in the table. I zeroed out the IAT table to avoid confusion. In the attached tune are what seemed to work for no startup flare and minimal sooty puff from the tailpipe upon post-flash restart.Quote:
Originally Posted by SlowNStock
Here's the bugger; when I return to the vehicle later in the day, say after 90 minutes pass, two attempts are required to get it to start again and there's notable soot upon firing. That log is included.
Attachment 132977
Attachment 132978
Quick thoughts from the log and cal:Quote:
Originally Posted by Wynnded
1) You'll want to blend the ECT airflow across baro, otherwise small changes in baro above 75 kPa result in fairly significant changes in airflow.
2) The MAF transfer function has been changed quite a bit with some irregularities - are you running the TRD/Magnuson intake?
3) We're still seeing quite a few Cyl 7 misfires after startup, so it would be worth checking the plug, and swapping the coil and injector each to a different cylinder to see if the misfire follows.
Overall, the logged startup being more challenging without a tuned IAT airflow table isn't entirely untoward, as it has a warm ECT, but fairly high IAT.
Got it. I went into it thinking that it would be better to change as few cells as possible.Quote:
Originally Posted by SlowNStock
I don't know what MAF transfer function is. I have a Hewitt SAIS bypass kit installed that makes some changes to the signal to the ECU from the ECT and IAT sensors. I've had it connected and disconnected at various times and I don't notice that it makes any difference relating to the starting issue that I'm experiencing other than that the SAIS pumps don't run when it's connected and they do when it isn't according to however Toyota has the system set to run. I disconnected it this morning before experimenting and will leave it so for the duration of this process.Quote:
2) The MAF transfer function has been changed quite a bit with some irregularities - are you running the TRD/Magnuson intake?
Yes, the intake I have installed is the TRD/Magnuson system that it came with originally; the air filter is an AFE dry filter element. There are no modifications to the airbox.
Ya wow, hadn't been looking at that. I went back and looked at logs that I made while making adjustments and they were happening then as well. Something else that I noticed on logs where I made changes, flashed and started the engine, there were more misfires on that first post-flash restart and far fewer to none on subsequent restarts. I moved the Cyl 7 plug to Cyl 6 (logs indicated no misfires for that cylinder) and the coil to Cyl 4.Quote:
3) We're still seeing quite a few Cyl 7 misfires after startup, so it would be worth checking the plug, and swapping the coil and injector each to a different cylinder to see if the misfire follows.
Overall, the logged startup being more challenging without a tuned IAT airflow table isn't entirely untoward, as it has a warm ECT, but fairly high IAT.
I watched misfires more closely today. On cold start (50F) there were 3 misfires, Cyl 2 had 1, and Cyl 4 had 2. On 95F start there were misfires for Cyls 1,3,4, and 5. I don't know if this is typical or not. As the engine warmed, the misfires became less in number and frequency. They never seemed to be dominated by one specific cylinder, they were just all over the place. The only exception that I might note was that after everything was warmed up and on the first start after a flash, Cyl 1 had the most misfires (up to 13) with infrequent others in random cylinders. As things settled, they decreased to zero. Subsequent restarts without a flash had minimal or zero misfires, as the engine continued to run, there were zero additional misfires. I logged while on an errand and there are now pending codes for P0300, P0301, and P0307. I hadn't realized this was occurring.
Tomorrow I think I'm going to try the example ECT table that you posted and see if I can make any progress.
Quote:
Originally Posted by Wynnded
Usually a good approach to limit the changes, but have to also be careful about making an "island" where there's a large difference from adjacent cells. Don't have to be overly scientific about it, just smoothing vertically between 75 and 100 kPa a couple times will get it in the ballpark.
My mistake, should have been clearer - that's the Engine -> Airflow -> General -> MAF Calibration -> Airflow vs. Voltage table. "Transfer function" is the generic name for these tables - it's any function (in this case, a lookup table) that converts (transfers) an input (sensor voltage) to an output (mass airflow).Quote:
I don't know what MAF transfer function is. I have a Hewitt SAIS bypass kit installed that makes some changes to the signal to the ECU from the ECT and IAT sensors. I've had it connected and disconnected at various times and I don't notice that it makes any difference relating to the starting issue that I'm experiencing other than that the SAIS pumps don't run when it's connected and they do when it isn't according to however Toyota has the system set to run. I disconnected it this morning before experimenting and will leave it so for the duration of this process.
Yes, the intake I have installed is the TRD/Magnuson system that it came with originally; the air filter is an AFE dry filter element. There are no modifications to the airbox.
Since you are running the TRD/Magnuson airbox unmodified, your transfer function should be unchanged, and any changes should result in a smooth, approximately polynomial function - the only real exception being due to intake design issues (MAF too close to a transition, bend, TB, etc.). The table in your most recent file has some fairly significant changes in a few places and some irregularity overall.
Misfires immediately after startup and writing are pretty common and nothing to worry much about, but the regular misfires on 7 jumped out as a possible injector leak given your starting issue.Quote:
Ya wow, hadn't been looking at that. I went back and looked at logs that I made while making adjustments and they were happening then as well. Something else that I noticed on logs where I made changes, flashed and started the engine, there were more misfires on that first post-flash restart and far fewer to none on subsequent restarts. I moved the Cyl 7 plug to Cyl 6 (logs indicated no misfires for that cylinder) and the coil to Cyl 4.
I watched misfires more closely today. On cold start (50F) there were 3 misfires, Cyl 2 had 1, and Cyl 4 had 2. On 95F start there were misfires for Cyls 1,3,4, and 5. I don't know if this is typical or not. As the engine warmed, the misfires became less in number and frequency. They never seemed to be dominated by one specific cylinder, they were just all over the place. The only exception that I might note was that after everything was warmed up and on the first start after a flash, Cyl 1 had the most misfires (up to 13) with infrequent others in random cylinders. As things settled, they decreased to zero. Subsequent restarts without a flash had minimal or zero misfires, as the engine continued to run, there were zero additional misfires. I logged while on an errand and there are now pending codes for P0300, P0301, and P0307. I hadn't realized this was occurring.
You may need to increase the values based on your recent testing, just be sure to blend that increase per the above.Quote:
Tomorrow I think I'm going to try the example ECT table that you posted and see if I can make any progress.
Speaking of "island", how about that one in the 50-86F cells of the 2007-2011 models. The newer Startup Airflow ECT table didn't work out, so I reverted to the older one and hopefully made some improvements.Quote:
Originally Posted by SlowNStock
I think that I've made some improvements to this table in terms of smoothness. This would bring us to the matter of Fuel Trims though. That table was a result of trying to get LTFTs that were near zero. Is that not the goal that it seems to be made out to be? I've never seen fuel trims from a stock engine, so I don't know what kind of percentage swings are typical. How much correction is normally left to the ECU? I know that it has limitations. I understood that the intent was to minimize that swing.Quote:
My mistake, should have been clearer - that's the Engine -> Airflow -> General -> MAF Calibration -> Airflow vs. Voltage table. "Transfer function" is the generic name for these tables - it's any function (in this case, a lookup table) that converts (transfers) an input (sensor voltage) to an output (mass airflow).
Since you are running the TRD/Magnuson airbox unmodified, your transfer function should be unchanged, and any changes should result in a smooth, approximately polynomial function - the only real exception being due to intake design issues (MAF too close to a transition, bend, TB, etc.). The table in your most recent file has some fairly significant changes in a few places and some irregularity overall.
I'm beginning to recognize this pattern after startup and writing. Cyl 1 looks to misfire the most after writing but then stops. Other seemingly random cylinders misfire too, but less so and then stop. Cyl 7 will sometimes miss post-write, other times it won't. After start and things settling, Cyl 7 might occasionally see a miss, other times nothing. We did do a pressure test a month or so ago and found nothing suggesting a leaking injector.Quote:
Misfires immediately after startup and writing are pretty common and nothing to worry much about, but the regular misfires on 7 jumped out as a possible injector leak given your starting issue.
This morning it seems that I was motivated enough to swap around some fuel injectors. 1 <---> 3, and 5 <---> 7.
I drove it around some with this tune: Attachment 133141
And the first log: Attachment 133139
The occasional misfires that were seen at Cyl 7 now appear to be at Cyl 5, and a single miss at Cyl 6. What is considered acceptable and what warrants replacing the injector? It has occurred to me that considering that there weren't misses at other cylinders, that that would be enough to warrant replacement, but I'm just speculating.
The vehicle sat for 90 minutes, and here's that log on the same tune: Attachment 133140
This one was still a really sooty start, but much smoother than in the past. I attribute this to no misses immediately after starting. There are again occasional misses at Cyl 5. Subsequent restarts on this tune were also quite sooty.
I changed this tune by bumping up the Startup Airflow ECT considerably: Attachment 133138
And the log: Attachment 133142
Here, as has been mentioned, there are post writing misses upon start. Then there are the now familiar spotty misses at Cyl 5. The restarts were much less sooty.
Then there's a log after just sitting for a few minutes, no tune changes: Attachment 133143
Note that there are misses at other cylinders, but none at Cyl 5. This observation is the basis for my "acceptable amount" question.
We do want to minimize fuel trims, but we don't want to achieve that by creating air or fuel models that aren't representative of the underlying, physical system. In this case, the airflow model isn't changed from baseline (TRD/Magnuson), but the fuel model is (due to injectors), so our global corrections should take place on the fuel side.Quote:
Originally Posted by Wynnded
The particular problem with simply chasing the lowest fuel trims possible on a Tundra is that we don't have the full transient models defined; the transient model has both airflow and fuel components. You can see this transient airflow model kicking in if you drop the polling interval low and log MAF against Absolute Load - on large transients you'll see logged Absolute Load deviate from Absolute Load as calculated via MAF and Engine RPM, which is due to the transient airflow model. The fuel model is the bigger issue, because different injectors have different transient characterization; any change in spray pattern/density affects wall wetting (fuel deposited onto intake surfaces), both impact factor (how much fuel hits intake surfaces) and tau (how long it takes that fuel to evaporate). Unless we are doing all of our tuning in steady state or filtering out all transients, we can wind up baking that fueling correction into our airflow model.
The PCM has a pretty wide range of corrections, but for our purposes, anything +/-5% or closer is generally acceptable, and +/-2-3% is about as good as it gets in a practical sense.
In this file, I've reset the MAF back to the TRD baseline, and carried your average correction (~+12.5%) into the injector constant. Keep in mind that equates to decreasing the injector constant, which tells the PCM that the injector is larger, reducing the injected fuel accordingly.
Attachment 133186
Per the following quote, I also threw in a healthy amount extra into the IAT airflow table - your hardest start in those was with an IAT of ~130F and ECT of ~150F, so some extra airflow at high IAT should help. You can experiment with pulling the ECT airflow back down based on the extra IAT airflow.
An occasional misfire, especially on different cylinders and particular conditions (startup, decel, etc.), aren't typically much cause for concern, there's no cylinder other jumps out as problematic in those logs, other than cylinder 5, as you're aware.Quote:
Originally Posted by Wynnded
Typically the concern comes in when we start to see regular, repeated misfires on a specific cylinder, particularly in conjunction with other drivability issues (significant Bank 1 vs Bank 2 fuel trim mismatch, noticeable impact to output, and so on).
Yes, this makes sense. Thank you for the clarification.Quote:
Originally Posted by SlowNStock
I'll experiment with this today. I had avoided bumping up the IAT table as initially I had though that it was getting enough airflow based on the high ECT airflow. Now I've realized that after the engine has been run up to full operating temp then shut off, with the engine compartment heat soaking and the IAT rising, the hotter air is less dense and the necessary flow needs to increase as well. Unless of course I'm thinking about that incorrectly.Quote:
Per the following quote, I also threw in a healthy amount extra into the IAT airflow table - your hardest start in those was with an IAT of ~130F and ECT of ~150F, so some extra airflow at high IAT should help. You can experiment with pulling the ECT airflow back down based on the extra IAT airflow.
I have noticed a mismatch between the fuel trims, I don't know what qualifies as significant though. I have ordered an injector to replace the one in cylinder 5.Quote:
An occasional misfire, especially on different cylinders and particular conditions (startup, decel, etc.), aren't typically much cause for concern, there's no cylinder other jumps out as problematic in those logs, other than cylinder 5, as you're aware.
Typically the concern comes in when we start to see regular, repeated misfires on a specific cylinder, particularly in conjunction with other drivability issues (significant Bank 1 vs Bank 2 fuel trim mismatch, noticeable impact to output, and so on).
Thanks again for the lucid explanations, taking the time to look at my tunes and all the logs, as well as answering all my questions and for coaching me through my tuning dilemma!
With the IC that low and the TRD MAF reset, the ECU can't compensate with fuel trims to reach stoichiometric. If memory serves, I've toyed with this a little and found that when gradually increasing the IC from about the same starting point, it needed to be very close to the injector suppliers recommended value to attain ~14.7AFR. This is where us uncouth tuners would then wreak havoc on the transfer table. The lowered IC also appeared to exacerbate misfires at Cyl 5.Quote:
In this file, I've reset the MAF back to the TRD baseline, and carried your average correction (~+12.5%) into the injector constant. Keep in mind that equates to decreasing the injector constant, which tells the PCM that the injector is larger, reducing the injected fuel accordingly.
Log:Attachment 133214
It's probably prudent to pause here until I can replace that injector. If it's leaking at all, even if it wasn't detected when I had the system pressure tested, it's just to paramount to ignore.
I'm still very intrigued as to how to correctly lower fuel trims without making the transfer table graph look like a scribble. When I've looked at my LTFTs using an untouched transfer table, they've invariably been particularly lean on the low end, and just about equally rich in the upper end.
If you're interested, here's a log of a warm start using the original scaled IC, my original crude transfer table edits, and your Startup Airflow ECT/IAT edits. It might be irrelevant with that suspect Inj 5.
I had the modified and baseline files flipped on my end when I was comparing, so the injector constant should have increased by 12.5% (to 0.078947) since I was carrying a -12.5% correction over, not vice versa - mea culpa for not taking a second look before posting.Quote:
Originally Posted by Wynnded
Depending on the actual trims you're seeing low vs high, they may be fine as-is.
Ahh, I think we've all done that. I know I surely have. No worries! See, I neglected to include the warm start log that I mentioned:Quote:
Originally Posted by SlowNStock
Attachment 133242
I received the replacement injector this morning and changed it out. That has eliminated the misfires at Cyl 5, outside of the few that also occur at other cylinders at startup but do not reoccur afterward. I've adjusted the IC a little bit to try to balance the lowRPM leaner with the higherRPM richer LTFTs maintaining the TRD transfer table. The adding fuel to subtracting fuel transition happens at about 2k RPMs which is the engine speed at 75mph, perfect for long Interstate drives.
I have another obligation, but when that's complete I'm going to check the fuel pressure again as the start issue still happens after the engine has been warmed up and then sits for ~15+ minutes. I might be able to fiddle around a little tomorrow, but that would be it for about 10 days.
I don't know if this tells us anything useful, but here we go.
Beginning from an overnight sit and cooldown, the truck will always start eagerly on the first turn of the key.
Today I started it and let it warm up until the ECT read 86F. Then I shut it off, waited for less than 30 seconds and restarted it. Fine.
Attachment 133406
I shut if off again then let it sit for 15 minutes. The restart hesitated slightly but was passable. Then I drove it a short distance until the ECT read 158F. I shut it off, then restarted it. Fine.
Attachment 133407
Next I let it sit for 15 minutes and restarted it. This required two attempts before it started. Then I drove it to bring it up to full operating temperature.
Attachment 133408
I shut it off and waited for about one minute and restarted it. Fine. Drove back home.
Attachment 133409
Upon arriving I shut it off and let it sit for 15 minutes. It just started, but just barely before the Auto Cranking timed out (I think I read that it cranks for 10 seconds).
Attachment 133410
If nothing else, this just seems to indicate that the issue isn't simply a general starting issue, but a starting issue more specific to a warmed engine restarting after sitting for 15 minutes or more. How long it needs to sit until a normal restart occurs will likely take much longer to try to determine.
This may sound outlandish, but it's a question that's evolved in my head. What if there are one or more injectors that slowly leak for an undetermined amount of time after having been active, but not so much as to create an immediate restarting issue? Could they slowly leak enough that after 15 minutes there's enough fuel to cause a starting problem? After another undetermined amount of time could they stop leaking allowing the fuel in the cylinders to evaporate enough returning to a more ideal starting mixture "the next day"? This would suggest that the injectors are more likely the issue than the tune, but then I remember that there are others who are experiencing this and they're using injectors from a different manufacturer and of a different flow rating.
Update:
Five hours later it took three (3) tries before the truck started.
Attachment 133425
I finally got fed up and changed back to the TRD injectors. Starting is perfect for all starting conditions now. With the TRD injectors, I experimented with some of the tables that I thought might affect starting. For example, for the Startup Airflow ECT table, I filled it with a value of 12g/s and it still started fine. I changed the Offset table from stock values to the ones suggested for the 750cc injectors. Staring was unaffected. I'm going to contact the seller and see what might be done.
I called the place that I bought the injectors from. Their take on it being an injector issue was that it would be unlikely on a grand scale but they'd be willing to take my money if I insisted on sending them in for testing.
Soooo....
I reinstalled the 750s again this morning to have another go at things. I used the same tune as with the TRD injectors changing only the IC. Then I went back to what @SlowNStock said about increasing Startup Airflow values in increments. As I went up, I got less and less sooty emissions from the tailpipe on immediate hot starts all the way up to the limits of the table, 20L/s. However, with each progressive change, starting remained problematic the longer it sat, starting after about 15 minutes.
I made logs of both iterations of the tune in an effort to try to spy any differences in fuel and airflow during cranking, but nothing that seemed exceptional. A couple milliseconds difference either way with the IPW, and similar variations of mass airflow. As always, I'm open to suggestions. :)
Up till now, the first start of the day has been in the morning when the ambient temperature was in the 50s and the truck started fine. Today I waited until midafternoon and the temp was in the low 80s and the truck started as though it had been run earlier in the day and cranked through the first attempt and started on the second. Further starts seconds later were successful. One hour later the truck cranked through the first attempt and started on the second, further starts were successful. An additional hour later yielded the same results. Here are the logs for each hour. In the tune the Airflow ECT values appear extraordinarily high, but I can literally use any value within the permitted table range and get the same starting behavior. Next I will see what happens at 60 or 70F after sitting overnight.
Attachment 134360
Attachment 134361
Attachment 134362
Attachment 134363
*In the logs there is an anomaly between some restarts where the MAF rises, the ECT, and/or IAT drop. I suspect that this is the SAIS bypass module and will remove it again. It was reinstalled while running the TRD injectors to see if it had any influence but it didn't.
I?ve just purchased a tundra! Yesterday! I?ll be making some adjustments very soon. Tuned 3 NA 5.7?s pretty well and also have an Avalon? which I?m reading and playing with through ktag. I?ll be wanting to learn, just as you on how these two can be read and compared, HPtuners and .bin 😉 then possibly learn Avalon 2GR-FE things from there. Is there anything I can send you to help you on this? My plan was to makrr we a change through HP, then read in .bin to see the changes.
@SlowNStock
So, with all the back and forth and your very generous explanations and patience, it appears that there is something faulty with my injectors. @Snivilous was kind enough to loan me a new set of 720cc injectors and all starts since then have been flawless, even using the stock Startup Airflow table. Tomorrow I will be reaching out to the company that I purchased the 750cc injectors from to see what they can do for me.
Still experiencing perfect starts. I finally got the problematic injectors in the mail to be tested. Now we wait to hear back.
In the interim, I noticed a different anomaly and am curious to see if anyone else has encountered the same. When decelerating where the gear is high and the RPMs are low, the ECU oscillates between OL/CL and RPMs hunt. This happens at the bottom of an exit ramp, or when decelerating off throttle approaching a traffic light. I read somewhere that someone else was experiencing something similar and they though that maybe the ECU was anticipating a downshift, but I'm unable to locate their posts on the matter. Here is a log (start at the 2 minute mark) and my current tune.
Glad to hear you were able to get startup fixed via injectors!Quote:
Originally Posted by Wynnded
What you're seeing is the PCM entering flex lockup to go into DFCO - as it locks up, it slows the truck just enough to drop out of flex lockup, then the truck gains enough speed with it unlocked to enter flex lockup again, and the cycle repeats.
Takes a specific set of conditions where the truck can gain enough speed with the converter unlocked but lose enough speed to keep the converter from staying locked, while in a gear with flex lockup enabled (3-5). 5th is generally the most problematic, simply because of how it falls with regard to engine braking and vehicle speed.
There are a couple options to remedy:
1) Force a downshift sooner (5-4 in this case).
2) Increase flex lockup hysteresis (the difference in speeds and/or TPS between flex lock and unlock).
3) Disable flex lockup, either for the gear or that RPM range.
I'm glad as well, many thanks for your patience.Quote:
Originally Posted by SlowNStock
I never would've even guessed that flex apply/release would've been where this is happening, having never really read anything about it. I will get into this on the weekend!
This hunting appears to happening in 6th gear as well, where Flex-Lock is not implemented. Unless of course I'm not understanding. I'm intrigued that this hunting has started when I've not made changes to any transmission tables in a very long time.
Attachment 136532
Well, I'm pretty confident that I don't know what it is that I'm doing. But I'm trying. :D
In an effort to try to force an earlier 5-4 downshift, I went to Transmission > Shift Scheduling > On-Power > Normal/Normal Fault/Cold/Cold Fault/Tow-Haul/Tow-Haul Fault and changed the cells in the 0% and 13% columns to the same values that are in the 25% column just to see if that made a difference. This would be changing the 875 rpm Output Shaft speed to 1600 rpm in all of those tables.
To increase hysteresis, I went to Transmission > Torque Converter > Flex Apply/Release > Output Speed vs. Throttle > D/S6 and to the 5th App and 5th Rel tables. In the Apply 5th Gear table, I tested increasing the 0% column value by 5, 10 and 15%. Not decerning an improvement, I reset the table back to stock. In the Release 5th Gear table I tested lowering the same column the same percentages, but was not able to notice an improvement. I was not able to be sure in what way to change TPS hysteresis, so I didn't try anything.
Trying to disable Flex-Lock for that gear, in Transmission > Torque Converter > Flex Apply/Release > Output Speed vs. Throttle > D/S6 I changed all the values in the Apply and Release 5th Gear tables to the same values that are in the Apply/Release 6th Gear tables as that gear is not suppose to utilize Flex-Lock. Unfortunately there was no change in behavior.
Interestingly, the oscillation appears in 3rd through 6th gears. I'm rather mystified.
@SlowNStock
Curious to know if it appears that I tried to implement your suggestions at least somewhat correctly.
Thanks!Quote:
Originally Posted by Wynnded
I tested briefly yesterday, this is happening with my reference "stock TRD tune" as downloaded from HPT. I took the intake apart and it's spotless, as is the throttle body. I thought that maybe something may have snuck in. Checked all the vacuum hoses too. Nutty stuff...:p
Throw up a copy of this tune, and I'll try to take a look later this week.Quote:
Originally Posted by Wynnded