Crank Fueling - Question on "Right" Timer

[1bad68ls]

I am working on my crank times for cold starts at higher temps. My cold start crank times are < 0.7seconds at ambient temp of 70F and lower, however they are long when the ambient temps are >80F outside and the car has been soaking in the garage for 12+ hours.

I am tuning the [Cranking FA Mult Stage 1 vs. Cranking Time] table, but I am unclear how the timer works. The HPT table description is:

[ECM] 12320 - Cranking FA Mult Stage 1 vs. Cranking Time: These tables are FA multipliers that determine fuel delivery in relation to time. As cranking continues the AFR is selected from lower rows of the table until it finally stays at the last row in the Stage 2 table. Usually you will see a pulsing fuel pattern in these tables.

It seems the HPT description of "Cranking Time" is wrong, because the table goes out 43,200 seconds (12 hours). I am guessing the table is based on ENGINE OFF TIME and I now data log the [Engine Off Time].

QUESTIONS:
Looking for feedback on a few questions:
1) Is the 12320 table based on Engine Off Time?
2) If the Engine Off Time is maxed out (65,536 seconds/18 hours), will the ECM use the data for the next cold start from the last column (43,200 seconds), or the first column (0 seconds)?
3) How do find/get access/see the Stage 2 fueling tables to tune it?

Thanks,
Jeff

[Cringer]

I am working on my crank times for cold starts at higher temps. My cold start crank times are < 0.7seconds at ambient temp of 70F and lower, however they are long when the ambient temps are >80F outside and the car has been soaking in the garage for 12+ hours.

I am tuning the [Cranking FA Mult Stage 1 vs. Cranking Time] table, but I am unclear how the timer works. The HPT table description is:

[ECM] 12320 - Cranking FA Mult Stage 1 vs. Cranking Time: These tables are FA multipliers that determine fuel delivery in relation to time. As cranking continues the AFR is selected from lower rows of the table until it finally stays at the last row in the Stage 2 table. Usually you will see a pulsing fuel pattern in these tables.

It seems the HPT description of "Cranking Time" is wrong, because the table goes out 43,200 seconds (12 hours). I am guessing the table is based on ENGINE OFF TIME and I now data log the [Engine Off Time].

QUESTIONS:
Looking for feedback on a few questions:
1) Is the 12320 table based on Engine Off Time?
2) If the Engine Off Time is maxed out (65,536 seconds/18 hours), will the ECM use the data for the next cold start from the last column (43,200 seconds), or the first column (0 seconds)?
3) How do find/get access/see the Stage 2 fueling tables to tune it?

Thanks,
Jeff

1) Yes it is mislabeled. It is engine offtime.
2) Yes, the last column is used.
3) I think this is also mislabeled/hold over from the Gen3 ECM's...I don't think there is a Stage 2 table in Gen4. If there is, HPT didn't map it for any Gen4 that I have ever seen.

[1bad68ls]

Thanks Cringer,
I have this long crank issue when my car sits overnight in the garage at 80+ temps. I have modified this table several times in different ways, but the changes seem to make little/no impact to my fueling.

Before I crank the car, I data log the parameters (KOEO - key on engine off) to make sure the Engine Off Timer is 65,535 (maxed out) and all temps are in the 80s.

I was also expecting the calculated [Injector Flow Rate] to update using the latest data I put in the cell 86F/43,200s of the 12320 table. But this does not update (even if I put all zeros in the 12320 table).

The injector PW is always zero at KOEO, so I cannot use that....
Is there an available calculated fuel parameter that I can look at (at KOEO before the start) to see what the ECM would deliver at crank?

[Cringer]

There are a lot of tables involved here. It will be hard to solve this without a tune, log, and a stock file to compare to as well as a list of mods (as well as what fuel you are using). I would suggest returning all this stuff back to stock (except for the start up airflow, which you would need more).

Cranking Issues
Fuel > General > FA Stage 1 table
Fuel > General > IVT Terms (will impact Transient Fueling, may be a problem if you have scaled injectors)
Fuel > Open Loop / Base > Multiple tables
Idle > Airflow > Startup Airflow
Airflow > General > Cranking VE
Fuel > General > Injection Timing (mainly applicable to your cam and fuel injector size and spray pattern)
Fuel > Transient (definitely used for cranking and bad changes here have potential to mess things up)
There are also other multipliers in the airflow and throttle body that I won't mention

IPW won't be calc'd unless the engine is running or cranking.

This video may help, it is dealing with hot starts, but it explains the relationships here.
https://youtu.be/Sz878VXfYD8?si=kmSg3MsTtuBYmP7a

[1bad68ls]

Thanks Cringer,
I appreciate your help and agree many other factors impact crank starts, which is why I want to see the calculated fuel to be delivered before I hit the key (and impact my cold start).
The ECM calculates final crank fueling before delivery but HPTuners does not provide access to that acquisition parameter.

The OEM calibration tools (such as ETAS/ATI...) read a file in that has a list of all available acquisition and calibration parameters, with their ECM addresses, scaling and other properties.

Does HPTuners have a method to read other ECM parameters (which are not shown in the standard HPT)?

[Cringer]

Thanks Cringer,
I appreciate your help and agree many other factors impact crank starts, which is why I want to see the calculated fuel to be delivered before I hit the key (and impact my cold start).
The ECM calculates final crank fueling before delivery but HPTuners does not provide access to that acquisition parameter.

The OEM calibration tools (such as ETAS/ATI...) read a file in that has a list of all available acquisition and calibration parameters, with their ECM addresses, scaling and other properties.

Does HPTuners have a method to read other ECM parameters (which are not shown in the standard HPT)?

If you are savvy enough to get the .BIN file for your tune, use 3rd party tools to reverse engineer the hexadecimal code to create an .XDF file...then yes, HPT does allow for this. You have to buy the User Defined Parameter license first and then it will read the .XDF file and allow you to tune any table, scalar, or switch in the tune. There are no safety nets here, so you can really break things. This is generally well beyond the technical reach of 99% of tuners since this is really the edge of software and hardware engineering.

However, IMHO since the Dynamic Airflow calculation is 0 g/s with KOEO, then the calculated IPW would also be zero. And even if you could get this number, I am not sure how this would help solve your issue.

[DanN]

1) Yes it is mislabeled. It is engine offtime.

Hi Cringer - How did you come to determine this was engine off time? I don't understand how that would be a useful metric for tuning, given so many other aspects would have a larger effect over the course of half a day (43,500 seconds).

Doesn't it seem more likely the time scale is mislabeled, and it's more like the Gen3 where it's 0 to 16 seconds for the same table?

[Cringer]

Hi Cringer - How did you come to determine this was engine off time? I don't understand how that would be a useful metric for tuning, given so many other aspects would have a larger effect over the course of half a day (43,500 seconds).

Doesn't it seem more likely the time scale is mislabeled, and it's more like the Gen3 where it's 0 to 16 seconds for the same table?

Heat soak, changing fuel rail pressure, amount of fuel in the port that is liquid vs vaporized. It is a useful metric.
Yes stuff is mislabeled and improperly scaled in HPT. Log a support ticket, they will tell you that Gen4 is out of support.

[07GTS]

u can change the values from sec to min to hours

[DanN]

u can change the values from sec to min to hours

Well sure - but that doesn't make sense for cranking time; no one is cranking for 12 hours.

It could be for heat soak; the Gen5s have that ([ECM]33554 - "Soak Time Multiplier") - but it is a completely different table, and had no actual effect in the tune I looked at, with a steady rate of 1 across all time columns and only 1 row - a total of only 9 cells.

The Gen4 table appears to more closely match the Gen3 table; they are both [ECM]12320, and have the same number of cells (17x17 - though the axis are swapped).

I'm nervous about changing the column axis from 0 - 43,200 to 0 - 16 seconds; that's above my noob status and skillset. I mean, I can make the change, but I don't know what the risks are.

If the table is just named incorrectly and it really is heat soak, how could we graph it and/or modify the table to prove that? If I zero all the cells from 60 seconds up, and I can't get it to start any more after resting for > 1 minute I suppose that would do it?

[Cringer]

Well sure - but that doesn't make sense for cranking time; no one is cranking for 12 hours.

It could be for heat soak; the Gen5s have that ([ECM]33554 - "Soak Time Multiplier") - but it is a completely different table, and had no actual effect in the tune I looked at, with a steady rate of 1 across all time columns and only 1 row - a total of only 9 cells.

The Gen4 table appears to more closely match the Gen3 table; they are both [ECM]12320, and have the same number of cells (17x17 - though the axis are swapped).

I'm nervous about changing the column axis from 0 - 43,200 to 0 - 16 seconds; that's above my noob status and skillset. I mean, I can make the change, but I don't know what the risks are.

If the table is just named incorrectly and it really is heat soak, how could we graph it and/or modify the table to prove that? If I zero all the cells from 60 seconds up, and I can't get it to start any more after resting for > 1 minute I suppose that would do it?

Change all cells to 1.00 and crank the engine. Log the commanded EQ ratio.
Change all cells to 2.00 and crank the engine. Log the commanded EQ ratio.
You can log engine off time to you know what time column it is hitting.
Return the table to stock and allow happiness to enter your life. You shouldn't really have to mess with this table.
I would avoid changing the units to fortnight, but then again, I am an American.

[DanN]

Change all cells to 1.00 and crank the engine. Log the commanded EQ ratio.
Change all cells to 2.00 and crank the engine. Log the commanded EQ ratio.
You can log engine off time to you know what time column it is hitting.
Return the table to stock and allow happiness to enter your life. You shouldn't really have to mess with this table.
I would avoid changing the units to fortnight, but then again, I am an American.

Given the table is on a 12 hour time scale, I'd imagine a 2 week scale would be even less useful.

I'll try both of our theories over the next few days.

What I can say is that table improved my hot starts, and I 'pretended' it was on a 0 - 16 second time scale.

I have tried to log the time off PID, but it seemed like as soon as I turned the ign on, it reset. I'll give it another go.

PS:

It just so happens that I've been logging off time for a while, so I did up a quick chart from a datalog I took last night. Of course it just ends up being pinned to 2 cells, because my off-time was ~2700 seconds. Included below for reference.

[DanN]

Related Tune and Log:

Apparently my datalog is too large to upload. I'll get another one after work.