Transient fueling issues

What are the effects of transient fueling when doing steady state MAF and SD tuning?
What I have come across is that my steady state tunes once put into my regular tune become rich and am wondering if this transient fuel section should also be disabled or is skewing my SD and MAF tunes?
Is there some transient fueling courses or information that can be found on tuning transient section of my tune? Also since I have become a paid member of HP tuners forums shouldn't I be able to have access to all videos on training available?

did you zero out injector tip temperature for while tuning?

Yep yep.

Do not know who thought this was a good idea but it is not. Do not believe what you read. Make sure it is backed up with logic. You will need to do some reading on ECM 12303, injector tip temp and the rich after flash issue. I spent about 7 months finding that in the ECM. It was implemented by HPT in early 2016 and in production by mid 2016.

https://forum.hptuners.com/showthread.php?66837-Rich-After-Flash-Injector-Tip-Temperature&p=497882&viewfull=1#post497882

https://forum.hptuners.com/showthrea...ch-after-Flash

Now that's just awesome. Research, research and dang.. so after reading all that it seems I should go back to MAF tune and get it within 1% then do the Injector temp offset calibration process right?
Also they seemed to have mentioned dialing in the O2 sensors. Does this mean I change the default values of MIN and MAX lean/rich settings from 300 and 650 to their true readouts as shown on the O2 tables? Like 200 and 900 for min/max.
I noticed that they go much further than both of those stock values and thinking that too can also scew the fuel trims correct?

Not hijacking this thread, but was just reading up on transients which led me to the comments on injector tip temp. Found my stock file to be zero'd out! ECM 12303, Injector offset vs Injector tip temp. 2014 Yukon (gen4) with OS 12656198. File is in the repository if anyone wants to see it. Not sure what to think of this.

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Originally Posted by [email protected]

Now that's just awesome. Research, research and dang.. so after reading all that it seems I should go back to MAF tune and get it within 1% then do the Injector temp offset calibration process right?
Also they seemed to have mentioned dialing in the O2 sensors. Does this mean I change the default values of MIN and MAX lean/rich settings from 300 and 650 to their true readouts as shown on the O2 tables? Like 200 and 900 for min/max.
I noticed that they go much further than both of those stock values and thinking that too can also scew the fuel trims correct?

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So every motor has the spot where it wants to run. For my ZL1 it is the 122 or 131 (injector tip temp) cells. I chose 122 and set it to zero. I tuned the MAF filtering all but that. Once done any variation in fueling I used to adjust injector tip temp. Some you have to add some remove. You NEVER get it perfect. I have 113,122,131 all dialed. Anything in those cells makes zero difference in fueling. All the others I get close but always make sure it errors rich.

I have vets that run 140, 149 so that was their starting point. Every one is different. Why it is called tuning not boilerplating.

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Originally Posted by NotSure

Not hijacking this thread, but was just reading up on transients which led me to the comments on injector tip temp. Found my stock file to be zero'd out! ECM 12303, Injector offset vs Injector tip temp. 2014 Yukon (gen4) with OS 12656198. File is in the repository if anyone wants to see it. Not sure what to think of this.

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This is done a lot from the factory. As no one knows the code in the ECM it could be that OS does not use this. If you have not changed injectors it should not cause too many issues.

However, just zeroing an adder that has values for the sake of tuning is a bad idea.

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Originally Posted by jsllc

This is done a lot from the factory. As no one knows the code in the ECM it could be that OS does not use this. If you have not changed injectors it should not cause too many issues.

However, just zeroing an adder that has values for the sake of tuning is a bad idea.

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I have changed injectors, they are now Deatschwerks 72lb. I'm guessing that as long as I pay attention to IVT, any fueling changes I make should be in a similar injector tip temp range, IF there are any hidden adjustments going on in the OS for tip temp. So what do you do if you have tip temp modifiers in your cal and you change injectors? Leave them as-is and tune with them? They are just calculations/estimates of what is going on at the injector after all, and would have a similar affect on any injector?

Funny stuff these OE cals/OS's, proliferation abounds (HP engineers say "YEP!!").

Your assumptions are wrong. IVT has nothing to do with this pulse width adder.

I make sure my injector data is 100% correct. Then tune MAF at my home cell (which I set to zero) for injector tip. Once MAF is correct for home cell any fueling error at different injector tip temps I add or delete to make the MAF error free in adjacent cells and not lean in all others.

This is a calculated pulse width adder.

So then the question remains as to what zeroing the home cell means? At idle with normal to just higher and lower cells above and below get zeros and the rest get tuned right? So what's the logging you use for information on those changes and it seems to me there are other fields to adjust like the transient fuel mass evaporation and impact factors which I'd think are directly related correct?

Zeroing the home cell means to chose an ITT cell that is "normal" where your car typically runs. For example, the 122 deg.F cell in the ITT table.

Do your MAF tuning while the car is running at close to 122deg.F ITT. Once you have that squared away, and your MAF is looking good at 122 (or wherever yours is), then you leave the MAF curve alone and adjust for fueling error in the other ITT temperature cells by adding or removing a small amount in the relevant cells in the ITT table.

Otherwise, you'll chase your tail forever trying to get MAF perfect when the ITT changes. It makes a pretty significant difference to fuel trims when your ITT changes. A small offset can be a significant adder percentage-wise, especially at low pulsewidths with larger injectors.

So then this is where after tuning MAF on the road I then do the heavy idling, shutting car off and then logging the AFR changes and making small incremental changes to the surrounding ITT cells accounting for the temp changes in fueling AFR at idle speed correct?

I do it by flashing while hot, then driving and logging while the ITT falls. But yes, you can do it at 1100 or 1200 rpm in a driveway if you want.

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Originally Posted by [email protected]

So then the question remains as to what zeroing the home cell means? At idle with normal to just higher and lower cells above and below get zeros and the rest get tuned right? So what's the logging you use for information on those changes and it seems to me there are other fields to adjust like the transient fuel mass evaporation and impact factors which I'd think are directly related correct?

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You are making this too hard. Zero means set to zero. This is the table for my car with my mods. It will NOT work for any other car. As for this adjustment a little goes a long way. I do it all at idle so I have zero transients
Attachment 99676

My cars tables are zeros in the normal operating range so that's one less thing that needs adjustment.
Now these values I see that represent fuel evaporation from the heads and that boundary injection timing seem like places to dial in when your stomping the pedal and getting rich or lean spikes right?

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Originally Posted by RobZL1

Zeroing the home cell means to chose an ITT cell that is "normal" where your car typically runs. For example, the 122 deg.F cell in the ITT table.

Do your MAF tuning while the car is running at close to 122deg.F ITT. Once you have that squared away, and your MAF is looking good at 122 (or wherever yours is), then you leave the MAF curve alone and adjust for fueling error in the other ITT temperature cells by adding or removing a small amount in the relevant cells in the ITT table.

Otherwise, you'll chase your tail forever trying to get MAF perfect when the ITT changes. It makes a pretty significant difference to fuel trims when your ITT changes. A small offset can be a significant adder percentage-wise, especially at low pulsewidths with larger injectors.

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Thank you Rob and Scott, This thread has helped me out! Only took a dozen times reading and logging to understand.
Question: When logging ITT error, do you log it as percent AVERAGE? If so, can I just copy past multiply percent half into the ITT table to fix?

thanks

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Originally Posted by marksrig

Thank you Rob and Scott, This thread has helped me out! Only took a dozen times reading and logging to understand.
Question: When logging ITT error, do you log it as percent AVERAGE? If so, can I just copy past multiply percent half into the ITT table to fix?

thanks

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Percent does not work because it is a pulse width adder. There are certain numbers and only multiples of those numbers can be used.

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Originally Posted by jsllc

Percent does not work because it is a pulse width adder. There are certain numbers and only multiples of those numbers can be used.

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I just spent the good part of the day and a half tank of gas tuning the MAF based at 120* ITT to find out I cant log this error? Didn't seem to matter what I did I couldn't get it to cooperate after the flash.
Can you elaborate on how to properly log this error for the offset table?

So after taking a closer look at the ITT table, I realize the values in the table are all divisable by .007813 so this is the "certain numbers" you were talking about.
The scanner is definately setup wrong, tomorrow is a new day and I still have a half a tank.

So far all I can see is to turn off transient all together and dian in MAF best you can then turn transient fueling back on and adjust for the EQ changes found between having transient off and then back on.
I thought I'd set MAF and SD tables and be good but the stock tune is hosed up 8 ways to Sunday between tables unpopulated or just filled with single values. What a nightmare to un-smurf stock...

So would the other transient values have to be done in a new thread or can we continue working on transient values here?
Minimum pulse width adders, accel/deceleration ratios, wall setting, etc?